Lymph node retrieval in pancreaticoduodenectomy specimens: does educating the pathologist matter?

Centralization of Pancreaticoduodenectomy: A Systematic Review and Spline Regression Analysis to Recommend Minimum Volume for a Specialist Pancreas Service

OBJECTIVE

Through a systematic review and spline curve analysis, to better define the minimum volume threshold for hospitals to perform (pancreaticoduodenectomy) and the high-volume center.

BACKGROUND

The pancreaticoduodenectomy (PD) is a resource-intensive procedure, with high morbidity and long hospital stays resulting in centralization towards high-volume hospitals; the published definition of high volume remains variable.

MATERIALS AND METHODS

Following a systematic review of studies comparing PD outcomes across volume groups, semiparametric regression modeling of morbidity (%), mortality (%), length of stay (days), lymph node harvest (number of nodes), and cost ($USD) as continuous variables were performed and fitted as a smoothed function of splines. If this showed a nonlinear association, then a "zero-crossing" technique was used, which produced "first and second derivatives" to identify volume thresholds.

RESULTS

Our analysis of 33 cohort studies (198,377 patients) showed 55 PDs/year and 43 PDs/year were the threshold value required to achieve the lowest morbidity and highest lymph node harvest, with model estimated df 5.154 ( P <0.001) and 8.254 ( P <0.001), respectively. The threshold value for mortality was ~45 PDs/year (model 9.219 ( P <0.001)), with the lowest mortality value (the optimum value) at ~70 PDs/year (ie, a high-volume center). No significant association was observed for cost ( edf =2, P =0.989) and length of stay ( edf =2.04, P =0.099).

CONCLUSIONS

There is a significant benefit from the centralization of PD, with 55 PDs/year and 43 PDs/year as the threshold value required to achieve the lowest morbidity and highest lymph node harvest, respectively. To achieve mortality benefit, the minimum procedure threshold is 45 PDs/year, with the lowest and optimum mortality value (ie, a high-volume center) at approximately 70 PDs/year.

At least 16 lymph nodes are recommended to examine during pancreaticoduodenectomy in ampullary adenocarcinoma

The minimum number of lymph nodes to be examined during pancreaticoduodenectomy (PD) for patients with ampullary adenocarcinoma (AC) is still debatable due to limited clinical data. Therefore, here we explored the relationship between the number of examined lymph node (ELN) and the current N staging (American Joint Committee on Cancer staging system, AJCC, 8 edition) after PD for AC as well as determined the minimum number of examined lymph nodes (MNELN) to ensure the accurate detection of nodal involvement. Patients underwent PD for AC in the National Cancer Center cohort of China (NCC cohort of China) from 1998 to 2020 and in the Surveillance, Epidemiology, and End Results database (SEER database) from 2010 to 2018 were retrospectively reviewed, and a total of 452 eligible patients were included in this study. The MNELN was evaluated by binomial probability law and best survival separation methods. Furthermore, the cut-off value of MNELN was validated in the NCC cohort of China using Least Absolute Shrinkage and Selection Operator (LASSO) regression. Our analysis indicated that the median number of ELN was 14, and the number of ELN was positively correlated with N stage. The MNELN was 16, whereas the best survival separation of ELN was 38 in node-positive patients and 3 in node-negative patients. In the validation cohort, the number of 16 ELNs was identified as a predictive variable for lymph node metastasis with nonzero coefficients in the LASSO-logistic regression model. Together, we concluded that a greater number of ELN was associated with more accurate nodal status assessment in PD for AC patients. A minimum of 16 lymph nodes were required to during PD in AC patients.

Reassessment of the Optimal Number of Examined Lymph Nodes in Pancreatoduodenectomy for Pancreatic Ductal Adenocarcinoma

OBJECTIVE

The aim of this study was to reappraise the optimal number of examined lymph nodes (ELNs) in pancreatoduodenectomy (PD) for pancreatic ductal adenocarcinoma (PDAC).

SUMMARY BACKGROUND DATA

The well-established threshold of 15 ELNs in PD for PDAC is optimized for detecting 1 positive node (PLN) per the previous 7th edition of the American Joint Committee on Cancer (AJCC) staging manual. In the framework of the 8th edition, where at least 4 PLN are needed for an N2 diagnosis, this threshold may be inadequate for accurate staging.

METHODS

Patients who underwent upfront PD at 2 academic institutions between 2000 and 2016 were analyzed. The optimal ELN threshold was defined as the cut-point associated with a 95% probability of identifying at least 4 PLNs in N2 patients. The results were validated addressing the N-status distribution and stage migration.

RESULTS

Overall, 1218 patients were included. The median number of ELN was 26 (IQR 17-37). ELN was independently associated with N2-status (OR 1.27, P < 0.001). The estimated optimal threshold of ELN was 28. This cut-point enabled improved detection of N2 patients and stage III disease (58% vs 37%, P = 0.001). The median survival was 28.6 months. There was an improved survival in N0/N1 patients when ELN exceeded 28, suggesting a stage migration effect (47 vs 29 months, adjusted HR 0.649, P < 0.001). In N2 patients, this threshold was not associated with survival on multivariable analysis.

CONCLUSION

Examining at least 28 LN in PD for PDAC ensures optimal staging through improved detection of N2/stage III disease. This may have relevant implications for benchmarking processes and quality implementation.

Incomplete surgical staging in clinical early-stage ovarian cancer: guidelines versus daily practice

Background

Incomplete surgical staging of patients with early-stage epithelial ovarian cancer (EOC) has been reported in up to 98% of cases, when based on the International Federation of Obstetrics and Gynecology (FIGO) staging procedure. The aim of the present retrospective study was to clarify the reasons for incomplete staging.

Methods

The PRISMA (Prevention Recovery Information System for Monitoring and Analysis) technique was used to evaluate cases with FIGO I-IIa EOC based on incomplete staging from five gynecologic oncologic center hospitals in the Netherlands in the period 2010-2014.

Results

Fifty cases with an incomplete surgical staging of EOC according to national guidelines were included. The most common reasons for incomplete staging were insufficient random biopsies of the peritoneum (n = 34, 68%), and less than ten lymph nodes being resected and/or found at pathology (n = 16, 32%). The most mentioned reason for not performing biopsies was, besides forgetting to do so, believing that after careful inspection and palpation, taking biopsies is irrelevant and/or already are being taken while performing a hysterectomy (peritoneum of cul-de-sac, bladder). The value of contralateral pelvic lymph node dissection in case of a unilateral ovarian malignancy was also doubted, influencing the number of lymph nodes resected.

Conclusions

The most important reasons for incomplete staging in EOC are, besides omitting elements by accident, questioning the importance of obligatory elements of the staging procedure. A structured list of staging steps during surgery and more evidence-based consensus concerning these obligatory elements might increase the number of complete staging procedures in EOC.

Propensity score-matching analysis comparing laparoscopic and open pancreaticoduodenectomy in elderly patients

There is little evidence on the safety and benefits of laparoscopic pancreaticoduodenectomy (LPD) in elderly patients; therefore, we evaluated the feasibility and efficacy of this procedure by comparing perioperative and oncological outcomes between LPD and open pancreaticoduodenectomy (OPD) in elderly patients. We retrospectively reviewed the data of 1,693 patients who underwent PD to manage periampullary tumours at a single institution between January 2014 and June 2017. Of these patients, 326 were elderly patients aged ≥70 years, with 56 patients allocated to the LPD group and 270 to the OPD group. One-to-one propensity score matching (56:56) was used to match the baseline characteristics of patients who underwent LPD and OPD. LPD was associated with significantly fewer clinically significant postoperative pancreatic fistulas (7.1% vs. 21.4%), fewer analgesic injections (10 vs. 15.6 times; p = 0.022), and longer operative time (321.8 vs. 268.5 minutes; p = 0.001) than OPD in elderly patients. There were no significant differences in 3-year overall and disease-free survival rates between the LPD and OPD groups. LPD had acceptable perioperative and oncological outcomes compared with OPD in elderly patients. LPD is a reliable treatment option for elderly patients with periampullary tumours.

Determining the Adequate Examined Lymph Node Count in Resected Ampullary Adenocarcinoma-A National Cohort Study

BACKGROUND

The evaluation of lymph node involvement is an essential component of cancer staging. Examining an inadequate number of lymph nodes potentially results in understaging. Current guidelines for lymph node retrieval for ampullary adenocarcinoma are based on data extrapolated from other periampullary malignancies and may not be applicable. The aim of this study was to determine the number of lymph nodes that should be examined in resection specimens to optimize staging in ampullary adenocarcinoma.

METHODS

Patients with ampullary adenocarcinoma from 2004 to 2014 were identified in the National Cancer Database. We determined the minimum examined lymph node (ELN) count by modeling each potential ELN count from 2 to 30 in a multivariable regression analysis and confirmed the results with a sensitivity analysis.

RESULTS

We identified 7451 patients of whom 52.2% had T3 or T4 disease and 51.4% had lymph node metastases. The median ELN count was 13 (interquartile range, 8-19). Increasing ELNs were independently associated with an increased likelihood of having positive nodal disease (odds ratio, 1.03; 95% confidence interval [CI], 1.03-1.04) and improved overall survival in both node-negative (hazard ratio [HR], 0.98; 95% CI, 0.97-0.99) and node-positive patients (HR, 0.99; 95% CI, 0.986-0.998). We determined that at least 17 lymph nodes should be examined. Overall survival for patients with 17 or more ELNs was superior than for those with fewer than 17 ELNs.

CONCLUSION

Increasing ELNs were independently associated with improved overall survival in patients with resected ampullary adenocarcinoma. At least 17 lymph nodes should be examined for optimal nodal staging.

How to Reliably Assess Nodal Status in Distal Pancreatectomy for Adenocarcinoma

OBJECTIVES

The optimal number of lymph nodes that need to be analyzed to reliably assess nodal status in distal pancreatectomy for adenocarcinoma is still unknown.

METHODS

Two hundred seventy-eight patients who underwent distal pancreatectomy for adenocarcinoma were retrieved from a retrospective French nationwide database. The relations between the number of analyzed lymph nodes and the nodal status of the tumor were studied. The beta-binomial law was used to estimate the probability of being truly node negative depending on the number of analyzed lymph nodes. Cox proportional hazard model was used for the survival analysis.

RESULTS

The median number of analyzed lymph nodes was 15. There was a positive correlation between the number of positive lymph nodes and the number of lymph nodes analyzed. The curve reached a plateau at approximately 25 lymph nodes. The beta binomial model demonstrated that an analysis of 21 negative lymph nodes shows a probability to be truly N0 at 95%. N+ status was associated with survival, but the number of lymph node analyzed was not.

CONCLUSION

At least 21 lymph nodes should be analyzed to ensure a reliable assessment of the nodal status, but this number may be hard to reach in distal pancreatectomy.

Evolution and impact of lymph node dissection during pancreaticoduodenectomy for pancreatic cancer

BACKGROUND

Insufficient examination of lymph nodes after pancreaticoduodenectomy can lead some pancreatic cancer patients with N1 disease to be misclassified as N0. We examined trends in lymph node dissection throughout time and investigated how these changes affect lymph node status and its prognostic value.

METHODS

The National Cancer Data Base was queried for patients with nonmetastatic pancreatic adenocarcinoma (2004-2013) who underwent classic pancreaticoduodenectomy with antrectomy. Logistic regression was performed for odds of node positivity. Kaplan-Meier curves and Cox proportional hazards models were used to assess the impact of lymph node status on overall survival for patients diagnosed during 2-year intervals from 2004-2012.

RESULTS

Median number of examined lymph nodes was 10 (interquartile range 6-15) in 2004 vs 17 (interquartile range 12-24) in 2013. Number of lymph nodes examined was a significant predictor of N1 disease (P < .0001), with a plateau at 30 nodes. N1 disease increased from 64.4% to 68.0% (P < .0001). Survival for both N1 and N0 subgroups improved. In successive multivariate models, N0 versus N1 status was consistently protective for overall survival (P < .0001), but there was no change in the magnitude of its hazard ratio over time (overall hazard ratio 0.691; 95% confidence interval 0.660-0.723).

CONCLUSION

Contemporary patients have an adequate number of nodes examined during standard pancreaticoduodenectomy. This, along with rising rates of N1 cancer detection and improved survival for both node-positive and node-negative patients, suggest more accurate classification of lymph node status. However, no increased benefit is achieved beyond 30 nodes. Overall, lymph node status remains a strong prognosticator for overall survival.

Factors predicting adequate lymph node yield in patients undergoing pancreatoduodenectomy for malignancy

Background

Most pancreatoduodenectomy resections do not meet the minimum of 12 lymph nodes recommended by the American Joint Committee on Cancer for accurate staging of periampullary malignancies. The purpose of this study was to investigate factors affecting the likelihood of adequate nodal yield in pancreatoduodenectomy specimens subject to routine pathological assessment.

Methods

Six hundred sixty-two patients subject to pancreatoduodenectomy between 1990 and 2013 for pancreatic, ampullary, and common bile duct cancers were reviewed. Predictors of yielding at least 12 lymph nodes were evaluated with a logistic regression model, and a survival analysis was carried out to verify the prognostic implications of nodal counts.

Results

The median number of evaluated nodes was 17 (interquartile range 11 to 25), and less than 12 lymph nodes were reported in surgical specimens of 179 (27 %) patients. Tumor diameter ≥20 mm (odds ratio [OR] 2.547, 95 % confidence interval [CI] 1.225 to 5.329, P = 0.013), lymph node metastases (OR 2.642, 95 % CI 1.378 to 5.061, P = 0.004), and radical lymphadenectomy (OR 5.566, 95 % CI 2.041 to 15.148, P = 0.01) were significant predictors of retrieving 12 or more lymph nodes. Lymph node counts did not influence the overall prognosis of the patients. However, a subgroup analysis carried out for individual cancer sites demonstrated that removing at least 12 lymph nodes is associated with better prognosis for pancreatic cancer.

Conclusions

Few variables affect adequate nodal yield in pancreatoduodenectomy specimens subject to routine pathological assessment. Considering the ambiguities related to the only modifiable factor identified, appropriate pathology training should be considered to increase nodal yield rather than more aggressive lymphatic dissection.