Palliative treatment of Kaposi sarcoma with radiotherapy: a single center experience

Purpose: The aim of this study is to evaluate the treatment responses of Kaposi sarcoma patients treated with radiotherapy (RT). Materials and Methods: The data of 18 patients (40 different regions) who were treated for Kaposi sarcoma in Department of the Radiation Oncology, Ankara City Hospital, Turkey between March 23, 2010 to February 13, 2018 were evaluated retrospectively. The primary endpoint of the study was the clinical-subjective response after RT, and the secondary endpoint was the visual response assessment after RT. Results: In evaluating the patients' reported response of the lesions: 25 (62.5%) of complete response (CR), 12 (30%) of partial response (PR), and stable response was seen in 3 patients (7.5%). Patient reported response after RT was significantly higher in male sex (p = 0.002; odds ratio [OR] = 13.8, 95% confidence interval [CI], 2.7-70.0). Physician reported response rates were available for 28 lesions and CR was detected in 12 lesions (30%); PR was observed in 16 (40%). The relationship between physician reported outcome and RT techniques (electron, bolus, or water bolus) is close to the limit of statically significance (p = 0.052). Fewer lesions disappeared in patients with photon preference than electrons (p = 0.036; OR = 0.093; 95% CI, 0.009-0.950). Patients' reported complete response rates were significantly higher in the 20 Gy per 5 fractions treatment arm (p = 0.042; OR = 1.75; 95% CI, 1.1-2.7). Conclusion: RT is an effective local treatment with high response rates in the treatment of Kaposi sarcoma. The subjective-clinical response rate was higher in male sex and the visual response was higher in the 20 Gy per 5 fractions arm. Additional studies are needed to standardize RT dose and techniques.