Chemoradiation for resected pancreatic adenocarcinoma with or without intraoperative radiation therapy boost: Long-term outcomes

Abstract

Background/objectives: To analyze prognostic factors associated with long-term outcomes in patients with pancreatic cancer treated with chemoradiation therapy (CRT) and surgery with or without intraoperative electron beam radiotherapy (IOERT).

Patients and methods: From January 1995 to December 2012, 60 patients with adenocarcinoma of the pancreas and locoregional disease (clinical stage IB [n = 13; 22%], IIA [n = 16; 27%], IIB [n = 22; 36%], IIIC [n = 9; 15%]) were treated with CRT (45-50.4 Gy before surgery [n = 19; 32%] and after surgery [n = 41; 68%]) and curative resection (R0 [n = 34; 57%], R1 [n = 26, 43%]). Twenty-nine patients (48%) also received a pre-anastomosis IOERT boost (applicator diameter size, 7-10 cm; dose, 10-15 Gy; beam energy, 9-18 MeV).

Results: With a median follow-up of 15.9 months (range, 1-182), 5-year overall survival (OS), disease-free survival (DFS), and locoregional control were 20%, 13%, and 58%, respectively. Univariate analyses showed that R1 margin resection status (HR, 3.17; p = 0.04), not receiving IOERT (HR, 7.33; p = 0.01), and postoperative CRT (HR, 5.12; p = 0.04) were associated with a higher risk of locoregional recurrence. In the multivariate analysis, only margin resection status (HR, 3.0; p = 0.05) and not receiving IOERT (HR, 6.75; p = 0.01) retained significance with regard to locoregional recurrence. Postoperative mortality and perioperative complications were 3% (n = 2) and 43% (n = 26).

Conclusions: Although local control is good in the radiation-boosted area, OS remains modest owing to high risk of distant metastases. Intensified locoregional treatment needs to be tested in the context of more efficient systemic therapy.

Keywords: Intraoperative radiotherapy; Locoregional recurrence; Resected pancreatic cancer.