Purpose: To preliminarily evaluate the feasibility, therapeutic effect and toxicity of stereotactic gamma-ray body radiation therapy (γ-SBRT) for asynchronous bilateral renal cell carcinoma (bRCC).
Materials and methods: A retrospective analysis was performed on the clinical data of nine patients with asynchronous bRCC who were unable to undergo surgery and received γ-SBRT between February 2002 and May 2012. A total dose of 36-51 Gy was delivered to the 50 % isodose line covering the planning target volume at 3-5 Gy/fraction, whereas a total dose of 60-85 Gy was delivered at 5-7 Gy/fraction to the gross target volume. The local control rate (LC) and overall survival rate (OS) were calculated using the Kaplan-Meier method.
Results: Patient follow-up ended in March 2013 and the follow-up rate was 100 %. Of the nine patients, none presented with complete remission and five (55.6 %) achieved partial remission. The objective response rate was 55.6 %. The 1-, 3- and 5-year LC rates were 64.8, 43.2 and 43.2 %, respectively. The 1-, 3- and 5-year OS rates were 66.7, 53.3 and 35.6 %, respectively. Four (44.4 %) patients had an acute radiation reaction; there were two cases of grade I leukocytopenia and two cases of grade I gastrointestinal reactions. Late radiation-induced toxicity consisted of grade II gastrointestinal reactions in two patients.
Conclusion: Stereotactic gamma-ray body radiation therapy was found to be safe and effective in the treatment of asynchronous bRCC. Improved prognosis will require individualised treatment and a combination of multiple therapeutic approaches; this will be a primary research trend in the future.