The therapeutic effect of stereotactic γ-ray body radiation therapy for patients with asynchronous bilateral renal cell carcinoma

Objective: To preliminarily evaluate the feasibility, therapeutic effect and normal tissue complications of stereotactic γ-ray body radiation therapy for patients with asynchronous bilateral renal cell carcinoma. Methods: Nine patients with inoperable asynchronous bilateral renal cell carcinoma with a median time from the resection of the primary focus and discovery of the contralateral focus underwent stereotactic γ-ray body radiotherapy with OUR-QGD stereotactic γ-ray whole body therapeutic planning system. 50% isodose line, as the prescription dose line, was to cover the planning target volume (PTV) and the 70% isodose line was to cover the gross target volume (GTV). Radiotherapy was delivered, with a single dose of 3-5 Gy per fraction, one fraction per day, 5 fractions per week, and totally 10-17 fractions. The PTV edge total dose was 36-51 Gy, and the GTV edge total dose was 60-85 Gy. The patients were followed up for a median time of 24 months to evaluate the local control rate and overall survival rate. Results: Of the 9 patients, 1 presented complete remission (11.1%) and 4 partial remission (44.5%), with a total effective rate of 55.6%. The 1-, 3-, and 5-year local control rates were 64.8%, 43.2%, and 43.2% respectively. The 1-, 3-, and 5-year overall survival rates were 66.7%, 53.3%, and 35.6% respectively. Four patients (44.4%) had acute radiation reaction: 2 cases with grade 1 leukocytopenia and 2 cases with grade 1 gastrointestinal reactions. Two patients showed grade 2 late radiation-induced reaction in gastrointestinal system. The Karnofsky score was significantly increased and the renal function was normal after radiotherapy. Conclusions: Stereotactic γ-ray body radiation therapy is safe and effective in the treatment of asynchronous bilateral renal cell carcinoma. (authors)