High-dose-rate surface brachytherapy as a treatment option for renal cell carcinoma cutaneous metastases

Introduction
The aim of this study was to present a case of complete clinical response of renal clear cell carcinoma cutaneous metastases after high-dose-rate surface brachytherapy (HDR sBT).

Material and methods
An 81-year-old female diagnosed with stage IV clear cell renal carcinoma reported to our center with painful relapse of two cutaneous metastases after a previous metastasectomy. The patient was disqualified from systemic therapy due to comorbidities, and qualified to attempt a treatment using HDR sBT. The unit equipped with an iridium-192 source was used to deliver 36 Gy/6 Gy in 6 fractions twice weekly. Overall treatment time was 18 days.

Results
Two weeks after HDR sBT, complete response was observed in one irradiated location, while the partial response was observed in the latter. EORTC grade 1 skin toxicity was reported in both irradiated fields. Three and five months after the treatment, the patient presented complete response and pain relief in both locations with no signs of relapse. The patient remained in palliative care and died seven months after the treatment due to sudden cardiac death.

Conclusions
HDR sBT can be a valuable treatment option for cutaneous metastatic renal cell carcinoma, especially for patients with significant comorbidities. The treatment provided was associated with low toxicity and excellent clinical outcome.