Outcome of patients with pancreatic adenocarcinoma with complete pathological response following neo-adjuvant therapy

Abstract

Background: Recently, the natural history of metastatic pancreatic adenocarcinoma (PC) has changed after the introduction of new chemotherapeutical regimens FOLFIRINOX and gemcitabine/nab-paclitaxel, with median overall survival exceeding the year. These regimens were also largely prescribed in the neo-adjuvant setting for locally advanced (LAPC) and borderline (BPC) PC leading sometimes to a complete pathological response (CPR) rarely seen with previous neoadjuvant regimens. The aim of this study was to assess outcomes of patients (pts) who presented CPR after induction therapy for PC. Methods: We retrospectively identified pts with PC presenting CPR after neo-adjuvant therapy in 7 participating French centers from the AGEO group between November 2010 and March 2017. Results: 26 pts were enrolled, 12 had LAPC, 13 BPC and 1 oligo-metastatic PC; M/F ratio was 1.6 and mean age was 61 years. All pts were treated with neo-adjuvant FOLFIRINOX (n=26), de-escalated to gemcitabine (n=1) and FOLFIRI (n=2). The median number of cycles was 6 [4-24] and 85% of pts received neo-adjuvant radiation therapy after chemotherapy. Response to neo-adjuvant chemotherapy (RECIST V1.1), was as follow: CR 8%PR 57%, SD 27% and 8% were not evaluated. 30% of pts received adjuvant chemotherapy mainly with gemcitabine and 9 (35%) relapsed (distant metastases, n=8). Median time to recurrence in pts that replapsed was 12.9 months. After a median follow-up of 29.5months, the median overall survival (OS) from surgery was not reached and the median disease free survival was 38.8 months. The 1-year and 2- year OS rates were respectively 100% and 94%. The 1-year and 2-year DFS rates were 86% and 70%. Conclusions: CPR seem to be an important prognostic marker in pts resected of a PC after neo-adjuvant therapy. The limited recurrences rate and the 1 and 2-year OS and DFS rates are very promising. A longer follow-up and prospective series are now necessary to confirm the favorable outcomes of these PC with CPR.