Benefit of Whole-Pelvis Radiation for Patients With Muscle-Invasive Bladder Cancer: An Inverse Probability Treatment Weighted Analysis.

The value of pelvic lymph node irradiation is debated for patients with muscle-invasive bladder cancer (MIBC) undergoing curative-intent radiation therapy (RT). We sought to compare the oncological outcomes between bladder-only (BO)-RT and whole-pelvis (WP)-RT using a large Canadian multicenter collaborative database.

The study cohort consisted of 809 patients with MIBC (cT2-4aN0-2M0) who underwent curative RT at academic centers across Canada. Patients were divided into two groups on the basis of the RT volume: WP-RT versus BO-RT. Inverse probability of treatment weighting (IPTW) and absolute standardized differences (ASDs) were used to balance covariates across treatment groups. Regression models were used to assess the effect of the RT volume on the rates of complete response (CR), cancer-specific survival (CSS), and overall survival (OS).

After exclusion criteria, 599 patients were included, of whom 369 (61.6%) underwent WP-RT. Patients receiving WP-RT were younger (ASD, 0.41) and more likely to have an Eastern Cooperative Oncology Group performance status of 0-1 (ASD, 0.21), clinical node-positive disease (ASD, 0.40), and lymphovascular invasion (ASD, 0.25). In addition, WP-RT patients were more commonly treated with neoadjuvant chemotherapy (ASD, 0.29) and concurrent chemotherapy (ASD, 0.44). In the IPTW cohort, BO-RT and WP-RT groups were well balanced (all pretreatment parameters with an ASD <0.10). In multivariable analysis, WP-RT was not associated with CR rates post-RT (odds ratio, 1.14 [95 CI, 0.76 to 1.72]; P = .526) but was associated with both CSS (hazard ratio [HR], 0.66 [95% CI, 0.47 to 0.93]; P = .016) and OS (HR, 0.68 [95% CI, 0.54 to 0.87]; P = .002), independent of other prognostic factors.

Our study demonstrated that WP radiation was associated with better survival compared with bladder radiation alone after adjusted analysis. Additional randomized controlled trials are needed to confirm our findings.

Journal of clinical oncology : official journal of the American Society of Clinical Oncology. 2024 Oct 03 [Epub ahead of print]

Gautier Marcq, Ronald Kool, Alice Dragomir, Girish S Kulkarni, Rodney H Breau, Michael Kim, Ionut Busca, Hamidreza Abdi, Mark Dawidek, Michael Uy, Gagan Fervaha, Nimira Alimohamed, Jonathan Izawa, Claudio Jeldres, Ricardo Rendon, Bobby Shayegan, Robert Siemens, Peter C Black, Fabio L Cury, Wassim Kassouf

Department of Urology, McGill University Health Centre, Montreal, Canada., Department of Surgery (Urology), Princess Margaret Cancer Centre and the University Health Network, University of Toronto, Toronto, Canada., Division of Urology, The Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Canada., Department of Radiation Oncology, The Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Canada., Department of Urologic Sciences, University of British Columbia, Vancouver, Canada., Division of Urology, McMaster University, Hamilton, Canada., Department of Urology, Queen's University, Kingston, Canada., Division of Medical Oncology, University of Calgary, Calgary, Canada., Division of Urology, Western University, London, Canada., Division of Urology, University of Sherbrooke, Sherbrooke, Canada., Department of Urology, Dalhousie University, Halifax, Canada.