Updated long-term outcomes after carbon-ion radiotherapy for primary renal cell carcinoma

The long-term oncologic outcomes for primary renal cell carcinoma (RCC) treated with carbon-ion radiotherapy (CIRT) are poorly understood. Patients with primary RCC were treated with 12/16-fraction CIRT at our institution outside of clinical trials. The outcome data were pooled and retrospectively analyzed for toxicity, local control, and disease-free, cancer-specific, and overall survival. From 1997 to 2014, 19 RCC patients (11 with T1aN0M0, 4 with T1bN0M0, and 4 with inoperable advanced stage [T4N0M0, T3aN1M0, and T1aN0M1]) were treated with CIRT and followed up for a median of 6.6 (range, 0.7-16.5) years; 9 of these patients were inoperable because of comorbidities or advanced-stage disease. The diagnoses were confirmed by imaging in 11 patients and by biopsy in the remaining 8. In four of five patients with definitive renal comorbidities, including diabetic nephropathy, sclerotic kidney, or solitary kidney pre-CIRT progressed to grade 4 chronic kidney disease (CKD). In contrast, the remaining 14 patients without definitive renal comorbidities did not progress to grade 3 or higher CKD. Furthermore, although one case of grade 4 dermatitis was observed, there were no other grade 3 or higher non-renal adverse events. The local control rate, and disease-free, cancer-specific, and overall survival rates at 5- years of all 19 patients were 94.1%, 68.9%, 100%, and 89.2%, respectively. This updated retrospective analysis based on long-term follow-up data suggests that CIRT is a safe treatment for primary RCC patients without definitive renal comorbidities pre-CIRT, and yielding favorable treatment outcomes, even in inoperable cases. This article is protected by copyright. All rights reserved.

Cancer science. 2018 Jul 07 [Epub ahead of print]

Goro Kasuya, Hiroshi Tsuji, Takuma Nomiya, Hirokazu Makishima, Yasuo Haruyama, Gen Kobashi, Daniel K Ebner, Kazuhiko Hayashi, Tokuhiko Omatsu, Riwa Kishimoto, Shigeo Yasuda, Tatsuo Igarashi, Mototsugu Oya, Koichiro Akakura, Hiroyoshi Suzuki, Tomohiko Ichikawa, Jun Shimazaki, Tadashi Kamada, Working Group for Genitourinary Tumors

Hospital of the National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan., Department of Radiology, Joban Hospital, Iwaki, Japan., Department of Public Health, Dokkyo Medical University, Tochigi, Japan., Department of Urology, Seirei Sakura Citizen Hospital, Chiba, Japan., Department of Urology, Keio University School of Medicine, Tokyo, Japan., Department of Urology, Japan Community Health Care Organization Tokyo, Shinjuku Medical Center, Tokyo, Japan., Department of Urology, Toho University Sakura Medical Center, Chiba, Japan.