Long-term outcomes after maximal surgical resection and intraoperative electron radiotherapy for locoregionally recurrent or locoregionally advanced primary renal cell carcinoma

Purpose: To report outcomes of a multimodality therapy combining maximal surgical resection and intraoperative electron radiotherapy (IOERT) for patients with locoregionally (LR) recurrent renal cell carcinoma (RCC) after radical nephrectomy or LR advanced primary RCC. Methods and Materials: From 1989 through 2005, a total of 22 patients with LR recurrent (n = 19) or LR advanced primary (n = 3) RCC were treated with this multimodality approach. The median patient age was 63 years (range 46-78). Twenty-one patients (95%) received perioperative external beam radiotherapy (EBRT) with a median dose of 4,500 cGy (range, 4,140-5,500). Surgical resection was R0 (negative margins) in 5 patients (23%) and R1 (residual microscopic disease) in 17 patients (77%). The median IOERT dose delivered was 1,250 cGy (range, 1,000-2,000). Overall survival (OS) and disease-free survival (DFS) and relapse patterns were estimated using the Kaplan-Meier method. Results: The median follow-up for surviving patients was 9.9 years (range, 3.6-20 years). The OS and DFS at 1, 5, and 10 years were 91%, 40%, and 35% and 64%, 31%, and 31%, respectively. Central recurrence (within the IOERT field), LR relapse (tumor bed or regional lymph nodes), and distant metastases at 5 years were 9%, 27%, and 64%, respectively. Mortality within 30 days of surgery and IOERT was 0%. Five patients (23%) experienced acute or late National Cancer Institute Common Toxicity Criteria (NCI-CTCAE) Version 4 Grade 3 to 5 toxicities. Conclusions: In patients with LR recurrent or LR advanced primary RCC, a multimodality approach of perioperative EBRT, maximal surgical resection, and IOERT yielded encouraging results. This regimen warrants further investigation.