The aim of the study was to assess the feasibility and safety of stereotactic body radiotherapy (SBRT) in patients with advanced pancreatic adenocarcinoma.

We reviewed outcomes of 71 patients treated with SBRT for pancreatic cancer between July 2004 and January 2009. Forty patients (56%) had locally unresectable disease, 11 patients (16%) had local recurrence following surgical resection, 8 patients (11%) had metastatic disease, and 12 patients (17%) received adjuvant SBRT for positive margins. The median dose was 24 Gy (18-25 Gy), given in a single-fraction SBRT (n = 67) or fractionated SBRT (n = 4). Kaplan-Meyer survival analyses were used to estimate freedom from local progression (FFLP) and overall survival (OS) rates.

The median follow-up among surviving patients was 12.7 months (4-26 months). The median tumor volume was 17 mL (5.1-249 mL). The overall FFLP rates at 6 months/1 year were 71.7%/48.5%, respectively. Among those with macroscopic disease, FFLP was achieved in 77.3% of patients with tumor size <15 mL (n = 22), and 59.5% for ≥15 mL (n = 37) (P = 0.02). FFLP was achieved in 73% following 24 to 25 Gy, and 45% with 18 to 22 Gy (P = 0.004). The median OS was 10.3 months, with 6 month/1 year OS rates of 65.3%/41%, respectively. Grade 1-2 acute and late GI toxicity were seen in 39.5% of patients. Three patients experienced acute grade 3 toxicities.

SBRT is feasible, with minimal grade ≥3 toxicity. The overall FFLP rate for all patients was 64.8%, comparable to rates with external beam radiotherapy. This shorter treatment course can be delivered without delay in adjuvant systemic therapy.