Risk factors of positive resection margin differ in pancreaticoduodenectomy and distal pancreatosplenectomy for pancreatic ductal adenocarcinoma undergoing upfront surgery

Prognostic value of margin clearance in total and distal pancreatectomy specimens with pancreatic ductal adenocarcinoma in a Danish population-based nationwide study

BACKGROUND

The prognostic role of resection margin status following total (TP) and distal (DP) pancreatectomy for pancreatic ductal adenocarcinoma (PDAC) is insufficiently evaluated. In Denmark, pancreatic surgery, including the postoperative pathological examination of the resection specimens, is confined to four centres, all reporting to the Danish Pancreatic Cancer Database (DPCD). In this Danish population-based nationwide study on TP and DP for PDAC from 2015-2019, based on data from DPCD, we evaluated whether there is a prognostically relevant minimum margin clearance definition and whether certain margins hold independent prognostic information.

METHODS

Clinical and pathological data were retrieved from DPCD and supplemented by review of pathology reports and re-microscopy, if needed. One of the study pathologists performed all re-microscopy. The prognostic significance of margin status was evaluated by dichotomisation of the TP cohort (n = 101) and the DP cohort (n = 90) into involved and uninvolved groups, using different clearance definitions (0.5 - ≥3.0 mm).

RESULTS

Following TP, direct involvement of the superior mesenteric artery (SMA) margin had independent prognostic value. When using a clearance definition of ≥ 0.5 or ≥ 1.5 mm for SMA, median survival for R0 versus R1 was 19 (95% CI 14-26) versus 10 (95% CI 5-20) months (p = 0.010), and 21 (95% CI 15-30) versus 10 (95% CI 8-19) months (p = 0.011), respectively. Overall margin status was not of significant prognostic importance following neither DP nor TP.

CONCLUSION

In this Danish population-based nationwide study, SMA margin involvement was a significant isolated prognostic factor following TP, whereas combined assessment of all circumferential margins did not hold statistically significant prognostic information. Following DP, resection margin status did not affect survival.

Utility of intraoperative pathology consultations of whipple resection specimens and their impact on final margin status

The resection margin status is a significant surgical prognostic factor for the long-term outcomes of patients undergoing pancreaticoduodenectomy (Whipple procedure). As a result, surgeons frequently rely on intraoperative consults (IOCs) involving frozen sections to evaluate margin clearance during these resections. Nevertheless, the impact of this practice on final margin status and long-term outcomes remains a topic of debate. This study aimed to assess the impact of IOCs on the clearance rate of resection margins following Whipple procedure and distal pancreatectomy. A retrospective database review of all patients who underwent Whipple procedure or distal pancreatectomy at our institution between 2018 and 2020 was performed to evaluate the utility of IOCs by gastrointestinal surgeons and its correlation with final postoperative surgical margin status. A significant variation in the frequency of IOC requests for margins among surgeons was noted. However, the use of frozen section analysis for intraoperative margin assessment was not significantly associated with the clearance rate of final post-operative margins. More frequent use of IOC did not result in higher final margin clearance rate, an important prognostic factor following Whipple procedure.

A neoadjuvant therapy compatible prognostic staging for resected pancreatic ductal adenocarcinoma

OBJECTIVE

To improve prediction, the AJCC staging system was revised to be consistent with upfront surgery (UFS) and neoadjuvant therapy (NAT) for PDAC.

BACKGROUND

The AJCC staging system was designed for patients who have had UFS for PDAC, and it has limited predictive power for patients receiving NAT.

METHODS

We examined 146 PDAC patients who had resection after NAT and 1771 who had UFS at Changhai Hospital between 2012 and 2021. The clinicopathological factors were identified using Cox proportional regression analysis, and the Neoadjuvant Therapy Compatible Prognostic (NATCP) staging was developed based on these variables. Validation was carried out in the prospective NAT cohort and the SEER database. The staging approach was compared to the AJCC staging system regarding predictive accuracy.

RESULTS

The NAT cohort's multivariate analysis showed that tumor differentiation and the number of positive lymph nodes independently predicted OS. The NATCP staging simplified the AJCC stages, added tumor differentiation, and restaged the disease based on the Kaplan-Meier curve survival differences. The median OS for NATCP stages IA, IB, II, and III was 31.7 months, 25.0 months, and 15.8 months in the NAT cohort and 30.1 months, 22.8 months, 18.3 months, and 14.1 months in the UFS cohort. Compared to the AJCC staging method, the NATCP staging system performed better and was verified in the validation cohort.

CONCLUSIONS

Regardless of the use of NAT, NATCP staging demonstrated greater predictive abilities than the existing AJCC staging approach for resected PDAC and may facilitate clinical decision-making based on accurate prediction of patients' OS.

Risk factor analysis and a new prediction model of venous thromboembolism after pancreaticoduodenectomy

AIM

The present study aimed to identify risk factors for venous thromboembolism (VTE) after pancreaticoduodenectomy (PD) and to develop and internally validate a predictive model for the risk of venous thrombosis.

METHODS

We retrospectively collected data from 352 patients who visited our hospital to undergo PD from January 2018 to March 2022. The number of patients recruited was divided in an 8:2 ratio by using the random split method, with 80% of the patients serving as the training set and 20% as the validation set. The least absolute shrinkage and selection operator (Lasso) regression model was used to optimize feature selection for the VTE risk model. Multivariate logistic regression analysis was used to construct a prediction model by incorporating the features selected in the Lasso model. C-index, receiver operating characteristic curve, calibration plot, and decision curve were used to assess the accuracy of the model, to calibrate the model, and to determine the clinical usefulness of the model. Finally, we evaluated the prediction model for internal validation.

RESULTS

The predictors included in the prediction nomogram were sex, age, gastrointestinal symptoms, hypertension, diabetes, operative method, intraoperative bleeding, blood transfusion, neutrophil count, prothrombin time (PT), activated partial thromboplastin time (APTT), aspartate aminotransferase (AST)/alanine aminotransferase (ALT) ratio (AST/ALT), and total bilirubin (TBIL). The model showed good discrimination with a C-index of 0.827, had good consistency based on the calibration curve, and had an area under the ROC curve value of 0.822 (P < 0.001, 95%confidence interval:0.761-0.882). A high C-index value of 0.894 was reached in internal validation. Decision curve analysis showed that the VTE nomogram was clinically useful when intervention was decided at the VTE possibility threshold of 10%.

CONCLUSION

The novel model developed in this study is highly targeted and enables personalized assessment of VTE occurrence in patients who undergo PD. The predictors are easily accessible and facilitate the assessment of patients by clinical practitioners.