Long-term outcomes of induction chemotherapy and neoadjuvant stereotactic body radiotherapy for borderline resectable and locally advanced pancreatic adenocarcinoma

Purpose. Limited data are available to guide neoadjuvant treatment of borderline resectable (BRPC) and locally advanced (LAPC) pancreatic cancer. Material and methods. We updated our institutional outcomes with a neoadjuvant chemotherapy and stereotactic body radiotherapy (SBRT) approach. An IRB-approved analysis was performed of all BRPC and LAPC patients treated with our departmental treatment protocol. After staging, medically fit patients underwent chemotherapy for 2-3 months, with regimen at the discretion of the treating medical oncologist. Patients then received SBRT delivered in five consecutive daily fractions with median total radiation doses of 30 Gy to tumor and 40 Gy dose painted to tumor-vessel interfaces. This was followed by restaging imaging for possible resection. Overall survival (OS), event free survival (EFS), and locoregional control (LRC) rates were estimated and compared by Kaplan-Meier and log-rank methods. Results. We identified 159 patients, 110 BRPC and 49 LAPC, with 14.0 months median overall follow-up. The resection and margin negative (R0) rate for BRPC patients who completed neoadjuvant therapy was 51% and 96%, respectively. Estimated median OS was 19.2 months for BRPC patients and 15.0 months for LAPC patients (p = 0.402). Median OS was 34.2 months for surgically resected patients versus 14.0 months for unresected patients (p < 0.001). Five of 21 (24%) LAPC patients receiving FOLFIRINOX chemotherapy underwent R0 resection. In LAPC, FOLFIRINOX recipients underwent R0 resection more often than other chemotherapy recipients (5 of 21 vs. 0 of 28, p = 0.011). There was a trend for improved survival in those resected LAPC patients (p = 0.09). For those not undergoing resection, one year LRC was 78%. Any grade >= 3 potentially radiation-related toxicity rate was 7%. Conclusions. These data underscore the feasibility, safety, and effectiveness of neoadjuvant SBRT and chemotherapy for BRPC and LAPC.