A Single Institution Review Of Efficacy Of Neoadjuvant Chemoradiation With Gemcitabine/Abraxane Compared to FOLFIRINOX in Pancreatic Ductal Adenocarcinoma

Abstract

FOLFIRINOX has improved OS in patients with metastatic pancreatic ductal adenocarcinoma (PDA) and as adjuvant therapy for resected PDA. No randomized data exists to support neoadjuvant chemoradiation (NA CRT) FOLFIRINOX over gemcitabine/abraxane (GA) although overall survival (OS), disease free survival (DFS), and R0 resection rates appear higher than historical data. A single institution retrospective review of all PDA patients from 2012-2020 who received NA CRT with gemcitabine/abraxane (GA) or FOLFIRINOX including those staged as borderline resectable (BR) or unresectable (UR) disease by the institutional tumor board at diagnosis. Information on demographics, cancer diagnosis, treatment, and outcomes were collected. Survival rates were determined by the Kaplan Meier method. At a median follow-up of 13.08 months, 51 PDA patients received NA CRT with GA (62%, n = 32) or FOLFIRINOX (37%, n = 19). The majority had BR disease (69%, n = 35/51), 20% (n = 10/51) had unresectable disease at diagnosis, 8% (n = 4/51) had resectable disease at diagnosis but were recommended NA CRT, and 4% (n = 2) had metastatic liver disease at diagnosis. Median age was higher in the GA group (66 years, range 46-82) compared to FOLFIRINOX (62 years, range 37-80). The FOLFIRINOX group had better performance status with 74% with ECOG 0-1 (n = 14/19) compared to GA with 47% (n = 15/32). Pre-treatment CA 19-9 was available for 42/51 pts with a median CA 19-9 of 188 (range 4-8736, n = 25/32) in GA vs 22 (range <1-2106, n = 17/19) in FOLFIRINOX, but this difference was non-significant (NS). The difference in median GTV was NS with 22.6 cm3 (range 3.2-59.2) in GA compared to 21.1 cm3 (range 3.2-90.7) in FOLFIRINOX and PTV dose coverage was 100% for all patients. All patients received pancreas SBRT with 3300 cGy/5 fractions. Radiographic progression 1 month after NA CRT was seen in 38% of the GA group (n = 12/32) compared to 21% with FOLFIRINOX (n = 4/19). Of note, 2 patients in the FOLFIRINOX group with liver metastases at diagnosis had complete regression of their lesions after starting chemotherapy. In non-metastatic patients, surgery was offered to 47% (n = 15/32) in GA compared to 26% (n = 5/19, 1 died prior to surgery) in FOLFIRINOX. Of those who had surgery, 73% (n = 11/15) had an R0 resection after NA GA with a 9% PCR (n = 1/11) compared to an R0 resection of 75% with FOLFIRINOX (n = 3/4, 1 had unresectable disease at surgery) and a pCR of 33% (1/3). Interestingly, there was 1 FOLFIRINOX patient with initially unresectable disease that proceeded to surgery with an R0 resection. There was no difference in OS or DFS between neoadjuvant GA (MS 20.3 months, median DFS 34.7) compared to FOLFIRINOX (MS 18 months, median DFS 35.4) in the entire cohort or in BR patients. In our institutional experience, we find that neoadjuvant FOLFIRINOX and gemcitabine/abraxane have similar treatment outcomes. FOLFIRINOX converted one unresectable patient to an R0 resection and caused regression of liver metastases in 2 patients.