Interpreting ART toxicity and tolerability for bladder cancer, with Vedang Murthy, MD

Adjuvant radiotherapy (ART) was not associated with a significantly greater risk of acute and late toxicity following radical cystectomy (RC) and chemotherapy in patients with muscle-invasive bladder cancer (MIBC), according to new findings from a phase 3 trial.

New data from the BART trial, presented in a late-breaking abstract session at the American Society for Radiation Oncology (ASTRO) 2024 Annual Meeting in Washington, DC, last week, showed that despite mild bowel toxicity occurring more frequently among patients receiving post-RC ART, the treatment method may be generally safe and tolerable for patients with MIBC. The trial is continuing to assess for oncological efficacy outcomes beyond the ASTRO 2024 data presentation, according to investigators.

In an interview with HCPLive during ASTRO 2024, study author Vedang Murthy, MD, professor of GU-Radiation Oncology at Tata Memorial Centre in Mumbai, India, discussed the significance of the BART trial findings, beginning with the fact that post-operative radiotherapy is not a highly common practice for MIBC.

“I think it comes from...a hardwired fear that radiation oncologists have, to treat the cystectomy bed, because there's a whole lot of bowel that is floating around there, and we are trained to not treat the bowel,” Murthy said. “So, when one looks at the bowel, one gets worried, and that's not just the (radiation oncologists).”

Much of this concern stems from education 10-20 years ago—a time when oncologists did not have adequate technology to safely treat the cystectomy bed, Murthy said. His team wanted to validate the modern safety of ART in post-cystectomy patients with MIBC in the trial. And indeed, the team reported that only up to 8% of patients reported toxicity after 2 years of follow-up with ART.

However, toxicity safety was a secondary outcome measure; Murthy and colleagues are continuing to assess BART patients for the primary outcome of improved disease control with ART.

“And that remains to be seen,” Murthy said. “There are some data coming from Egypt that it would be a good idea to (use adjunct) radiation, but I think over the next year or two, we will have enough events to show whether it helps outcomes or not.”

Murthy additionally discussed further analyses planned with the BART cohort, as well as the validation of safety and efficacy outcomes with consideration to patient-reported domains of bodily function after treatment and outcomes pertinent to quality of life.

References

^{Murthy V, Maitre P, Pal M, Sharma R, et al. LBA04 - Bladder Adjuvant RadioTherapy (BART): Acute and Late Toxicity from a Phase III Multicenter Randomized Controlled Trial. Session presented at: American Society for Radiation Oncology (ASTRO) 2024 Annual Meeting. Washington, DC. September 29 – October 2, 2024.}