Dr. Kamran discusses oncologic outcomes for bladder-sparing treatments

In this video, Sophia C. Kamran, MD, discusses the oncologic outcomes associated with bladder preservation and trimodal therapy. Kamran is a radiation oncologist at the Massachusetts General Hospital Cancer Center and Assistant Professor of Radiation Oncology at Harvard Medical School, Boston, Massachusetts.

Transcription

What are the oncologic outcomes associated with bladder preservation and trimodal therapy and how do they compare with traditional radical cystectomy? The oncologic outcomes are excellent. That's why, in the [National Comprehensive CancerNetwork] guidelines, it's a category 1 recommendation for muscle-invasive bladder cancer, upthere with radical cystectomy. For long-term survivors, the bladder preservation rates are generally on the order of 70% or higher, which is excell nt. In terms of oncologic outcomes in terms of how they compare with traditional radical cystectomy, the best comparison would be to perform a randomized trial comparing radical cystectomy vs bladder-sparing therapy. Unfortunately, we're probably never going to be able to have that data. It was attempted before, and it just did not accrue. This was many years ago. Since that time, there have been lots of analyses comparing the outcomes between radical cystectomy and bladder preservation, usually looking at series. And from those older series, when you compare them head to head, which again, is not a perfect comparison, the oncologic outcomes appear to be equivalent, which is good. Most recently, in The Lancet Oncology, there was a large, retrospective, multi-institutional analysis published.¹ This included 722 patients with muscle-invasive urothelial carcinoma of the bladder. 440 received radical cystectomy and 282 received bladder-sparing treatment. The primary end point was metastasis-free survival, and then they also looked at other outcomes like overall survival, cancer-specific survival, and disease-free survival. They looked at survival outcomes using propensity scores, propensity score matching, and inverse probability treatment weighting. And so this is probably the best analysis that we're going to get aside from a randomized clinical trial, which we probably won't be able to see. The investigators found that in general, the 5-year metastasis-free survival was not significantly different between the 2 groups, and cancer-specific survival was not statistically different between the groups. Overall survival actually was slightly different in favor of bladder-sparing therapy—73.4% vs 66.5%. That was statistically significant. Again, because it's a retrospective analysis, even with all the matching and the inverse probability treatment weighting, it's hard to say definitively if that's something that is really there without that randomized clinical trial. But the fact that everything else looked very similar was extremely reassuring. Prior analyses that just compared radical cystectomy series and bladder preservation series had showed equivalency. But now we have this updated excellent data that were just published, showing that there's similar oncologic outcomes between the 2 treatments as well, which is very favorable and very exciting. So I would say that overall, the oncologic outcomes are equivalent between the 2 for well-selected patients.

Reference

1. Zlotta AR, Ballas LK, Niemierko A, et al. Radical cystectomy versus trimodality therapy for muscle-invasive bladder cancer: a multi-institutional propensity score matched and weighted analysis. Lancet Oncol. 2023;24(6):669-681. doi:10.1016/S1470-2045(23)00170-5

This transcript was edited for clarity.