OA08) Pathologic Response to Neoadjuvant Chemotherapy and Chemoradiation in Borderline Resectable Adenocarcinoma of the Pancreas

We sought to investigate the efficacy of neoadjuvant chemotherapy (CT) followed by chemoradiation (CRT) followed by surgery in borderline resectable pancreatic cancer (BRPC). Fifteen patients with BRPC were identified. Borderline resectability was determined either radiographically, based on degree of vascular involvement and input from a surgical oncologist; or biochemically, based on CA 19-9 > 150 U/mL, all within a multidisciplinary tumor board setting. All patients had biopsy-proven adenocarcinoma. Staging workup included computed tomography of the chest, abdomen, and pelvis; endoscopic ultrasound, and laboratory studies including baseline CA 19-9. Patients received neoadjuvant CT followed by CRT (50.4 Gy in 28 fractions) given concurrently with capecitabine or gemcitabine. All patients underwent restaging prior to surgery. Pathologic response (PR) was graded by two independent pathologists specializing in GI malignancies according to the Modified Ryan Scheme for Tumor Regression Score. Univariate log-rank analyses were performed to identify predictors of progression-free survival and overall survival. Median age was 60 years (range, 45-77 years). Median CA 19-9 at diagnosis was 469 U/mL (range, < 18-2496 U/mL). All 15 patients successfully completed CRT as prescribed; only 1 patient (6%) experienced grade 2 GI toxicity, with no reported grade 3-4 GI toxicities. Median CA 19-9 following neoadjuvant therapy was 52 U/mL (range, < 18-463 U/mL). No disease progression was observed prior to surgery. R0 resection was possible in 14 patients (93%). Twelve patients (75%) achieved a partial PR to treatment. Only pretreatment CA 19-9 was associated with PR (p = 0.04). Eleven patients (73%) received adjuvant CT. Median progression-free survival and overall survival were 35 months and 36 months, respectively. Neoadjuvant CT followed by CRT was well-tolerated, and facilitated an R0 resection in 93% of patients with BRPC. Only pretreatment CA 19-9 was associated with PR (p = 0.04). Median overall survival was 36 months. These results warrant further investigation of neoadjuvant therapy in a larger cohort of patients.