Topic Highlight Open Access
Copyright ©2014 Baishideng Publishing Group Co., Limited. All rights reserved.
World J Gastroenterol. Apr 21, 2014; 20(15): 4256-4262
Published online Apr 21, 2014. doi: 10.3748/wjg.v20.i15.4256
Interval to surgery after neoadjuvant treatment for colorectal cancer
Nir Wasserberg, Department of Surgery B, Rabin Medical Center, Beilinson Campus, Petach Tikva and Sackler School of Medicine, Tel Aviv University, 69978 Tel Aviv, Israel
Author contributions: Wasserberg N solely contributed to this paper.
Correspondence to: Nir Wasserberg, MD, Department of Surgery B, Rabin Medical Center, Beilinson Campus, Petach Tikva and Sackler School of Medicine, Tel Aviv University, Haim Levanon 55, 69978 Tel Aviv, Israel. nirw@clalit.org.il
Telephone: +972-3-9376202 Fax: +972-3-9376202
Received: September 28, 2013
Revised: November 11, 2013
Accepted: January 14, 2014
Published online: April 21, 2014

Abstract

The current standard treatment of low-lying locally advanced rectal cancer consists of chemoradiation followed by radical surgery. The interval between chemoradiation and surgery varied for many years until the 1999 Lyon R90-01 trial which compared the effects of a short (2-wk) and long (6-wk) interval. Results showed a better clinical tumor response (71.7% vs 53.1%) and higher rate of positive and pathologic tumor regression (26% vs 10.3%) after the longer interval. Accordingly, a 6-wk interval between chemoradiation and surgery was set to balance the oncological results with the surgical complexity. However, several recent retrospective studies reported that prolonging the interval beyond 8 or even 12 wk may lead to significantly higher rates of tumor downstaging and pathologic complete response. This in turn, according to some reports, may improve overall and disease-free survival, without increasing the surgical difficulty or complications. This work reviews the data on the effect of different intervals, derived mostly from retrospective analyses using a wide variation of treatment protocols. Prospective randomized trials are currently ongoing.

Key Words: Rectal cancer, Chemoradiation therapy, Neoadjuvant, Surgery, Interval to surgery, Colorectal cancer

Core tip: The traditional 6-wk interval between chemoradiation and surgery in the treatment of rectal cancer was based primarily on a single publication. There has been a trend in recent years to prolong this interval based on studies showing that it may be advantageous in terms of tumor downstaging and pathologic complete response, without increasing surgical difficulty or complications. The data so far are derived largely from retrospective studies using a wide variation of treatments. Further investigations with a higher level of evidence are required to definitively resolve this issue.



INTRODUCTION

Colorectal cancer is the fourth most common malignancy in the United States and the second most frequent cause of cancer-related death[1]. Approximately 50% of rectal cancers are diagnosed at the locally advanced stage, with metastatic spread to the lymph nodes in two-thirds of these cases[2]. The standard treatment of rectal cancer is curative surgical resection, combined with preoperative chemoradiation therapy (CRT) for T3 and/or node-positive tumors of the mid/low rectum (located 12 cm from the anal verge), and additional adjuvant therapy if indicated[3-7]. Local recurrence rates following CRT and surgery are less than 10%, especially when modern surgical techniques such as total mesorectal excision are used[8]. Studies have shown that the addition of CRT has a beneficial effect on tumor downstaging and pathologic complete response (pCR)[9,10], with improved tumor resectability, possibly increased sphincter preservation rates[11,12], and maybe even increased overall survival rates[13]. Recent evidence suggests that CRT-induced tumor regression may allow for a “watch and wait” approach that avoids surgery altogether in selected patients[14].

Several strategies have been suggested to improve the response to CRT, including better patient selection[15], case-personalized approach with specific genetic fingerprinting[16,17], variations in the radiation and chemotherapy regimens[18-20], and additional chemotherapy during a “rest interval” after CRT[21]. In recent years, researchers have directed attention to optimizing the CRT-surgery interval[22], which remains controversial[22]. Ideally, the most favorable interval should facilitate maximal tumor regression, defined by maximal tumor downstaging and downsizing, with minimal risk of deterioration in the surgical results, defined by low short- term morbidity in mainly relation to perineal and anastomotic complications and better long-term oncological and functional outcomes.

Early trials conducted from the 1970s to the late 1990s used a broad range of CRT-surgery intervals with widely varying results[23-27]. The 1999 Lyon R90-91 trial[28] was the first to specifically address this issue. A cohort of 201 patients with rectal cancer were prospectively randomized to undergo surgery at 2 or 6 wk after completion of radiotherapy. The longer-interval group was found to have a better tumor response and improved pathological downstaging, with similar rates of complications and survival to the shorter-interval group. The authors concluded that 2 wk may be too short a time to achieve maximum benefits of radiation-induced tumor regression. As a consequence of this study, surgery at 6 wk after completion of radiotherapy became the standard of care. However, later data suggested that the response to CRT in patients with rectal cancer is time-dependent, and complete tumor regression may take months[29]. Thus, the interval between CRT and surgery should be sufficient to attain greater tumor regression and to permit the acute radiation effects of tissue swelling and local inflammation to dissipate before surgery. At the same time, a too-long interval poses a risk of tumor progression during the wait for surgery, with a higher rate of distant metastasis. Furthermore, the accelerated repopulation of tumor cells that are not completely eradicated could lead to multidrug resistance. These drawbacks may explain the reported lack of change in survival in patients with rectal cancer despite the improvements in local control[30]. Others have raised concerns that delaying surgery beyond 6 to 8 wk from CRT could also increase the technical operative risk due to radiation-induced pelvic fibrosis, thereby increasing the rate of surgical complications[31] and loco-regional recurrence[32,33].

The purpose of the present review was to summarize the current data on the optimal timing of surgical resection after CRT for rectal cancer.

EFFECT OF PROLONGED CRT-SURGERY INTERVAL ON ONCOLOGICAL OUTCOME
Tumor regression and rate of pCR

The time elapsed from after preoperative CRT is one of the factors affecting the process of T or N stage reduction. Foster et al[22] systematically reviewed 15 studies, each based on different neoadjuvant treatment indications and regimens and different CRT-surgery intervals. Four of the 9 studies that evaluated the effect of a prolonged interval on tumor regression reported a significant improvement. Most of the studies did not apply a histologically based tumor regression grade to estimate the degree of postoperative tumor regression and fibrosis[34], although proven to be of prognostic significance[35]. The only randomized study among these publications was the Lyon R90-01 trial[28] in which the longer-interval group had significantly higher rates of a positive clinical tumor response (71.7% vs 53.1%) and pathologic tumor regression (26% vs 10.3%) than the shorter-interval group (P < 0.05 for both factors). They also had a nonsignificantly higher rate of pCR (13.8% vs 7.1%).

The Dutch surgical colorectal audit is the most recent published study to address the CRT-surgery interval in terms of tumor regression[36]. A total of 1593 patients with rectal cancer were evaluated. The results showed that delaying surgery by 10-11 wk from the end of CRT was associated with the highest chance of a pCR. Accordingly, in a study of predictive factors of pCR, Kalady et al[37] concluded that an extended interval between completion of neoadjuvant therapy and surgery was the single most important determinant. This finding was in line with the study of Garcia-Aguilar et al[38] which analyzed the impact of both prolonging the CRT-surgery interval and adding resting-period chemotherapy. Rates of tumor downstaging and pCR significantly increased after longer intervals to surgery (18% vs 25%).

Using another approach, Perez and co-workers[39] investigated changes in labeled fluoro-2-deoxy-d-glucose uptake on positron emission tomography/computed tomography (PET/CT) imaging, at baseline and 6 and 12 wk after CRT. The maximal standard uptake value (SUVmax) was measured at 1 and 3 h at each time point. The authors found that patients with an increase in early SUVmax were less likely to have significant tumor downstaging, suggesting that the variation in PET/CT SUVmax at 6 wk might serve as a criterion for selecting patients who may be expected to benefit from a longer CRT-surgery interval.

A few studies of the impact of the CRT-surgery interval included an analysis of nodal regression[40-44]. No significant impact of a longer interval was found. The Lyon R90-01 trial, however, yielded a significant effect of a longer interval on nodal regression in patients with N2 disease[28]. Similar results were noted in the Dutch colorectal surgery[36] audit in which surgery was performed 15-16 wk from the start of CRT. Others found that nodal retrieval is time-dependent, with a negative correlation after longer post-CRT time[45]. Thus, it is possible that lymph nodes have a more rapid response to CRT which may override the effect of prolonging the CRT-surgery interval[46].

Surgical margins

The status of the resection margins, including the distal mucosal and mesorectal margins, and specifically, the circumferential margins, is one of the most important factors determining disease recurrence after surgery[47,48]. Neoadjuvant CRT has been associated with reduced rates of local recurrence and tapering of the recommended margins[49]. Among the studies that examined the effect of a prolonged CRT-surgery interval on resection margin clearance[41,44], one found microscopically involved margins (R1) in 2% of patients who underwent surgery before 44 d from CRT and in 1% of patients who underwent surgery later[44]. Another reported a similar rate of positive circumferential resection margins (2.8%) with short (< 41 d) or longer intervals[41]. In neither was the effect of a prolonged interval on resection margins significant. This was true of other studies as well[22].

Prognosis

Both tumor downstaging and pCR are correlated with a better oncological outcome after CRT for rectal cancer[50,51]. Some studies reported an improved prognosis after a longer CRT-surgery interval[42,52]. Tulchinsky et al[52] compared patients operated on at an interval of more or less than 7 wk after CRT. The longer-interval group had a significantly higher overall survival rate (93% vs 81%) and significantly lower distant metastasis rate (6% vs 19%) than the shorter-interval group. However, there was no between-group difference in local recurrence rate. Similarly, Coucke et al[42] demonstrated that delaying surgery for more than 5 d after hyperfractionated accelerated radiotherapy (41.6 Gy/26 Fx bid) led to a significantly higher rate of overall survival (69% vs 47% for < 5 d, P = 0.002), disease-free survival (62% vs 41%, P = 0.0003), and cancer-specific survival (82% vs 57%, P = 0.0007) at a median follow-up of 39 mo. In this study, too, there was no difference in local control rate between the groups. de Campos-Lobato et al[53] found a significant 3-year local recurrence benefit for delaying surgery for more than 8 wk after CRT (10.5% vs 1.2%), and Wolthuis et al[54] reported significantly improved 5-year cancer-specific survival (91% vs 83%) and recurrence-free survival (73% vs 83%) when CRT-surgery intervals were prolonged. Pach et al[55] randomized 154 patients to receive preoperative short-course radiation and surgery after 7 d vs surgery after 4-6 wk. Long CRT-surgery interval was associated with more tumor downstaging and tumor regression. Nevertheless, survival was similar in the two groups. On analysis of the oncological results of the Lyon R90-01 trial after a median follow-up of 6.3 years (range 6.1-7.2 years), Glehen et al[56] failed to find any significant between-group differences. These results were supported by a Korean study in which 397 patients were randomized to undergo surgery 28-41 or 42-59 d after long-course CRT[41]. Rates of local and distal recurrence and of overall survival were similar in the two groups. By contrast, a retrospective multivariate analysis of 102 patients with low rectal cancer demonstrated that delaying surgery beyond 16 wk from rectal cancer diagnosis had a negative impact on overall and metastasis-free survival (OR = 2.59; 95%CI: 1.33-5.79, P = 0.005)[57]. A long interval between radiation therapy and surgery (6-8 wk) was not recommended for patients who may not benefit from tumor downstaging by sphincter preservation.

Table 1 reviews the literature on the effect of a prolonged CRT-surgery interval on oncological outcome[28,36,38,40-44,49-52,54-62].

Table 1 Effect of chemoradiotherapy-surgery intervals on oncological outcome.
Ref.YearCRT-surgery intervalPts (n)pCRLROS
Francois et al[28] + Glehen et al[56]19992/6-8 wk2017%/14% NS13%/10%69%/66%
Stein et al[43]20034-8/10-143321%/14%NANA
Moore et al[44]2004 ≤ 44 d <15512%/19%NANA
Coucke et al[42]2006 ≤ 5 d <250NA10%/7%47%/69%2
Supiot et al[57]2006 ≤ 6 wk <102NA16%NA
Tran et al[40]2006 ≤ 8 wk <486%/9%0%/9%NA
Dolinsky et al[60]2007 ≤ 6-8 wk <107Same (P = 0.8)11%NA
Veenhof et al[62]20072/6-8 wk11080%/12%7%/2%64%/77%
Habr-Gama et al[61]2008 ≤ 12 wk <25010%/6%4NA3NA
Lim et al[41]200828-41/42-56 d39713.8%/15%8.2%3NA
Tulchinsky et al[52]2008 ≤ 7 wk <13217%/35%26%/4%81%/93%
Kerr et al[59]2008Median 76 d (6-215 d)18915.90%21%NA
de Campos-Lobato et al[53]2011 ≤ 8 wk <17716%/31%210.5%/1.2%NA
Garcia-Aguilar et al[38]20116/11 wk13618%/25%2NANA
Evans et al[58]2011 ≤ 6-8 wk <955%/12%/17%2NANA
Wolthuis et al[54]2012 ≤ 7 wk <35616%/28%26%/3%NA
Pach et al[55]20127-10 d/4-5 wk11540%/10.4%21.5%/7%63%/73%
Sloothaak et al[36]2013 ≤ 8 wk/8-9/10-11/11 <159310%/13%/18%2/11%NANA
EFFECT OF A PROLONGED CRT-SURGERY INTERVAL ON SURGICAL OUTCOME
Sphincter preservation

The benefit of preoperative CRT in increasing the sphincter preservation rate in patients with low-lying rectal cancer is controversial. The German CAO/ARO/AIO 94 Preoperative vs Postoperative Rectal Trial[11] reported that the preoperative administration of CRT led to a higher rate of sphincter preservation in clinical candidates for abdominoperineal resection. By contrast, a systematic review and meta-analysis of trials comparing preoperative radiation with preoperative chemoradiation showed that although preoperative CRT significantly increased the rate of pCR (P < 0.001), this did not translate into a higher rate of sphincter preservation (P = 0.29)[63]. The original Lyon R90-01 trial[28] suggested that extending the interval from CRT to surgery from 2 to 6 wk led to a trend of reduced rates of abdominoperineal resection in the longer-interval group. Yet in neither this study nor others that investigated sphincter preservation rates by CRT-surgery interval were the findings statistically significant[22,28,36].

Surgical difficulty and complications

Neoadjuvant radiotherapy for rectal cancer increases postoperative complications, predominantly because of an increased risk of anastomotic leaks and delayed perineal wound healing after abdominoperineal resection[31,64]. Delaying surgery after CRT is based on the rationale that it will allow more time for resolution of the acute inflammatory response to radiotherapy. At the same time, however, it could make dissection in the narrow pelvis more complex owing to the establishment of post-radiation fibrosis[58]. Garcia-Aguilar et al[38] examined the surgical difficulty and complication rate in 144 patients who underwent total mesorectal excision at 6 or 11 wk after CRT. The longer-interval group also received 2 cycles of modified FOLFOX-6 during the late resting period. There were no significant between-group differences in operative time, blood loss, or rates of diverting stoma, sphincter preservation, and R0 resection. Additionally, the proportion of patients who acquired any postoperative complications was similar in both groups (40%), with no significant difference in rate of anastomotic leaks. Surgeons participating in that study reported more widespread fibrosis in the longer-interval group. However, they were not blinded to the treatment protocol and ultimately rated surgical difficulty similarly (on a scale of 1-10) for both groups. Other authors, however, reported a longer operative time when the CRT-surgery interval was longer, which may reflect increased surgical difficulty[40,52]. Nonetheless, extending the CRT-surgery interval did not increase the complication rate[22]; indeed, one study noted significantly higher rates of anastomotic leak and perineal wound complications in patients in the shorter-interval (< 44 d) arm[59].

CONCLUSION

The traditional 6-wk CRT-surgery interval used for years in the treatment of rectal cancer was based primarily on a single study showing its oncological benefit compared to a 2-wk interval, which was apparently too short to yield significant post-radiation changes. Recent studies that sought to further improve outcome in patients with locally advanced, low-lying rectal tumors found that prolonging the interval beyond 6 wk was advantageous, mainly in terms of tumor downstaging and pCR rates, without increasing surgical difficulty or complications. These findings appear to have prompted a recent trend towards increasing the time from neoadjuvant CRT to surgery. However, the data available so far derive largely from retrospective studies that applied different CRT protocols and different CRT-surgery intervals, with no consideration of the effect of variability in preoperative staging. Further investigations with a higher level of evidence are required to definitively resolve this issue.

Several centers are currently conducting prospective randomized control studies to determine the optimal interval between CRT and surgery. The multicenter Swedish Stockholm III trial[65] that is testing different regimens of radiotherapy will be completed in 2018. Participants are divided into 3 groups: short-course CRT followed by surgery one week later; short-course CRT followed by surgery 4-8 wk later; and long-course CRT followed by surgery 4-8 wk later. The study will include an estimated 840 patients. An interim analysis of 303 patients showed that short-course CRT and surgery at 7-11 d was associated with a trend for more complications[66]. In another study begun in 2009 in the United Kingdom, patients are randomized to undergo CRT and surgery after 6 or 12 wk. The final cohort will include 218 patients at the end of recruitment[67]. Also from the United Kingdom, the STARRCAT Trial: Surgical Timing after Radiotherapy for Rectal Cancer[68], is a one-year pilot study assessing the same variables in addition to quality of life outcome. The findings will have important implications for the treatment of patients with rectal cancer.

Footnotes

P- Reviewers: Chen YJ, Kita H, Meshikhes AN, Stephane S, Wang XS S- Editor: Gou SX L- Editor: A E- Editor: Wu HL

References
1.  Jemal A, Siegel R, Xu J, Ward E. Cancer statistics, 2010. CA Cancer J Clin. 2010;60:277-300.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 10002]  [Cited by in F6Publishing: 10349]  [Article Influence: 739.2]  [Reference Citation Analysis (0)]
2.  Cohen SM, Neugut AI. Adjuvant therapy for rectal cancer in the elderly. Drugs Aging. 2004;21:437-451.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 10]  [Cited by in F6Publishing: 11]  [Article Influence: 0.6]  [Reference Citation Analysis (0)]
3.  Cellini F, Valentini V. Current perspectives on preoperative integrated treatments for locally advanced rectal cancer: a review of agreement and controversies. Oncology (Williston Park). 2012;26:730-735; 741.  [PubMed]  [DOI]  [Cited in This Article: ]
4.  Popek S, Tsikitis VL. Neoadjuvant vs adjuvant pelvic radiotherapy for locally advanced rectal cancer: Which is superior? World J Gastroenterol. 2011;17:848-854.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in CrossRef: 15]  [Cited by in F6Publishing: 15]  [Article Influence: 1.2]  [Reference Citation Analysis (0)]
5.  Du CZ, Chen YC, Cai Y, Xue WC, Gu J. Oncologic outcomes of primary and post-irradiated early stage rectal cancer: a retrospective cohort study. World J Gastroenterol. 2011;17:3229-3234.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in F6Publishing: 8]  [Reference Citation Analysis (0)]
6.  Petersen SH, Harling H, Kirkeby LT, Wille-Jørgensen P, Mocellin S. Postoperative adjuvant chemotherapy in rectal cancer operated for cure. Cochrane Database Syst Rev. 2012;3:CD004078.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 67]  [Cited by in F6Publishing: 122]  [Article Influence: 10.2]  [Reference Citation Analysis (0)]
7.  National Comprehensive Cancer Network NCCN Clinical Practice Guidelines in Oncology: Rectal cancer. Accessed: September, 26. 2013; Available from: http://www.tri-kobe.org/nccn/guideline/colorectal/english/rectal.pdf3:.  [PubMed]  [DOI]  [Cited in This Article: ]
8.  Peeters KC, Marijnen CA, Nagtegaal ID, Kranenbarg EK, Putter H, Wiggers T, Rutten H, Pahlman L, Glimelius B, Leer JW. The TME trial after a median follow-up of 6 years: increased local control but no survival benefit in irradiated patients with resectable rectal carcinoma. Ann Surg. 2007;246:693-701.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 853]  [Cited by in F6Publishing: 821]  [Article Influence: 48.3]  [Reference Citation Analysis (0)]
9.  Ortholan C, Francois E, Thomas O, Benchimol D, Baulieux J, Bosset JF, Gerard JP. Role of radiotherapy with surgery for T3 and resectable T4 rectal cancer: evidence from randomized trials. Dis Colon Rectum. 2006;49:302-310.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 58]  [Cited by in F6Publishing: 65]  [Article Influence: 3.6]  [Reference Citation Analysis (0)]
10.  Kim DW, Kim DY, Kim TH, Jung KH, Chang HJ, Sohn DK, Lim SB, Choi HS, Jeong SY, Park JG. Is T classification still correlated with lymph node status after preoperative chemoradiotherapy for rectal cancer? Cancer. 2006;106:1694-1700.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 59]  [Cited by in F6Publishing: 65]  [Article Influence: 3.6]  [Reference Citation Analysis (0)]
11.  Sauer R, Becker H, Hohenberger W, Rödel C, Wittekind C, Fietkau R, Martus P, Tschmelitsch J, Hager E, Hess CF. Preoperative versus postoperative chemoradiotherapy for rectal cancer. N Engl J Med. 2004;351:1731-1740.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 4342]  [Cited by in F6Publishing: 4228]  [Article Influence: 211.4]  [Reference Citation Analysis (1)]
12.  Kim DW, Lim SB, Kim DY, Kim TH, Jung KH, Kim DH, Chang HJ, Sohn DK, Hong CW, Choi HS. Pre-operative chemo-radiotherapy improves the sphincter preservation rate in patients with rectal cancer located within 3 cm of the anal verge. Eur J Surg Oncol. 2006;32:162-167.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 37]  [Cited by in F6Publishing: 39]  [Article Influence: 2.2]  [Reference Citation Analysis (0)]
13.  Capirci C, Valentini V, Cionini L, De Paoli A, Rodel C, Glynne-Jones R, Coco C, Romano M, Mantello G, Palazzi S. Prognostic value of pathologic complete response after neoadjuvant therapy in locally advanced rectal cancer: long-term analysis of 566 ypCR patients. Int J Radiat Oncol Biol Phys. 2008;72:99-107.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 323]  [Cited by in F6Publishing: 331]  [Article Influence: 20.7]  [Reference Citation Analysis (0)]
14.  Habr-Gama A, Perez RO, São Julião GP, Proscurshim I, Gama-Rodrigues J. Nonoperative approaches to rectal cancer: a critical evaluation. Semin Radiat Oncol. 2011;21:234-239.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 87]  [Cited by in F6Publishing: 92]  [Article Influence: 7.1]  [Reference Citation Analysis (0)]
15.  1 MERCURY Study Group. Diagnostic accuracy of preoperative magnetic resonance imaging in predicting curative resection of rectal cancer: prospective observational study. BMJ. 2006;333:779.  [PubMed]  [DOI]  [Cited in This Article: ]
16.  Supiot S, Gouraud W, Campion L, Jezéquel P, Buecher B, Charrier J, Heymann MF, Mahé MA, Rio E, Chérel M. Early dynamic transcriptomic changes during preoperative radiotherapy in patients with rectal cancer: a feasibility study. World J Gastroenterol. 2013;19:3249-3254.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in CrossRef: 27]  [Cited by in F6Publishing: 30]  [Article Influence: 2.7]  [Reference Citation Analysis (0)]
17.  Ozden SA, Ozyurt H, Ozgen Z, Kilinc O, Oncel M, Gul AE, Karadayi N, Serakinci N, Kan B, Orun O. Prognostic role of sensitive-to-apoptosis gene expression in rectal cancer. World J Gastroenterol. 2011;17:4905-4910.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in CrossRef: 6]  [Cited by in F6Publishing: 8]  [Article Influence: 0.6]  [Reference Citation Analysis (0)]
18.  Mohiuddin M, Winter K, Mitchell E, Hanna N, Yuen A, Nichols C, Shane R, Hayostek C, Willett C. Randomized phase II study of neoadjuvant combined-modality chemoradiation for distal rectal cancer: Radiation Therapy Oncology Group Trial 0012. J Clin Oncol. 2006;24:650-655.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 187]  [Cited by in F6Publishing: 190]  [Article Influence: 10.6]  [Reference Citation Analysis (0)]
19.  Wiltshire KL, Ward IG, Swallow C, Oza AM, Cummings B, Pond GR, Catton P, Kim J, Ringash J, Wong CS. Preoperative radiation with concurrent chemotherapy for resectable rectal cancer: effect of dose escalation on pathologic complete response, local recurrence-free survival, disease-free survival, and overall survival. Int J Radiat Oncol Biol Phys. 2006;64:709-716.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 81]  [Cited by in F6Publishing: 93]  [Article Influence: 4.9]  [Reference Citation Analysis (0)]
20.  Wong SJ, Winter K, Meropol NJ, Anne PR, Kachnic L, Rashid A, Watson JC, Mitchell E, Pollock J, Lee RJ. Radiation Therapy Oncology Group 0247: a randomized Phase II study of neoadjuvant capecitabine and irinotecan or capecitabine and oxaliplatin with concurrent radiotherapy for patients with locally advanced rectal cancer. Int J Radiat Oncol Biol Phys. 2012;82:1367-1375.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 49]  [Cited by in F6Publishing: 62]  [Article Influence: 4.8]  [Reference Citation Analysis (0)]
21.  Habr-Gama A, Perez RO, Sabbaga J, Nadalin W, São Julião GP, Gama-Rodrigues J. Increasing the rates of complete response to neoadjuvant chemoradiotherapy for distal rectal cancer: results of a prospective study using additional chemotherapy during the resting period. Dis Colon Rectum. 2009;52:1927-1934.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 161]  [Cited by in F6Publishing: 151]  [Article Influence: 10.1]  [Reference Citation Analysis (0)]
22.  Foster JD, Jones EL, Falk S, Cooper EJ, Francis NK. Timing of surgery after long-course neoadjuvant chemoradiotherapy for rectal cancer: a systematic review of the literature. Dis Colon Rectum. 2013;56:921-930.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 65]  [Cited by in F6Publishing: 73]  [Article Influence: 6.6]  [Reference Citation Analysis (0)]
23.  Kligerman MM, Urdaneta N, Knowlton A, Vidone R, Hartman PV, Vera R. Preoperative irradiation of rectosigmoid carcinoma including its regional lymph nodes. Am J Roentgenol Radium Ther Nucl Med. 1972;114:498-503.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 107]  [Cited by in F6Publishing: 106]  [Article Influence: 2.0]  [Reference Citation Analysis (0)]
24.  Rider WD, Palmer JA, Mahoney LJ, Robertson CT. Preoperative irradiation in operable cancer of the rectum: report of the Toronto trial. Can J Surg. 1977;20:335-338.  [PubMed]  [DOI]  [Cited in This Article: ]
25.  Higgins GA, Humphrey EW, Dwight RW, Roswit B, Lee LE, Keehn RJ. Preoperative radiation and surgery for cancer of the rectum. Veterans Administration Surgical Oncology Group Trial II. Cancer. 1986;58:352-359.  [PubMed]  [DOI]  [Cited in This Article: ]
26.  Gérard A, Buyse M, Nordlinger B, Loygue J, Pène F, Kempf P, Bosset JF, Gignoux M, Arnaud JP, Desaive C. Preoperative radiotherapy as adjuvant treatment in rectal cancer. Final results of a randomized study of the European Organization for Research and Treatment of Cancer (EORTC). Ann Surg. 1988;208:606-614.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 514]  [Cited by in F6Publishing: 492]  [Article Influence: 13.7]  [Reference Citation Analysis (0)]
27.  Randomized study on preoperative radiotherapy in rectal carcinoma. Stockholm Colorectal Cancer Study Group. Ann Surg Oncol. 1996;3:423-430.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 179]  [Cited by in F6Publishing: 171]  [Article Influence: 6.1]  [Reference Citation Analysis (0)]
28.  Francois Y, Nemoz CJ, Baulieux J, Vignal J, Grandjean JP, Partensky C, Souquet JC, Adeleine P, Gerard JP. Influence of the interval between preoperative radiation therapy and surgery on downstaging and on the rate of sphincter-sparing surgery for rectal cancer: the Lyon R90-01 randomized trial. J Clin Oncol. 1999;17:2396.  [PubMed]  [DOI]  [Cited in This Article: ]
29.  Wang Y, Cummings B, Catton P, Dawson L, Kim J, Ringash J, Wong R, Yi QL, Brierley J. Primary radical external beam radiotherapy of rectal adenocarcinoma: long term outcome of 271 patients. Radiother Oncol. 2005;77:126-132.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 60]  [Cited by in F6Publishing: 68]  [Article Influence: 3.6]  [Reference Citation Analysis (0)]
30.  Mohiuddin M, Mohiuddin MM, Marks J, Marks G. Future directions in neoadjuvant therapy of rectal cancer: maximizing pathological complete response rates. Cancer Treat Rev. 2009;35:547-552.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 16]  [Cited by in F6Publishing: 17]  [Article Influence: 1.1]  [Reference Citation Analysis (0)]
31.  Wong RK, Tandan V, De Silva S, Figueredo A. Pre-operative radiotherapy and curative surgery for the management of localized rectal carcinoma. Cochrane Database Syst Rev. 2007;CD002102.  [PubMed]  [DOI]  [Cited in This Article: ]
32.  Nozue M, Isaka N, Fukao K. Over-expression of vascular endothelial growth factor after preoperative radiation therapy for rectal cancer. Oncol Rep. 2001;8:1247-1249.  [PubMed]  [DOI]  [Cited in This Article: ]
33.  Baeten CI, Castermans K, Lammering G, Hillen F, Wouters BG, Hillen HF, Griffioen AW, Baeten CG. Effects of radiotherapy and chemotherapy on angiogenesis and leukocyte infiltration in rectal cancer. Int J Radiat Oncol Biol Phys. 2006;66:1219-1227.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 29]  [Cited by in F6Publishing: 36]  [Article Influence: 2.1]  [Reference Citation Analysis (0)]
34.  Dworak O, Keilholz L, Hoffmann A. Pathological features of rectal cancer after preoperative radiochemotherapy. Int J Colorectal Dis. 1997;12:19-23.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 995]  [Cited by in F6Publishing: 1015]  [Article Influence: 37.6]  [Reference Citation Analysis (1)]
35.  Rödel C, Martus P, Papadoupolos T, Füzesi L, Klimpfinger M, Fietkau R, Liersch T, Hohenberger W, Raab R, Sauer R. Prognostic significance of tumor regression after preoperative chemoradiotherapy for rectal cancer. J Clin Oncol. 2005;23:8688-8696.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 918]  [Cited by in F6Publishing: 923]  [Article Influence: 48.6]  [Reference Citation Analysis (0)]
36.  Sloothaak DA, Geijsen DE, van Leersum NJ, Punt CJ, Buskens CJ, Bemelman WA, Tanis PJ. Optimal time interval between neoadjuvant chemoradiotherapy and surgery for rectal cancer. Br J Surg. 2013;100:933-939.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 185]  [Cited by in F6Publishing: 197]  [Article Influence: 17.9]  [Reference Citation Analysis (0)]
37.  Kalady MF, de Campos-Lobato LF, Stocchi L, Geisler DP, Dietz D, Lavery IC, Fazio VW. Predictive factors of pathologic complete response after neoadjuvant chemoradiation for rectal cancer. Ann Surg. 2009;250:582-589.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 259]  [Cited by in F6Publishing: 267]  [Article Influence: 20.5]  [Reference Citation Analysis (0)]
38.  Garcia-Aguilar J, Smith DD, Avila K, Bergsland EK, Chu P, Krieg RM. Optimal timing of surgery after chemoradiation for advanced rectal cancer: preliminary results of a multicenter, nonrandomized phase II prospective trial. Ann Surg. 2011;254:97-102.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 219]  [Cited by in F6Publishing: 229]  [Article Influence: 17.6]  [Reference Citation Analysis (0)]
39.  Perez RO, Habr-Gama A, São Julião GP, Gama-Rodrigues J, Sousa AH, Campos FG, Imperiale AR, Lynn PB, Proscurshim I, Nahas SC. Optimal timing for assessment of tumor response to neoadjuvant chemoradiation in patients with rectal cancer: do all patients benefit from waiting longer than 6 weeks? Int J Radiat Oncol Biol Phys. 2012;84:1159-1165.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 55]  [Cited by in F6Publishing: 44]  [Article Influence: 3.7]  [Reference Citation Analysis (0)]
40.  Tran CL, Udani S, Holt A, Arnell T, Kumar R, Stamos MJ. Evaluation of safety of increased time interval between chemoradiation and resection for rectal cancer. Am J Surg. 2006;192:873-877.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 55]  [Cited by in F6Publishing: 64]  [Article Influence: 3.6]  [Reference Citation Analysis (0)]
41.  Lim SB, Choi HS, Jeong SY, Kim DY, Jung KH, Hong YS, Chang HJ, Park JG. Optimal surgery time after preoperative chemoradiotherapy for locally advanced rectal cancers. Ann Surg. 2008;248:243-251.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 91]  [Cited by in F6Publishing: 99]  [Article Influence: 6.2]  [Reference Citation Analysis (0)]
42.  Coucke PA, Notter M, Matter M, Fasolini F, Calmes JM, Schlumpf R, Schwegler N, Stamm B, Phuoc Do H, Bouzourene H. Effect of timing of surgery on survival after preoperative hyperfractionated accelerated radiotherapy (HART) for locally advanced rectal cancer (LARC): is it a matter of days? Acta Oncol. 2006;45:1086-1093.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 17]  [Cited by in F6Publishing: 16]  [Article Influence: 0.9]  [Reference Citation Analysis (0)]
43.  Stein DE, Mahmoud NN, Anné PR, Rose DG, Isenberg GA, Goldstein SD, Mitchell E, Fry RD. Longer time interval between completion of neoadjuvant chemoradiation and surgical resection does not improve downstaging of rectal carcinoma. Dis Colon Rectum. 2003;46:448-453.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 89]  [Cited by in F6Publishing: 89]  [Article Influence: 4.2]  [Reference Citation Analysis (0)]
44.  Moore HG, Gittleman AE, Minsky BD, Wong D, Paty PB, Weiser M, Temple L, Saltz L, Shia J, Guillem JG. Rate of pathologic complete response with increased interval between preoperative combined modality therapy and rectal cancer resection. Dis Colon Rectum. 2004;47:279-286.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 193]  [Cited by in F6Publishing: 200]  [Article Influence: 10.0]  [Reference Citation Analysis (0)]
45.  Sermier A, Gervaz P, Egger JF, Dao M, Allal AS, Bonet M, Morel P. Lymph node retrieval in abdominoperineal surgical specimen is radiation time-dependent. World J Surg Oncol. 2006;4:29.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 35]  [Cited by in F6Publishing: 39]  [Article Influence: 2.2]  [Reference Citation Analysis (0)]
46.  Bipat S, Glas AS, Slors FJ, Zwinderman AH, Bossuyt PM, Stoker J. Rectal cancer: local staging and assessment of lymph node involvement with endoluminal US, CT, and MR imaging--a meta-analysis. Radiology. 2004;232:773-783.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 727]  [Cited by in F6Publishing: 696]  [Article Influence: 34.8]  [Reference Citation Analysis (0)]
47.  Quirke P, Durdey P, Dixon MF, Williams NS. Local recurrence of rectal adenocarcinoma due to inadequate surgical resection. Histopathological study of lateral tumour spread and surgical excision. Lancet. 1986;2:996-999.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 1474]  [Cited by in F6Publishing: 1337]  [Article Influence: 35.2]  [Reference Citation Analysis (0)]
48.  Wibe A, Rendedal PR, Svensson E, Norstein J, Eide TJ, Myrvold HE, Søreide O. Prognostic significance of the circumferential resection margin following total mesorectal excision for rectal cancer. Br J Surg. 2002;89:327-334.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 482]  [Cited by in F6Publishing: 508]  [Article Influence: 23.1]  [Reference Citation Analysis (0)]
49.  Wasserberg N, Gutman H. Resection margins in modern rectal cancer surgery. J Surg Oncol. 2008;98:611-615.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 25]  [Cited by in F6Publishing: 28]  [Article Influence: 1.9]  [Reference Citation Analysis (0)]
50.  de Campos-Lobato LF, Stocchi L, da Luz Moreira A, Kalady MF, Geisler D, Dietz D, Lavery IC, Remzi FH, Fazio VW. Downstaging without complete pathologic response after neoadjuvant treatment improves cancer outcomes for cIII but not cII rectal cancers. Ann Surg Oncol. 2010;17:1758-1766.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 34]  [Cited by in F6Publishing: 40]  [Article Influence: 2.9]  [Reference Citation Analysis (0)]
51.  Maas M, Nelemans PJ, Valentini V, Das P, Rödel C, Kuo LJ, Calvo FA, García-Aguilar J, Glynne-Jones R, Haustermans K. Long-term outcome in patients with a pathological complete response after chemoradiation for rectal cancer: a pooled analysis of individual patient data. Lancet Oncol. 2010;11:835-844.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 1189]  [Cited by in F6Publishing: 1313]  [Article Influence: 93.8]  [Reference Citation Analysis (0)]
52.  Tulchinsky H, Shmueli E, Figer A, Klausner JM, Rabau M. An interval & gt; 7 weeks between neoadjuvant therapy and surgery improves pathologic complete response and disease-free survival in patients with locally advanced rectal cancer. Ann Surg Oncol. 2008;15:2661-2667.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 227]  [Cited by in F6Publishing: 242]  [Article Influence: 15.1]  [Reference Citation Analysis (0)]
53.  de Campos-Lobato LF, Geisler DP, da Luz Moreira A, Stocchi L, Dietz D, Kalady MF. Neoadjuvant therapy for rectal cancer: the impact of longer interval between chemoradiation and surgery. J Gastrointest Surg. 2011;15:444-450.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 97]  [Cited by in F6Publishing: 109]  [Article Influence: 8.4]  [Reference Citation Analysis (0)]
54.  Wolthuis AM, Penninckx F, Haustermans K, De Hertogh G, Fieuws S, Van Cutsem E, D’Hoore A. Impact of interval between neoadjuvant chemoradiotherapy and TME for locally advanced rectal cancer on pathologic response and oncologic outcome. Ann Surg Oncol. 2012;19:2833-2841.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 102]  [Cited by in F6Publishing: 113]  [Article Influence: 9.4]  [Reference Citation Analysis (0)]
55.  Pach R, Kulig J, Richter P, Gach T, Szura M, Kowalska T. Randomized clinical trial on preoperative radiotherapy 25 Gy in rectal cancer--treatment results at 5-year follow-up. Langenbecks Arch Surg. 2012;397:801-807.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 51]  [Cited by in F6Publishing: 46]  [Article Influence: 3.5]  [Reference Citation Analysis (0)]
56.  Glehen O, Chapet O, Adham M, Nemoz JC, Gerard JP. Long-term results of the Lyons R90-01 randomized trial of preoperative radiotherapy with delayed surgery and its effect on sphincter-saving surgery in rectal cancer. Br J Surg. 2003;90:996-998.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 82]  [Cited by in F6Publishing: 89]  [Article Influence: 4.2]  [Reference Citation Analysis (0)]
57.  Supiot S, Bennouna J, Rio E, Meurette G, Bardet E, Buecher B, Dravet F, Le Neel JC, Douillard JY, Mahé MA. Negative influence of delayed surgery on survival after preoperative radiotherapy in rectal cancer. Colorectal Dis. 2006;8:430-435.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 30]  [Cited by in F6Publishing: 33]  [Article Influence: 1.8]  [Reference Citation Analysis (0)]
58.  Evans J, Patel U, Brown G. Rectal cancer: primary staging and assessment after chemoradiotherapy. Semin Radiat Oncol. 2011;21:169-177.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 49]  [Cited by in F6Publishing: 54]  [Article Influence: 4.2]  [Reference Citation Analysis (0)]
59.  Kerr SF, Norton S, Glynne-Jones R. Delaying surgery after neoadjuvant chemoradiotherapy for rectal cancer may reduce postoperative morbidity without compromising prognosis. Br J Surg. 2008;95:1534-1540.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 91]  [Cited by in F6Publishing: 95]  [Article Influence: 5.9]  [Reference Citation Analysis (0)]
60.  Dolinsky CM, Mahmoud NN, Mick R, Sun W, Whittington RW, Solin LJ, Haller DG, Giantonio BJ, O’Dwyer PJ, Rosato EF. Effect of time interval between surgery and preoperative chemoradiotherapy with 5-fluorouracil or 5-fluorouracil and oxaliplatin on outcomes in rectal cancer. J Surg Oncol. 2007;96:207-212.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 43]  [Cited by in F6Publishing: 47]  [Article Influence: 2.8]  [Reference Citation Analysis (0)]
61.  Habr-Gama A, Perez RO, Proscurshim I, Nunes Dos Santos RM, Kiss D, Gama-Rodrigues J, Cecconello I. Interval between surgery and neoadjuvant chemoradiation therapy for distal rectal cancer: does delayed surgery have an impact on outcome? Int J Radiat Oncol Biol Phys. 2008;71:1181-1188.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 144]  [Cited by in F6Publishing: 151]  [Article Influence: 9.4]  [Reference Citation Analysis (0)]
62.  Veenhof AA, Bloemena E, Engel AF, van der Peet DL, Meijer OW, Cuesta MA. The relationship of histological tumor regression grade (TRG) and two different time intervals to surgery following radiation therapy for locally advanced rectal cancer. Int J Colorectal Dis. 2009;24:1091-1096.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 12]  [Cited by in F6Publishing: 13]  [Article Influence: 0.9]  [Reference Citation Analysis (0)]
63.  Ceelen W, Fierens K, Van Nieuwenhove Y, Pattyn P. Preoperative chemoradiation versus radiation alone for stage II and III resectable rectal cancer: a systematic review and meta-analysis. Int J Cancer. 2009;124:2966-2972.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 65]  [Cited by in F6Publishing: 78]  [Article Influence: 5.2]  [Reference Citation Analysis (0)]
64.  Påhlman L, Glimelius B. Pre- or postoperative radiotherapy in rectal and rectosigmoid carcinoma. Report from a randomized multicenter trial. Ann Surg. 1990;211:187-195.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 451]  [Cited by in F6Publishing: 411]  [Article Influence: 12.1]  [Reference Citation Analysis (0)]
65.  The Stockholm III Trial on Different Preoperative Radiotherapy Regimens in Rectal Cancer. Accessed: September, 26, 2013.  Available from: http://clinicaltrials.gov/show/NCT00904813.  [PubMed]  [DOI]  [Cited in This Article: ]
66.  Pettersson D, Cedermark B, Holm T, Radu C, Påhlman L, Glimelius B, Martling A. Interim analysis of the Stockholm III trial of preoperative radiotherapy regimens for rectal cancer. Br J Surg. 2010;97:580-587.  [PubMed]  [DOI]  [Cited in This Article: ]  [Cited by in Crossref: 185]  [Cited by in F6Publishing: 194]  [Article Influence: 13.9]  [Reference Citation Analysis (0)]
67.  Cancer Research United Kingdom Treatment for rectal cancer. Accessed: September, 26 2013;  Available from: http://www.cancerresearchuk.org/cancer-help/trials.  [PubMed]  [DOI]  [Cited in This Article: ]
68.  STARRCAT Trial: Surgical timing after radiotherapy for rectal cancer. Accessed: September, 26, 2013.  Available from: http://www.controlled-trials.com/ISRCTN88843062.  [PubMed]  [DOI]  [Cited in This Article: ]