Prospective evaluation of definitive chemoradiotherapy with volumetric modulated arc therapy in patients with muscle invasive carcinoma of urinary bladder

Introduction
Concurrent chemoradiotherapy (CTRT) remains one of the treatment options in patients with muscle invasive bladder cancer (MIBC) unwilling/unsuitable for radical surgery. We evaluated the role of volumetric modulated arc therapy (VMAT) in MIBC patients treated with definitive CTRT.

Material and methods
25 patients of histologically proven transitional cell MIBC (T2–T4a, N0, M0) unwilling/unsuitable for radical surgery (after maximal transurethral resection of bladder tumour) were recruited in this prospective study. Primary clinical target volume (CTV) consisted of the gross tumour and whole bladder. Primary planning target volume (PTV) and nodal PTV were prescribed 60 Gy and 54 Gy (both in 30 fractions). Concurrent chemotherapy was cisplatin (40 mg/m²) weekly. Acute toxicities were assessed as per Common Terminology Criteria for Adverse Events (CTCAE) version 4.0. Survival estimates were done from the date of registration using the Kaplan-Meier method.

Results
Median age was 70 years (37–80 years). Median overall treatment time was 45 days (44–51). Median number of chemotherapy cycles was 5 (range 3–6). 5 (20%) and 4 (16%) patients respectively suffered from acute grade ≥ 2 gastrointestinal and grade ≥ 2 genitourinary toxicities during treatment. One patient each had grade 3 anaemia and neutropenia. At a median follow-up of 34 months (10–45 months), 3-year progression-free survival and overall survival were 65.6% and 81.2% respectively. 3-year distant metastasis-free survival was 90.5%. Bladder preservation rate at 3 years was 68%.

Conclusions
Definitive CTRT with VMAT is well tolerated in patients with MIBC unsuitable for surgery and yields decent survival and bladder preservation outcome.