FOLFIRINOX and gemcitabine/nab-paclitaxel efficacy in the treatment of locally advanced unresectable pancreatic adenocarcinoma.

Abstract

399 Background: Locally advanced (LA) unresectable pancreatic adenocarcinoma (PDA) historically portends a poor prognosis with a median OS of 9-11 months. Recently, two multi-drug regimens – FOLFIRINOX and gemcitabine/nab-paclitaxel – have proven effective in the metastatic setting. We hypothesized that use of these regimens in the LA setting may improve survival. Methods: A retrospective review of a single institution’s cancer registry of all consecutive LA (unresectable) PDA patients between 2010 and 2014 was performed. LA status was verified by review of the triphasic, pancreas protocol CT scan at diagnosis using the 2015 NCCN criteria for resectability. Patients were divided into 4 groups: Group 1 = no therapy, Group 2 = “old” gemcitabine or 5-FU-based chemotherapy (CTX), Group 3 = “new” CTX (FOLFIRINOX and/or Gem/nab-paclitaxel), and Group 4 = resection after downstaging. Demographic, tumor related variables, and treatment outcomes were analyzed. Results: LA disease was verified in 107 consecutive patients. Median age was 69 years (range 36-92) and 50.5% were male. Median follow-up was 13.2 months (range 0.6-60.4). Median OS for Groups 1 (n=15), 2 (n=24), 3 (n=49), 4 (n=19) was 1.4, 11, 17.3, and 32 months respectively (p<0.001). On Cox multivariate regression (adjusted for age, sex, anatomic variables, and CA19-9 level at diagnosis), radiation (HR 0.44, p=0.003), older CTX (HR 0.16, p=0.007), newer CTX (HR 0.10, p=0.001), use of 2 or more lines of CTX (HR 0.16, p=0.022), CA19-9 decrease by >50% with any line of therapy (HR 0.31, p<0.001), and surgery (HR 0.28, p=0.002) were all significant predictors of OS in this cohort. On multivariate analysis between groups 2 and 3, newer CTX compared to older CTX (HR 0.490, p=0.02) and radiation (HR 0.510, p=0.015) provided an OS benefit. Conclusions: Compared to older CTX regimens, FOLFIRINOX and Gemcitabine/nab-paclitaxel improve survival in verified LA PDA patients. For the subset that ultimately undergoes resection, survival outcomes rival those of historically published resectable cohorts.