Presentation Authors: Hiroshi Nakagomi*, Manabu Kamiyama, Takafumi Komiyama, Kan Marino, Shinnichi Aoki, Yoshiyasu Maehata, Norifumi Sawada, Takahiko Mitsui, Hiroshi Onishi, Masayuki Takeda, Chuo, Japan
Introduction: Some studies have reported positive outcomes of stereotactic body radiation therapy (SBRT) for the primary lesion of Renal cell carcinoma (RCC). SBRT is useful therapy for the elderly or inoperable patients in terms of its minimally invasiveness. However, little is known for long-term outcome. Here we show the safety and efficacy of SBRT for primary lesion of RCC with long-term and regular follow-up of tumor size and renal function.
Methods: This prospective study included 13 patients treated with SBRT for primary lesion of stage I RCC between August 2007 and June 2016 in our institution. Diagnosis of RCC was made by two radiologists using computed tomography (CT) or magnetic resonance imaging (MRI). A dosage of 60 Gy in 10 fractions or 70 Gy in 10 fractions was prescribed. The higher dose was selected if dose constraints were satisfied. Tumor response on imaging examination, local progression-free rate, overall survival, and toxicity were assessed.
Results: The mean follow-up period was 48.3 months (range: 11-108 months). The tumors showed very slow but continuous response during long-term follow up. Three cases (23.1%) showed transient progression during the short follow-up. The mean duration until the day on which partial response was confirmed among the partial or complete response cases was 22.6 months (95% CI: 15.3-30.0 months). Local progression-free rate was 92.3% for 3 years and overall survival rate 91.7% for 2 years and 71.3% for 3 years. Twelve cases (92.3%) had impaired renal function at baseline. Renal function decreased slowly and mildly in most of the cases, but two cases of solitary kidney showed grade 4 or 5 renal dysfunction.
Conclusions: All renal tumors decreased in size slowly but continuously for years after SBRT. Renal cancer can be treated radically with SBRT as a radio-sensitive tumor, but careful attention should be given in cases with solitary kidney.