Radiation therapy may have benefit for NMIBC, but quality of current evidence is low

Of 13 studies evaluated by investigators for the meta-analysis, only 1 was a randomized controlled trial.

Radiation therapy may provide some benefit for patients with high-risk non–muscle invasive bladder cancer (NMIBC), but the quality of current evidence in this setting is low, investigators reported at the 2020 Society of Urologic Oncology Annual Meeting.1

For the study, investigators searched the Cochrane Central Register of Controlled Trials, EMBASE, MEDLINE, Scopus, and Web of Science for high-risk NMIBC treated with primary radiation therapy. The primary outcomes were recurrence-free survival (RFS), cancer-specific survival (CSS), overall survival (OS), and rates of salvage radical cystectomy and progression to metastatic disease.

Ultimately, the investigators’ search revealed 13 studies that met their search criteria, only 1 of which was a randomized controlled trial, with the remaining 12 studies being single institution and retrospective in nature.

From the 13 studies, the investigators derived the following 5-year rates of RFS, CSS, and OS: 54%, 86%, and 72%, respectively. In addition, 13% of patients underwent salvage cystectomy, and 9% developed metastatic disease.

Speaking with Urology Times®, study author Rodrigo R. Pessoa, MD, PhD, commented on the findings.

“Almost 80% of our patients will have a complete response with radiation for… high-grade disease. Unfortunately, around 10% of the patients will see [progression],” said Pessoa, urology resident at the University of Colorado Anschutz Medical Campus, Aurora.

Pessoa cautioned that the fact that only 1 randomized, controlled trial was included in their trial “is obviously a major limitation.”

“One other major limitation is that unfortunately, the randomized trial was not blinded,” Pessoa added.

Also discussing the findings with Urology Times®, senior author Simon P. Kim, MD, MPH, discussed the type of future research needed in this setting.

“In addition to answering the question about oncologic efficacy in terms of reducing the risk of relapse, it'd also be necessary to address the quality-of-life issue. Both BCG and radiation therapy may have quality-of-life implications. To date, we haven't had really good studies to evaluate and elucidate the quality-of-life implications not just for BCG but also for radiation therapy. I think a well-designed study that's a phase 3 trial [and is] multi-centered, that addresses the oncologic question… but also addresses the quality-of-life implications, potentially for both treatments, would be the ideal situation,” said Kim, associate professor of surgery-urology at the University of Colorado Anschutz Medical Campus.

Reference

1. Pessoa RR, Mueller A, Boxley P, et al. Systematic review and meta-analysis of radiation therapy for high-risk non-muscle invasive bladder cancer. Paper presented at: 2020 Society of Urologic Oncology Annual Meeting. December 2-5, 2020; virtual. Poster 34.