Localized Radiotherapy for Classic Kaposi's Sarcoma: An Analysis of Lesion Characteristics and Treatment Response

Classic Kaposi's sarcoma (CKS) is a rare malignancy with diverse clinical presentations, lacking a standard treatment. While localized therapies are commonly used for symptomatic lesions, radiotherapy (RT) has demonstrated effectiveness. This study aims to evaluate the efficacy of RT for treating skin lesions in CKS.

A retrospective analysis was conducted on patients with KS treated between April 2012 and January 2024. In total, 69 lesions in 16 patients were included. Treatment response was defined as follows: complete response (CR) indicated the absence of clinically detectable skin lesions and symptoms; partial response (PR) was a reduction in lesion height by more than half or a lighter lesion color compared to before treatment. In-field recurrence was the appearance of new lesions within a previously irradiated field. Logistic regression analysis was used to investigate factors influencing response and in-field recurrence.

The median follow-up period was 52 months (range, 3-138 months). The overall response rate was 100%, with 92.8% of the patients achieving CR and 7.2% receiving PR. PR was observed in three patients with five lesions, all of which remained stable. In-field recurrence occurred in two patients with initially advanced disease, and all recurrent lesions responded to RT. No variables were significantly associated with response or in-field recurrence.

RT for CKS showed a 100% response rate, with complete symptom relief in all cases. The effectiveness of RT was evident, even in cases involving disseminated lesions. Further research is needed to determine the optimal RT dose and fractionation.