Lymph node yield in rectal cancer surgery: Effect of preoperative chemoradiotherapy

doi:10.1016/j.ejso.2009.12.006

European Journal of Surgical Oncology (EJSO)

Volume 36, Issue 4, April 2010, Pages 345-349

https://doi.org/10.1016/j.ejso.2009.12.006 Get rights and content

Abstract

Aim

Adequate lymph node resection in rectal cancer is important for staging and local control. This study aims to verify the effect of neoadjuvant chemoradiation, as well as some clinicopathological features, on the yield of lymph nodes in rectal carcinoma.

Methods

Data on consecutive patients who had total mesorectal excision for rectal adenocarcinoma at a single cancer center between January 2003 and July 2008 were reviewed. No patient had any prior pelvic surgery or radiotherapy. Patients had neoadjuvant chemoradiotherapy if they were stage II or III.

Results

A total of 116 patients were included. The mean age was 53 years (range 29–83). Fifty-nine patients (51%) received neoadjuvant therapy before resection. The mean number of lymph nodes removed was 18 (range 4–67) per specimen. There was less lymph node yield in patients who received neoadjuvant therapy (16 vs. 19, p = 0.008). Only 64% of patients who had preoperative therapy had 12 lymph nodes or more in the specimen as opposed to 88% of those who had surgery upfront (p = 0.003). Other factors associated with lower lymph node yield included: female sex (p = 0.03) and tumour location in the lower rectum (p = 0.002). Age, tumour stage and grade, type of operation and surgical delay did not affect the number of lymph nodes removed.

Conclusion

Preoperative chemoradiotherapy for rectal cancer results in reduction in lymph node yield. Female sex and lower rectal tumours are also associated with retrieval of fewer lymph nodes.

Introduction

Pathological staging of colorectal cancer requires adequate resection of the tumour with the regional lymph nodes. In rectal carcinoma, this is achieved by total mesorectal excision (TME). Inadequate lymph node removal may result in understaging.

The National Cancer Institute (NCI) recommends that at least 12 lymph nodes are removed for adequate staging of colorectal cancer.¹ This is in accordance with the recommendations of the World Congress of Gastroenterology held in Sydney in 1990.² Removal of fewer lymph nodes results in understaging, and some patients who would benefit from receiving adjuvant therapy, therefore, would not be offered any.¹ Removal of fewer lymph nodes is also associated with a poorer survival and higher rates of local recurrence.3, 4, 5, 6 This is especially important for rectal cancer, as local recurrence is associated with significant morbidity.

Preoperative radiotherapy is thought to decrease the lymph node yield after surgical excision.7, 8, 9, 10 This is probably caused by the immune response and fibrosis in lymph nodes exposed to radiotherapy, which results in diminution in their size, making their identification in the pathology specimen difficult. This study aims to look at the effect of preoperative chemoradiotherapy (CRT) on the number of lymph nodes retrieved in the mesorectal specimen. Other clinicopathological factors are also studied.

Section snippets

Patient population

Data on all patients who had resection of rectal adenocarcinoma at a single cancer center were retrospectively reviewed. During the period from January 2003 to July 2008 a total of 134 cases met the inclusion criteria for this study. Their surgery was performed at the center by one of four surgeons who had previous training in proper rectal cancer surgery. All the patients had curative or potentially curative TME. Eighteen patients were excluded from the study because of previous pelvic surgery

Clinicopathological variables

The clinicopathological features are shown in Table 1. Out of the 116 patients, 61 were men and 55 were women with a mean age of 53 years (range 29–83). A little over half of the patients were over 50 years of age. All the tumours were adenocarcinomas and most of them were well or moderately differentiated (91%). Of the patients with a known pT stage, there was a predominance of T3 tumours (64%); the other stages were much less represented. Most tumours were in the lower two thirds of the

Adequate lymph node dissection

Adequate dissection of mesenteric lymph nodes in colorectal cancer is very important.¹ On the one hand, it provides adequate staging of the tumour, thus allowing proper prognostication and affects the decision to receive effective adjuvant treatment.3, 4, 6 It has been shown that the greater the number of lymph nodes removed, the higher the possibility of finding involved ones.11, 12 On the other hand, adequate resection of lymph nodes improves local control, decreases the incidence of local

Conclusion

In conclusion, preoperative CRT is associated with a reduction in the yield of lymph nodes in rectal cancer surgery. This is mainly related to radiotherapy, which exerts its' effects on the lymph nodes within the first few weeks of therapy. Other factors, such as sex and the level of the tumour, may also affect lymph node yield. All of these factors should be taken into consideration when evaluating the adequacy of lymph node resection in rectal carcinoma.

Conflict of interest statement

The authors have no conflict of interest to disclose.

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Extranodal extension (ENE) of nodal metastasis has emerged as an important prognostic factor in many malignancies, including rectal cancer. However, its significance in patients with rectal cancer receiving preoperative chemoradiotherapy (PCRT) has not been extensively investigated. We therefore assessed ENE and its prognostic impact in a large series of consecutive rectal cancer patients with lymph node metastasis after PCRT and curative resection.
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Citation Excerpt :
Obtaining an adequate LNY≥12 is important to avoid under-staging and stage migration of CRC which can affect whether AC is administered and alter long term prognosis.14,19 A number of studies have identified a diminished LNY in patients with rectal cancer who have received nCR.13,16,20-22 We identified this same trend within our cohort, which was particularly pronounced in patients with locally advanced disease.
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The National Cancer Database was used to identify patients with rectal adenocarcinomas from 2004 to 2014. Patients that received nCR were compared with those that underwent surgery alone. LNY was stratified into <12 and ≥12 groups to determine their differences in stage specific overall survival.
Of 56,812 patients 46.5% underwent surgery alone and 53.5% were administered nCR. There were more patients with LNY<12 in the nCR group compared to surgery alone, across all stages (44.1% versus 36.5%, P < 0.001). nCR improved OS regardless of LNY (P < 0.001). Although patients with LNY≥12 had improved overall survival, patients who had a pathologic complete response (pCR) achieved the greatest survival. In patients that did not achieve a pCR, LNY≥12 was a marker of improved OS but LNY did not impact OS in patients that attained pCR (P < 0.001).
Although nCR diminished LNY, LNY≥12 improved OS demonstrating the importance of quality total mesorectal excision. However, LNY did not impact patients that achieved pCR. These patients, who achieved the best OS, demonstrated that tumors' biologic response to nCR had the greatest impact on patient outcomes.
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Lymph node yield in rectal cancer surgery: Effect of preoperative chemoradiotherapy

Abstract

Aim

Methods

Results

Conclusion

Introduction

Section snippets

Patient population

Clinicopathological variables

Adequate lymph node dissection

Conclusion

Conflict of interest statement

Int J Radiat Oncol Biol Phys

Arch Med Res

Guidelines 2000 for colon and rectal cancer surgery

J Natl Cancer Inst

Clinicopathological staging for colorectal cancer: an International Documentation System (IDS) and an International Comprehensive Anatomical Terminology (ICAT)

J Gastroenterol Hepatol

Lymph node recovery from colorectal tumour specimens: recommendation for a minimum number of lymph nodes to be examined

World J Surg

Assessing the effectiveness of mesorectal excision in rectal cancer: prognostic value of the number of lymph nodes found in resected specimens

Dis Colon Rectum

Lymph node recoveries from 2427 pT3 colorectal resection specimens spanning 45 years: recommendations for a minimum number of recovered lymph nodes based on predictive probabilities

Am J Surg Pathol

Impact of number of nodes retrieved on outcome in patients with rectal cancer

J Clin Oncol

No downstaging after short-term preoperative radiotherapy in rectal cancer patients

J Clin Oncol

Macroscopic evaluation of rectal cancer resection specimen: clinical significance of the pathologist in quality control

J Clin Oncol

Short-term preoperative radiotherapy in rectal cancer patients leads to a reduction of the detectable number of lymph nodes in resection specimens

Langenbecks Arch Surg

Detection of lymph node metastases in colorectal carcinoma before and after fat clearance

Br J Surg

Colorectal adenocarcinoma: quality of the assessment of lymph node metastases

Dis Colon Rectum

Selection criteria for high risk and low risk groups of recurrence and metastasis in patients with primary colorectal cancer

Oncol Rep

For patients with Dukes' B (TNM Stage II) colorectal carcinoma, examination of six or fewer lymph nodes is related to poor prognosis

Cancer