CyberKnife Stereotactic Body Radiotherapy as a treatment option for renal cell carcinoma: The complex case of a patient with unilateral renal agenesis

Abstract

Surgery is the standard treatment for local renal cell carcinoma (RCC), but many patients are medically inoperable and local approaches such as radiofrequency ablation and cryoablation may be limited to smaller tumours. Conventional radiotherapy has not been effective in RCC, but higher dose-per-fraction radiotherapy has shown high local control rates accompanied by low toxicity. This is particularly important in the case of patients with a solitary kidney, either congenital or due to previous surgical history. Here, we present the case of a 68-year-old female patient with congenital right renal agenesis diagnosed with clear cell renal cell carcinoma in her left (solitary) kidney. Originally, the patient started treatment with sunitinib but 9 months later, due to important side effects, it was decided to treat her with CyberKnife Stereotactic Body Radiotherapy (SBRT) using a prescription dose of 45 Gy in five sessions. Ten months after her treatment, PET/CT images showed no signs of local hypermetabolism and more than a year after treatment, kidney function remains stable. Curiously, PET/CT also revealed the presence of percutaneous tumour seeding probably after renal biopsy. This case supports the growing body of evidence showing the value of Stereotactic Body Radiotherapy for renal cancer, especially for medically inoperable renal tumours in a solitary kidney.