Outcomes of radiation-based therapy (RT) for muscle-invasive bladder cancer (MIBC) with histologic subtypes of urothelial cancer (HS-UC) are lacking. Our objective was to compare survival outcomes of pure urothelial carcinoma (PUC) to HS-UC after RT.
A multicenter retrospective study of 864 patients with MIBC who underwent curative-intent RT to the bladder for MIBC (clinical T2-T4aN0-2M0) between 2001 and 2018 was conducted. Regression models were used to test the association between HS-UC and complete response (CR) and survival outcomes after RT.
In total, 122 patients (14%) had HS-UC. Seventy-five (61%) had HS-UC with squamous and/or glandular differentiation. A CR was confirmed in 69% of patients with PUC and 63% with HS-UC. There were 207 (28%) and 31 (25%) patients who died of metastatic bladder cancer in the PUC and HS-UC groups, respectively. There were 361 (49%) and 58 (48%) patients who died of any cause in the PUC and HS-UC groups, respectively. Survival outcomes were not statistically different between the groups. The HS-UC status was not associated with survival outcomes in multivariable Cox regression analyses.
In our study, HS-UC responded to RT with no significant difference in CR and survival outcomes compared to PUC. The presence of HS-UC in MIBC does not seem to confer resistance to RT, and patients should not be withheld from bladder preservation therapy options. Due to low numbers, definitive conclusions cannot be drawn for particular histologic subtypes.
The Journal of urology. 2024 Jul 25 [Epub ahead of print]
Daniel Halstuch, Ronald Kool, Gautier Marcq, Rodney H Breau, Peter C Black, Bobby Shayegan, Michael Kim, Ionut Busca, Hamidreza Abdi, Mark T Dawidek, Michael Uy, Gagan Fervaha, Fabio L Cury, Nimira S Alimohamed, Claudio Jeldres, Ricardo Rendon, Fadi Brimo, D Robert Siemens, Girish S Kulkarni, Wassim Kassouf, Jonathan I Izawa
Division of Urology, Western University, London, Ontario, Canada., Division of Urology, McGill University Health Center, Montreal, Quebec, Canada., Division of Urology, Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Ontario, Canada., Department of Urologic Sciences, University of British Columbia, Vancouver, British Columbia, Canada., Division of Urology, McMaster University, Hamilton, Ontario, Canada., Division of Urology, Department of Surgery, University of Toronto, Toronto, Ontario, Canada., Division of Radiation Oncology, Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Ontario, Canada., Department of Urology, Queen's University, Kingston, Ontario, Canada., Division of Medical Oncology, University of Calgary, Calgary, Alberta, Canada., Division of Urology, University of Sherbrooke, Sherbrooke, Quebec, Canada., Division of Urology, Dalhousie University, Halifax, Nova Scotia, Canada., Department of Pathology, McGill University Health Center, Montreal, Quebec, Canada.