Meta-analysis of the efficacy of pancreatoduodenectomy with extended lymphadenectomy in the treatment of pancreatic cancer

Long-term outcomes of standard versus extended lymphadenectomy in pancreatoduodenectomy for pancreatic ductal adenocarcinoma: A Chinese multi-center prospective randomized controlled trial

INTRODUCTION

The value of extended lymphadenectomy in pancreatoduodenectomy (PD) has been discussed by five randomized controlled studies. However, the limitations in the studies made their conclusions not sufficiently reliable.

OBJECTIVES

This multi-center randomized controlled study was designed to clarify the efficacy of extended lymphadenectomy in PD for pancreatic ductal adenocarcinoma (PDAC).

METHODS

From December 2016 to October 2018, 170 consecutive patients undergoing PD were enrolled and randomized to standard or extended lymphadenectomy for the treatment of PDAC from three high-volume institutions in China. Demographic, pathological characteristics and survival data of these patients were collected and analyzed. No neoadjuvant treatment was performed. The primary endpoint was the 3-year overall survival.

RESULTS

For all patients, the 3-year survival rate was 25.88%. There was no between-group difference in 3-year survival rate (27.16% vs 24.72% p=0.717). The median survival time for the standard group was 18 months, while for the extended group it was 15 months. The demographic and pathological characteristics were similar between groups. More positive lymph nodes could be found in the extended group (2.34 ± 3.46 vs 1.41 ± 2.12, p=0.035), which led to nodule stage migration. All patients received chemotherapy. But patients in extended group were more likely to fail in completion of all-cycles chemotherapy before recurrence (31.46% vs 17.28%, p=0.032). Incomplete chemotherapy before recurrence, higher N status and abnormal CA125 were independent risk factors for 1-year survival (p<0.001, 95% CI 0.076-0.368; p=0.017, 95% CI 1.113-3.021; p=0.021, 95% CI 1.136-4.960, respectively), which was higher in the standard group (75.31% vs 58.43%, p=0.020).

CONCLUSION

The extended lymphadenectomy in PD did not improve the long-term survival in patients with PDAC. Patients with extended lymphadenectomy had a worse 1-year overall survival. However, the nodule stage migration facilitated by the extended lymphadenectomy contributed to the precise tumor staging.

Extended lymph node resection versus standard resection for pancreatic and periampullary adenocarcinoma

BACKGROUND

Pancreatic and periampullary adenocarcinomas account for some of the most aggressive malignancies, and the leading causes of cancer-related mortalities. Partial pancreaticoduodenectomy (PD) with negative resection margins is the only potentially curative therapy. The high prevalence of lymph node metastases has led to the hypothesis that wider excision with the removal of more lymphatic tissue could result in an improvement of survival, and higher rates of negative resection margins.

OBJECTIVES

To compare overall survival following standard (SLA) versus extended lymph lymphadenectomy (ELA) for pancreatic head and periampullary adenocarcinoma. We also compared secondary outcomes, such as morbidity, mortality, and tumour involvement of the resection margins between the two procedures.

SEARCH METHODS

We searched CENTRAL, MEDLINE, PubMed, and Embase from 1973 to September 2020; we applied no language restrictions.

SELECTION CRITERIA

Randomised controlled trials (RCT) comparing PD with SLA versus PD with ELA, including participants with pancreatic head and periampullary adenocarcinoma.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened references and extracted data from study reports. We calculated pooled risk ratios (RR) for most binary outcomes except for postoperative mortality, for which we estimated a Peto odds ratio (Peto OR), and mean differences (MD) for continuous outcomes. We used a fixed-effect model in the absence of substantial heterogeneity (I² < 25%), and a random-effects model in cases of substantial heterogeneity (I² > 25%). Two review authors independently assessed risk of bias, and we used GRADE to assess the quality of the evidence for important outcomes.

MAIN RESULTS

We included seven studies with 843 participants (421 ELA and 422 SLA). All seven studies included Kaplan-Meier curves for overall survival. There was little or no difference in survival between groups (log hazard ratio (log HR) 0.12, 95% confidence interval (CI) -3.06 to 3.31; P = 0.94; seven studies, 843 participants; very low-quality evidence). There was little or no difference in postoperative mortality between the groups (Peto odds ratio (OR) 1.20, 95% CI 0.51 to 2.80; seven studies, 843 participants; low-quality evidence). Operating time was probably longer for ELA (mean difference (MD) 50.13 minutes, 95% CI 19.19 to 81.06 minutes; five studies, 670 participants; moderate-quality evidence). There was substantial heterogeneity between the studies (I² = 88%; P < 0.00001). There may have been more blood loss during ELA (MD 137.43 mL, 95% CI 11.55 to 263.30 mL; two studies, 463 participants; very low-quality evidence). There was substantial heterogeneity between the studies (I² = 81%, P = 0.02). There may have been more lymph nodes retrieved during ELA (MD 11.09 nodes, 95% CI 7.16 to 15.02; five studies, 670 participants; moderate-quality evidence). There was substantial heterogeneity between the studies (I² = 81%, P < 0.00001). There was little or no difference in the incidence of positive resection margins between groups (RR 0.81, 95% CI 0.58 to 1.13; six studies, 783 participants; very low-quality evidence).

AUTHORS' CONCLUSIONS

There is no evidence of an impact on survival with extended versus standard lymph node resection. However, the operating time may have been longer and blood loss greater in the extended resection group. In conclusion, current evidence neither supports nor refutes the effect of extended lymph lymphadenectomy in people with adenocarcinoma of the head of the pancreas.

Optimal Range of Lymphadenectomy in Pathological Stage T1 and T2 Esophageal Squamous Cell Carcinoma

BACKGROUND

Lymph node metastasis is a primary contributor to tumor progression in esophageal squamous cell carcinoma (ESCC), and the optimal extent of lymphadenectomy during esophagectomy remains controversial. This study aimed to investigate the appropriate number of lymph nodes to be dissected in pT1-2Nany stage ESCC to achieve the best prognosis and avoid missing positive lymph nodes (PLNs).

METHODS

A total of 497 patients with pT1 to pT2 esophageal cancer from two institutions were retrospectively analyzed and their surgical and pathological records were critically reviewed. Stepwise analyses were conducted by calculating a serial of hazard ratios and odd ratios to determine the optimal range of lymphadenectomy for overall survival (OS).

RESULTS

The best survival outcome can be obtained when the number of lymph node examined (NLNE) is 10-18 in pT1N0 ESCC, while the NLNE should exceed 24 in pT2N0 diseases. In patients with pT1-2Nany and pT2Nany ESCC, resection of 15-25 and 24-37 lymph nodes, respectively, could provide significant added value for identifying positive nodal metastasis. When the NLNE exceeds this appropriate range, resection of extra lymph node is not helpful to improve the probability of finding PLNs.

CONCLUSIONS

For ESCC patients undergoing radical esophagectomy, the optimal extent of lymphadenectomy is 15-25 for pT1Nany disease and 24-37 for pT2Nany disease.

Meta-analysis and trial sequential analysis of randomised controlled trials comparing standard versus extended lymphadenectomy in pancreatoduodenectomy for adenocarcinoma of the head of pancreas

PURPOSE

To compare baseline demographics, operative, and survival outcomes of randomised controlled trials (RCTs) comparing standard lymphadenectomy versus extended lymphadenectomy in patients undergoing pancreaticoduodenectomy for pancreatic head cancer METHODS: In compliance with PRISMA standards we performed a meta-analysis of baseline demographics, operative, and survival outcomes of RCTs comparing standard lymphadenectomy versus extended lymphadenectomy in patients undergoing pancreaticoduodenectomy for pancreatic head cancer. The uncertainties associated with varying follow-up periods among the included studies were resolved by analysis of time-to-event outcomes. Moreover, we performed trial sequential analysis (TSA) to determine whether the available evidence is conclusive and to assess the risk of type 1 or type 2 errors.

RESULTS

Overall, 724 patients from 5 RCTs were included. The included populations were comparable in terms of baseline characteristics. There was no difference between standard and extended lymphadenectomy in terms of pancreatic fistula (OR 0.64, P = 0.11), delayed gastric emptying (OR 0.68, P = 0.40), bile leak (OR 0.33, P = 0.06), wound infection (OR 0.53, P = 0.06), abscess (OR 0.83, P = 0.63), total complications (OR 0.73, P = 0.27), postoperative mortality (OR 1.01, P = 0.85), and overall survival (HR 1.10, P = 0.46). TSA suggested that meta-analysis was conclusive with low risk of type 2 error. The results remained consistent through subgroup analyses based on lymph node positive or negative status and studies from the West and East.

CONCLUSIONS

Robust evidence from randomised controlled trials (Level 1) suggests no difference in postoperative and survival outcomes between standard and extended lymphadenectomy in patients undergoing pancreaticoduodenectomy for pancreatic head cancer. The findings were consistent in patients with positive and negative lymph node status and in studies from the West or East.

Para-aortic node involvement is not an independent predictor of survival after resection for pancreatic cancer

AIM

To analyze the importance of para-aortic node status in a series of patients who underwent pancreaticoduodenectomy (PD) in a single Institution.

METHODS

Between January 2000 and December 2012, 151 patients underwent PD with para-aortic node dissection for pancreatic adenocarcinoma in our Institution. Patients were divided into two groups: patients with negative PALNs (PALNs-), and patients with metastatic PALNs (PALNs+). Pathologic factors, including stage, nodal status, number of positive nodes and lymph node ratio, invasion of para-aortic nodes, tumor's grading, and radicality of resection were studied by univariate and multivariate analysis. Survival curves were constructed with Kaplan-Meier method and compared with Log-rank test: significance was considered as P < 0.05.

RESULTS

A total of 107 patients (74%) had nodal metastases. Median number of pathologically assessed lymph nodes was 26 (range 14-63). Twenty-five patients (16.5%) had para-aortic lymph node involvement. Thirty-three patients (23%) underwent R1 pancreatic resection. One-hundred forty-one patients recurred and died for tumor recurrence, one is alive with recurrence, and 9 are alive and free of disease. Overall survival was significantly influenced by grading (P = 0.0001), radicality of resection (P = 0.001), stage (P = 0.03), lymph node status (P = 0.04), para-aortic nodes metastases (P = 0.02). Multivariate analysis showed that grading was an independent prognostic factor for overall survival (P = 0.0001), while grading (P = 0.0001) and radicality of resection (P = 0.01) were prognostic parameters for disease-free survival. Number of metastatic nodes, node ratio, and para-aortic nodes involvement were not independent predictors of disease-free and overall survival.

CONCLUSION

In this experience, lymph node status and para-aortic node metastases were associated with poor survival at univariate analysis, but they were not independent prognostic factors.

The More the Better-Lower Rate of Stage Migration and Better Survival in Patients With Retrieval of 20 or More Regional Lymph Nodes in Pancreatic Cancer: A Population-Based Propensity Score Matched and Trend SEER Analysis

OBJECTIVE

The aim of this study was to assess the influence of regional lymph node (RLN) retrieval on stage migration and survival in pancreatic cancer.

METHODS

A total of 7685 stage I and II pancreatic cancer patients were identified in the Surveillance, Epidemiology, and End Results database in 2004-2011. The impact of RLN was assessed using Cox regression, propensity score methods, and joinpoint regression.

RESULTS

In 3079 patients, 1 to 10 RLNs were retrieved; in 2799 patients, 11 to 19 RLNs, and in 1807 patients, 20+ RLNs. The rate of node-positive pancreatic cancer increased with the number of retrieved RLN. This trend continued beyond 10 retrieved RLN (P < 0.001). In unadjusted analysis, retrieval of RLN did not influence survival (P = 0.178). When adjusting for significant bias in staging variables (P < 0.001), retrieval of 20+ RLNs compared to 11 to 19 RLNs was associated with an increased survival in node-negative (hazard ratio, 0.78; 95% confidence interval, 0.62-0.98; P = 0.033) and node-positive cancer (hazard ratio, 0.83; 95% confidence interval, 0.74-0.93; P = 0.002).

CONCLUSIONS

This population-based propensity score-adjusted investigation demonstrated that more retrieved RLNs in pancreatic cancer decreases the rate of stage migration and improves the oncological outcome in node-negative and positive cancer. Contradictory results may be explained by a bias in the cancer characteristics for a different extent of RLN retrieval.

Impact of margin status and lymphadenectomy on clinical outcomes in resected pancreatic adenocarcinoma: implications for adjuvant radiotherapy

BACKGROUND

Adjuvant chemoradiotherapy (CRT) in the treatment of pancreatic ductal adenocarcinoma (PDA) is controversial. Minimal data exists regarding the clinical significance of margin clearance distance and lymph node (LN) parameters, such as extent of dissection and LN ratio. We assessed the impact of these variables on clinical outcomes to more clearly define the subset of patients who may benefit from adjuvant radiotherapy (RT).

METHODS

We identified 106 patients with resected stage 1-3 PDA from 2007-2013. Resection margins were categorized as positive (tumor at ink), ≤1, or >1 mm. LN evaluation included total number examined (NE), number of positive nodes (NP), ratio of NP to NE (NR), extent of dissection, and positive periportal LNs. The impact of these variables was assessed on disease-free survival (DFS) and overall survival (OS) using multivariate cox proportional hazards modeling.

RESULTS

In patients receiving adjuvant chemotherapy (CT) alone, greater margin clearance led to improved DFS (P=0.0412, HR =0.51). Range of NE was 4-37, with a mean of 19. NE was not associated with DFS or OS, yet absolute NP of 5 or more was associated with a significantly worse DFS (P=0.005). Whereas periportal lymphadenectomy did not result in improved DFS or OS, patients with positive periportal LN had worse clinical outcomes (DFS, P=0.0052; OS, P=0.023). The use of adjuvant CRT was associated with improved OS (P=0.049; HR=0.29).

CONCLUSIONS

In patients receiving adjuvant CT alone, there was a clinically significant benefit to clearing the surgical margin beyond tumor at ink. Having ≥5 NP and positive periportal LN led to significantly worse clinical outcomes. The addition of adjuvant RT to CT in resected PDA improved OS. A comprehensive evaluation of resection margin distance and LN parameters may identify more patients at risk for locoregional failure who may benefit from adjuvant CRT.

Extended Versus Standard Lymphadenectomy for Pancreatic Head Cancer: Meta-Analysis of Randomized Controlled Trials

INTRODUCTION

The evidence for improved prognostic assessment and long-term survival for extended pancreatoduodenectomy (EPD) compared to standard pancreatoduodenectomy (SPD) in patients with carcinoma of the head of the pancreas has not been considered from only randomized controlled trials (RCTs).

METHODS

The aim of this study was to conduct a systematic review and meta-analysis of the outcomes comparing SPD and EPD in RCTs. Searches were performed on MEDLINE, Embase and Cochrane databases using MeSH keyword combinations: 'pancreatic cancer', 'pancreaticoduodenectomy', 'extended', 'randomized' and 'lymphadenectomy'. RCTs published up to 2014 were included. Overall post-operative survival, morbidity, 30-day mortality and length of hospital stay were the outcomes assessed.

RESULTS

Five eligible RCTs with 546 participants were included (EPD = 276 and SPD = 270). EPD was associated with a significantly higher number of excised lymph nodes (LNs) compared to SPD (mean difference = 15.73, 95% confidence interval (CI) = 9.41-22.04; P < 0.00001; I(2) = 88%). LN metastasis was detected in 58-68 and 55-70% of patients who had EPD and SPD, respectively. EPD did not improve overall survival (hazard ratio (HR) = 0.88, 95% CI = 0.75-1.03; P = 0.11) but did worsen post-operative morbidity compared to SPD (risk ratio (RR) = 1.23; 95% CI = 1.01-1.50; P = 0.004; I(2) = 9%). There were no differences in the 30-day mortality (RR = 0.81; 95% CI = 0.32-2.06; P = 0.66; I(2) = 0%) or length of hospital stay (mean difference = 1.39, 95% CI = -2.31 to 5.09; P = 0.46; I(2) = 67%).

CONCLUSION

SPD is associated with reduced morbidity, but equivalent long-term benefits compared to patients undergoing EPD.

Extent of lymphadenectomy to associate with pancreaticoduodenectomy in patients with pancreatic head cancer for better tumor staging

OBJECTIVES

To define the extent of lymphadenectomy to associate with surgery for pancreatic head cancer.

BACKGROUND

Pancreaticoduodenectomy with extended lymphadenectomy fails to prolong patient survival.

METHODS

Prospective randomized and nonrandomized controlled trials (RCTs and NRCTs), meta-analyses, retrospective reviews, consensus conferences and pre- and intraoperative diagnoses of lymph node (LN) metastases were retrieved. Standard and extended lymphadenectomies were reviewed, including their effects on postoperative complications, mortality rate and long-term survival. The minimum total number of LN examined (TNLE) for adequate tumor staging, and the incidence of metastasis to each LN station were also considered. A pros and cons analysis was performed on the removal of each LN station.

RESULTS

Eleven retrospective studies (2514 patients), five prospective NRCTs (545 patients), and five prospective RCTs (586 patients) described different lymphadenectomies, which obtained similar long-term results. Five meta-analyses showed they did not influence long-term survival. However, N status is an important component of tumor staging. The recommended minimum TNLE is 15. The percent incidence of metastasis to each LN station was calculated considering at least 385 and up to 3725 patients. Preoperative imaging and intraoperative exploration frequently fail to identify metastatic nodes. A pros and cons analysis suggests that lymph node status is better established removing the following LN stations: 6, 8a-p, 12a-b-c, 13a-b, 14a-b-c-d, 16b1, 17a-b. Metastasis to 16b1 LNs significantly worsens prognosis. Their removal and frozen section examination, before proceeding with resection, may contraindicate resection.

CONCLUSION

A standard lymphadenectomy demands an adequate TNLE and removal of the LN stations metastasizing more frequently, without increasing the surgical risk.

Mesopancreas: A boundless structure, namely the rationale for dissection of the paraaortic area in pancreaticoduodenectomy for pancreatic head carcinoma

This review highlights the rationale for dissection of the 16a2 and 16b1 paraaortic area during pancreaticoduodenectomy (PD) for carcinoma of the head of the pancreas. Recent advances in surgical anatomy of the mesopancreas indicate that the retropancreatic area is not a single entity with well defined boundaries but an anatomical site of embryological fusion of peritoneal layers, and that continuity exists between the neuro lymphovascular adipose tissues of the retropancreatic and paraaortic areas. Recent advances in surgical pathology and oncology indicate that, in pancreatic head carcinoma, the mesopancreatic resection margin is the primary site for R1 resection, and that epithelial-mesenchymal transition-related processes involved in tumor progression may impact on the prevalence of R1 resection or local recurrence rates after R0 surgery. These concepts imply that mesopancreas resection during PD for pancreatic head carcinoma should be extended to the paraaortic area in order to maximize retropancreatic clearance and minimize the likelihood of an R1 resection or the persistence of residual tumor cells after R0 resection. In PD for pancreatic head carcinoma, the rationale for dissection of the paraaortic area is to control the spread of the tumor cells along the mesopancreatic resection margin, rather than to control or stage the nodal spread. Although mesopancreatic resection cannot be considered “complete” or “en bloc”, it should be “extended as far as possible” or be “maximal”, including dissection of 16a2 and 16b1 paraaortic areas.