Background
Distal pancreatectomy (DP) is a major surgical procedure performed in patients with resectable pancreatic and tail tumors [
1]. However, when a pancreatic tissue that has not been infiltrated by the tumor is resected, DP often leads to impaired secretory function of the pancreas and poor long-term quality of life of patients [
2]. In 2003, Strasberg et al. introduced a new method of resection for pancreatic cancer (radical antegrade modular pancreatosplenectomy RAMPS) [
3]. Unlike DP which is performed from left to right, RAMPS is a novel procedure that includes a horizontal dissection plane from right to left and a radical resection of regional lymph nodes based on dissection of the pancreas. RAMPS is now widely performed, and it produces negative tangential edges and favorable survival rates [
4‐
6]. At present, the clinical outcomes of RAMPS have not been clearly defined. Most advanced studies on this topic are currently limited to single-center or small sample studies. Therefore, we conducted a systematic evaluation and meta-analysis to compare the results of distal pancreatectomy with those of radical anteroposterior modular pancreatoduodenectomy. The outcomes of this study are expected to guide further research and clinical selection of patients for surgery.
Discussion
Distal pancreatectomy (DP) was first proposed by the Mayo Clinic in 1913, which gradually became the standard surgical procedure for the body and tail of the pancreas [
16]. However, it has been found that the number of intraoperative lymph nodes dissected and the long-term survival rate of patients are small. This has remained to be a challenge despite the fact that surgeons have perfected this procedure and are more skilled in other surgical techniques. To overcome the shortcomings of the traditional DP, in 2003, Strasberg performed a complete resection of the tumor while ensuring sufficient negative margins and the removal of lymph nodes in the region. This radical resection of the pancreatic body cancer from right to left combined with the spleen is known as the radical antegrade modular pancreatosplenectomy (RAMPS). Among the RAMPS patients reported by Strasbourg, there were 9 cases with R0 resection and 9 cases with average lymph node clearance without death or other complications [
5]. By 2012, Strasberg and Fields had operated 80 RAMPS patients. The postoperative R0 excision rate was about 89%, and the 5-year survival rate increased from 26 to 35% [
4]. Currently, there are few studies examining postoperative complications and postoperative long-term survival quality of life after RAMPS and DP. Therefore, we systematically evaluated the differences in postoperative complications and postoperative long-term survival rate between RAMPS and DP to guide further research and clinical selection of patients for surgery.
The data reviewed showed that there were significant differences in operation time and intraoperative blood loss between RAMPS and DP (
P < 0.05). Postoperative pancreatic fistula, postoperative complications, postoperative hospital stay, and mortality were not statistically significant (
P > 0.05). The operation time of patients with RAMPS was relatively long, mainly because of pancreas and spleen movement, venous disconnection, local lymph node dissection, and posterior peritoneal tissue cleaning. Intraoperative blood loss was lower in RAMPS compared to DP. This may be due to the need to separate the pancreatic neck first, followed by a right to left surgery to effectively expose the surgical wound. Regarding postoperative complications, this study found no significant differences in the incidence of postoperative complications between the two groups. Pancreatic fistula is considered to be the most important postoperative complication and is a potentially serious, life-threatening event that can extend hospitalization and increase costs. Regardless of the technique used to cut and close the pancreatic stump, the reported occurrence rate of pancreatic fistula varies greatly from 2% to more than 20% [
17]. Although RAMPS is more difficult to perform than conventional surgery, it requires more retroperitoneal dissection, vascular nebulization, and lymph node dissection. However, the incidence of complications (pancreatic fistula) was not significantly different between RAMPS and DP. This proves that RAMPS is a safe and effective procedure.
The efficacy of RAMPS was mainly evaluated by pathological examination and long-term survival of patients after surgery. Pathological examination was assessed in terms of the rate of R0 excision and the number of lymph nodes resected. The results indicated that both the postoperative R0 resection rate and the number of lymph nodes resected were lower in DP group compared to RAMPS group, and the difference was statistically significant (P < 0.05). We postulate that these findings may be due to the following reasons: First, RAMPS is based on the anatomical architecture of the posterior pancreatic peritoneal fusion fascia (Gerota fascia, Treitz fascia, and Toldt fascia). Using Kocher approaches, the inferior vena cava and left renal vein along the Treitz fascia level; behind the Gerota fascia, the left renal vein, the renal capsule, and the left adrenal gland, are separated to achieve a complete resection of the nerve fiber connective tissue of the tail, spleen, and lymph nodes, enhancing the rate of R0 resection of the posterior peritoneum. In addition, RAMPS includes lymph node dissection based on the pattern of pancreatic lymphatic drainage to expose and clean all lymph nodes, which is difficult to achieve in traditional DP surgery.
Although there was no significant difference between RAMPS and DP in postoperative tumor recurrence (P > 0.05), there was a significant difference in long-term survival between the two groups (P<0.05). Studies have shown that RAMPS can prolong postoperative survival time compared with DP. In theory, RAMPS may reduce the local recurrence rate of tumors but not influence the systemic recurrence. However, based on our data, it is not easy to determine whether the local recurrence site is within the pancreatic stump, tumor bed or regional lymph node, making it difficult to determine the actual effect of RAMPS on tumor recurrence. We suggest that, when RAMPS relapse occurs, the time, location, frequency of recurrence and its effect on prognosis of the disease should be carefully monitored in future studies.
Our systematic review summarizes most of the available evidence in this regard. However, it has the following limitations: (1) although the included studies were of high-quality retrospective case-control studies, there was some deviations in patient selection; (2) the lack of randomness and retrospective studies introduces structural deviations that may lead to inaccurate data interpretation; (3) the postoperative management is different among different surgical centers, and the postoperative complications in patients are equally different; (4) the total number of cases in this study was small and there were regional differences. Therefore, large sample, multicenter, and standardized prospective randomized controlled trials are needed. The differences in postoperative complications and long-term survival were further discussed.
Our systematic review summarizes most of the available evidence in this field. However, it has the following limitations: (1) although the included articles were of high-quality retrospective case-control studies, some deviations in patient selection were apparent; (2) the lack of randomness and the retrospective nature of this study carries some structural deviations that may lead to inaccurate data analysis; (3) the postoperative management approaches were different among the surgical centers, and thus the postoperative complications in patients are expected to be different; (4) the total number of cases included in this study was relatively small and there were regional differences. Therefore, large sample, multicenter, and standardized prospective randomized controlled trials are needed to validate these findings. The differences in postoperative complications and long-term survival should be further evaluated.