PURPOSE: We retrospectively analyzed the impact of intraoperative radiation therapy (IORT) on long-term survival in patients with resectable gastric cancer. METHODS AND MATERIALS: From 1991 to 2001, a total of 84 patients with gastric neoplasms underwent gastectomy or subtotal resection with IORT (23 Gy, 6-15 MeV; IORT-positive [IORT(+)] group). Patients with a history of additional neoadjuvant chemotherapy, histologically confirmed R1 or R2 resection, or reoperation with curative intention after local recurrence were excluded from further analysis. The remaining 61 patients were retrospectively matched with 61 patients without IORT (IORT-negative [IORT(-)] group) for Union Internationale Contre le Cancer (UICC) stage, patient age, histologic grading, extent of surgery, and level of lymph node dissection. Subgroups included postoperative UICC Stages I (n = 31), II (n = 11), III (n = 14), and IV (n = 5). RESULTS: Mean follow-up was 4.8 years in the IORT(+) group and 5.0 years
in the IORT(-) group. The overall 5-year patient survival rate was 58% in the IORT(+) group vs. 59% in the IORT(-) group (p = 0.99). Subgroup analysis showed no impact of IORT on 5-year patient survival for those with UICC Stages I/II (76% vs. 80%; p = 0.87) and III/IV (21% vs. 14%, IORT(+) vs. IORT(-) group; p = 0.30). Perioperative mortality rates were 4.9% and 4.9% in the IORT(+) vs. IORT(-) group. Total surgical complications were more common in the IORT(+) than IORT(-) group (44.3% vs. 19.7%; p < 0.05). The locoregional tumor recurrence rate was 9.8% in the IORT(+) group. CONCLUSIONS: Use of IORT was associated with low locoregional tumor recurrence, but had no benefit on long-term survival while significantly increasing surgical morbidity in patients with curable gastric cancer.