Bladder Adjuvant Radiation Therapy (BART): Acute and Late Toxicity From a Phase III Multicenter Randomized Controlled...

Area of Science:

• Oncology
• Radiation Oncology
• Urothelial Carcinomas

Background:

• Muscle-invasive bladder cancer (MIBC) poses a significant treatment challenge.
• Adjuvant therapies are explored to improve outcomes after radical cystectomy.
• The role of adjuvant radiation therapy (RT) in high-risk MIBC remains under investigation.

Purpose of the Study:

• To evaluate the toxicity profile of adjuvant radiation therapy (RT) in the Bladder Adjuvant Radiation Therapy (BART) phase III trial.
• To compare acute and late toxicity between observation and adjuvant RT groups in patients with high-risk MIBC post-cystectomy.

Main Methods:

• Multicenter phase III randomized trial comparing observation (Obs) versus adjuvant intensity-modulated RT in high-risk MIBC patients.
• Patients with specific high-risk features post-radical cystectomy were randomized.
• Toxicity assessed using Common Terminology Criteria for Adverse Event v5.0; patients with early progression excluded from analysis.

Main Results:

• No significant difference in Grade 3 acute toxicity between RT and Obs groups (1.6% vs 4.2%).
• Higher Grade 2 acute toxicity observed in the RT arm, primarily gastrointestinal (17.5% vs 1.1%).
• Severe late toxicity (Grade 3-4) and cumulative Grade 2+ late toxicity were similar between the RT and Obs groups.

Conclusions:

• Adjuvant RT in high-risk MIBC following radical cystectomy demonstrated low and comparable severe acute and late toxicity to observation.
• The largest trial of its kind suggests adjuvant RT is a feasible option regarding toxicity.
• Oncological outcomes from the BART trial are anticipated to further inform treatment decisions.