Can we downstage locally advanced pancreatic cancer to resectable? A phase I/II study of induction oxaliplatin and 5-FU chemoradiation.

BACKGROUND: Half of patients with pancreatic adenocarcinoma (PC) present with regionally advanced disease. This includes borderline resectable and locally advanced unresectable tumors as defined by current NCCN guidelines for resectability. Chemoradiation (CH-RT) is used in this setting in attempt to control local disease, and possibly downstage to resectable disease. We report a phase I/II trial of a combination of 5FU/Oxaliplatin with concurrent radiation in patients presenting with borderline resectable and locally advanced unresectable pancreatic cancer.
METHODS: Patients with biopsy-proven borderline resectable or locally advanced unresectable PC were eligible. Chemotherapy included continuous infusion 5FU (200 mg/m2) daily and oxaliplatin weekly for 5 weeks in dose escalation cohorts, ranging from 30 to 60 mg/m2. Concurrent radiation therapy consisted of 4,500 cGy in 25 fractions (180 cGy/fx/d) followed by a comedown to the tumor and margins for an additional 540 cGy ×3 (total dose 5,040 cGy in 28 fractions). Following completion of CH-RT, patients deemed resectable underwent surgery; those who remained unresectable for cure but did not progress (SD, stable disease) received mFOLFOX6 ×6 cycles. Survival was calculated using Kaplan-Meier analysis. End-points of the phase II portion were resectability and overall survival.
RESULTS: Overall, 24 subjects (15 men and 9 women, mean age 64.5 years) were enrolled between June 2004 and December 2009 and received CH-RT. Seventeen patients were enrolled in the Phase I component of the study, fifteen of whom completed neoadjuvant therapy. Reasons for not completing treatment included grade 3 toxicities (1 patient) and withdrawal of consent (1 patient). The highest dose of oxaliplatin (60 mg/m2) was well tolerated and it was used as the recommended phase II dose. An additional 7 patients were treated in the phase II portion, 5 of whom completed CH-RT; the remaining 2 patients did not complete treatment because of grade 3 toxicities. Overall, 4/24 did not complete CH-RT. Grade 4 toxicities related to initial CH-RT were observed during phase I (n=2, pulmonary embolism and lymphopenia) and phase II (n=3, fatigue, leukopenia and thrombocytopenia). Following restaging after completion of CH-RT, 4 patients had progressed (PD); 9 patients had SD and received additional chemotherapy with mFOLFOX6 (one of them had a dramatic response after two cycles and underwent curative resection); the remaining 7 patients (29.2%) were noted to have a response and were explored: 2 had PD, 4 had SD, still unresectable, and 1 patient was resected for cure with negative margins. Overall 2 patients (8.3%) in the study received curative resection following neoadjuvant therapy. Median overall survival for the entire study population was 11.4 months. Overall survival for the two resected patients was 41.7 and 21.6 months.
CONCLUSIONS: Combined modality treatment for borderline resectable and locally advanced unresectable pancreatic cancer with oxaliplatin, 5FU and radiation was reasonably well tolerated. The majority of patients remained unresectable. Survival data with this regimen were comparable to others for locally advanced pancreas cancer, suggesting the need for more novel approaches.