A dose-response analysis for classical Kaposi's sarcoma management by radiotherapy

OBJECTIVE: To evaluate the dose-response relationship in classical Kaposi's sarcoma CKS patients treated with external beam radiotherapy.

METHODS: Between 1993 and 2004, patients with CKS treated at the Department of Radiation Oncology, Gulhane Military Medical School, Ankara, Turkey were evaluated in this retrospective study. The median age at initial presentation was 60 years. First, we analyzed the overall response rates for normalized total dose 2Gy NTD2Gy of <20 Gy, 20 Gy, and >20 Gy. Secondly, we searched for whether better response rates could be obtained with the NTD2Gy of >/=20 Gy compared to the NTD2Gy of <20 Gy.

RESULTS: There were 109 evaluable lesions in 18 patients. The median follow-up was 4 years. The overall response rates at the post-radiotherapy twelfth month were 88% for NTD2Gy of <20 Gy, 97% for 20 Gy, and 96% for NTD2Gy>20 Gy, which were not statistically different. The complete and partial response rates at 12 months were 93.2%, and 3.4% for NTD2Gy of >/=20Gy, and 64% and 24% for NTD2Gy of <20 Gy and these were statistically different p=0.001. Late side effects of radiation therapy were acceptable in all but 4 patients with fibrosis and edema.

CONCLUSION: This retrospective analysis showed that radiotherapy schedules with an NTD2Gy of 20 Gy and above by using local irradiation fields are effective in terms of complete response rates in the management of CKS compared to NTD2Gy of <20 Gy.