Evaluating Tumor Regression and Survival Outcomes in Pancreatic Ductal Adenocarcinoma After Neoadjuvant Treatment according to CAP Grading System: Clinical Usefulness and Limitations.

Abstract

Neoadjuvant treatment (NAT) is increasingly employed for pancreatic ductal adenocarcinoma (PDAC), necessitating reliable methods to assess tumor response. The College of American Pathologists (CAP) grading system is widely used to predict chemo-responsiveness and survival, but consensus on the most effective grading system and treatment regimen remains elusive. This retrospective study included 462 patients with PDAC who underwent resection after NAT between 2009 and 2023. Survival outcomes were analyzed on the basis of CAP grades, and factors influencing favorable tumor responses were identified. Patients with CAP grades 0 and 1 showed significantly better overall survival (OS) and disease-free survival (DFS) than those with CAP grades 2 and 3. Key factors associated with improved outcomes included the 5-fluorouracil, irrinotecan, leucovorin, and oxaliplatin (FOLFIRINOX) regimen, stereotactic ablative body radiotherapy (SABR), and adjuvant chemotherapy. Despite achieving a pathological complete response, younger patients and those with pre-NAT suspected metastases were more prone to recurrence. CAP grade is a strong prognostic tool for PDAC after NAT. Survival outcomes are enhanced by FOLFIRINOX, SABR, and adjuvant chemotherapy. Ongoing adjuvant therapy and monitoring are crucial for younger patients or those with pre-NAT metastasis. Further studies should refine tumor grading systems and explore objective post-NAT evaluation methods.