Intraoperative radiotherapy for the treatment of resectable locally advanced gastric adenocarcinoma: topography of locoregional recurrences and long-term outcomes

To report feasibility, tolerance, anatomical sites of upper abdominal locoregional recurrence and long-term outcome of gastric cancer patients treated with surgery and a component of intraoperative electron beam radiotherapy (IORT). From January 1995 to December 2010, 32 patients with primary gastric adenocarcinoma treated with curative resection (R0) [total gastrectomy (n = 9; 28 %), subtotal (n = 23; 72 %) and D2 lymphadenectomy in all patients] and apparent disease confined to locoregional area [Stage: II (n = 15; 47 %), III (n = 17; 53 %)] were treated with a component of IORT (IORT applicator size 5-9 cm in diameter, dose 10-15 Gy, beam energy 6-5 MeV) over the celiac axis and peripancreatic nodal areas. Sixteen (50 %) patients also received adjuvant treatment (external beam radiotherapy n = 6, chemoradiation n = 9, chemotherapy alone n = 1). With a median follow-up time of 40 months (range, 2-60), locoregional recurrence was observed in five (16 %) patients (4 nodal in hepatic hilum and 1 anastomotic). Only pN1 patients developed locoregional relapse. No recurrence was observed in the IORT-treated target volume (celiac trunk and peripancreatic nodes). Overall survival at 5 years was 54.6 % (95 % CI: 48.57-60.58). Postoperative mortality was 6 % (n = 2) and postoperative complications 19 % (n = 6). It is feasible to integrate IORT as a component of radiotherapy in combined modality therapy of gastric cancer. Local control is high in the radiation boosted area, but marginal regional extension (in particular, involving the hepatic hilum) might be considered as part of the anatomic IORT target volume at risk in pN+ patients.