Stereotactic Ablative Radiotherapy for Treatment of Upper Urinary Tract Urothelial Carcinomas

Abstract

Urothelial carcinomas, also known as transitional cell carcinomas, account for more than 95% of upper urinary tract tumors. Radical nephroureterectomy is the gold-standard therapy for localized disease. There is scarce data on the use of modern radiotherapy for upper urinary tract urothelial carcinomas (UTUCs). The objective of this study is to present our experience with the treatment of this disease using Stereotactic Ablative Radiotherapy (SABR). A total of thirteen patients, five with primary transitional cell carcinoma (TCC) of the ureter and eight with primary or metastatic TCC of the renal pelvis, were treated with SABR and analyzed retrospectively. All patients were deemed not to be surgical candidates, and were thus treated with SABR to the site of macroscopic disease in the kidney or ureter. Normal tissue constraints were set as per Timmerman’s SABR-COMET trial constraints. Charts were reviewed for evaluation of symptoms and development of toxicity using the CTCAE v3.0, serum creatinine measurements as well as follow-up abdominal CT-scans and/or MRIs with RECIST criteria used to assess tumor response. Age at the time of treatment ranged from 65 to 95 years-old, with a median of 86 years-old. Most patients (7) received 40 Gy in 8 fractions every second day. Treatment was delivered with no undue complications. Follow-up ranged from 2 to 22 months, with a median of 8 months. Acutely, four patients presented with grade 1 diarrhea, and 1 patient presented with grade 1 hematuria. No chronic side effects were observed. Three patients had a complete response, seven patients had partial response, one had stable disease, and one had disease progression at the site of treatment. All patients remained free of obstructive symptoms. This small case series suggests that stereotactic ablative radiotherapy for upper urinary tract urothelial carcinomas is safe and well-tolerated, with good apparent tumor response to ablative doses of radiotherapy.