Area of residual tumor (ART) can predict prognosis after post neoadjuvant therapy resection for pancreatic ductal adenocarcinoma

Satoshi Okubo,Yasuhiro Shimizu,Genichiro Ishii,Yoko Matsuda,Katsuhiko Uesaka,Masayoshi Hioki,Naoto Gotohda,Mari Mino-Kenudson,Motohiro Kojima,Soichiro Morinaga,Shinichiro Takahashi,Hirochika Toyama

doi:10.1038/s41598-019-53801-2

Abstract

An increasing number of patients with pancreatic ductal adenocarcinoma (PDAC) have undergone resection after neoadjuvant therapy (NAT). We have reported Area of Residual Tumor (ART) as a useful pathological assessment method to predict patient outcomes after post NAT resection in various cancer types. The aim of this study was to assess the prognostic performance of ART in PDAC resected after NAT. Sixty-three patients with PDAC after post NAT resection were analyzed. The viable residual tumor area was outlined and the measurement of ART was performed using morphometric software. The results were compared with those of the College of American Pathologist (CAP) regression grading. Of 63 cases, 39 (62%) patients received chemoradiation therapy and 24 (38%) received chemotherapy only. The median value of ART was 163 mm2. Large ART with 220 mm2 as the cut-off was significantly associated with lymphatic invasion, vascular invasion and perineural invasion, while CAP regression grading was not associated with any clinicopathological features. By multivariate analysis, large ART (≥220 mm2) was an independent predictor of shorter relapse free survival. Together with our previous reports, an ART-based pathological assessment may become a useful method to predict patient outcomes after post NAT resection across various cancer types.

Highlights

Pancreatic ductal adenocarcinoma (PDAC) is a lethal disease, and the clinical outcome is the worst among gastrointestinal cancers in the world[1]
An increasing number of pancreatic ductal adenocarcinoma (PDAC) have been surgically resected after Neoadjuvant therapy (NAT) in practice, and several phase II clinical trials of neoadjuvant chemoradiotherapy and chemotherapy have been conducted for borderline resectable and locally advanced PDACs, and even for resectable tumors[10,11,12,13,14,15,16]
We have reported area of residual tumor (ART) as a novel objective and quantitative pathological assessment method to evaluate the residual tumor in resections after NAT for gastric, lung and rectal cancers[29,30,31]

Summary

Introduction

Pancreatic ductal adenocarcinoma (PDAC) is a lethal disease, and the clinical outcome is the worst among gastrointestinal cancers in the world[1]. Pathological assessments on tumor regression or residual tumor in resections after NAT have been proven to be useful in predicting patient outcomes in many cancer types including rectal, lung, and esophageal cancers[20,21,22]. We have reported area of residual tumor (ART) as a novel objective and quantitative pathological assessment method to evaluate the residual tumor in resections after NAT for gastric, lung and rectal cancers[29,30,31]. No study has evaluated a role of ART in predicting outcomes of patients with PDAC after post NAT resection.

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Conclusion