Squamous cell carcinoma (SCC) of the bladder is a rare subtype accounting for 2-5% of bladder cancers in Western countries. Its epidemiology, biological drivers, and clinical behavior differ substantially from urothelial carcinoma (UC), yet most management strategies remain extrapolated from UC due to the absence of dedicated evidence. Robust data are limited, and therapeutic decision-making is challenged by the rarity of this aggressive variant. Bladder SCC is strongly associated with chronic inflammatory conditions, including schistosomiasis, long-term catheterization, and recurrent urinary infections. Most patients present with muscle-invasive disease, characterized by marked local aggressiveness and a lower incidence of early nodal or distant metastases compared with UC. Molecular profiling indicates a predominant basal/squamous phenotype with frequent EGFR pathway activation and TP53/RB1 alterations, highlighting potential therapeutic vulnerabilities. However, the efficacy of perioperative chemotherapy, immunotherapy, or antibody-drug conjugates remains uncertain, as SCC patients are consistently underrepresented in clinical trials and outcomes are rarely reported separately. Emerging targeted strategies, such as Nectin-4 and Trop-2-directed agents, show promise but require prospective, SCC-specific evaluation. Bladder SCC remains an orphan malignancy with significant unmet clinical needs. Dedicated multicenter efforts are crucial to refine diagnostic pathways, integrate molecular characterization, and develop tailored therapeutic approaches. The French AVENTUR Group aims to address these gaps by coordinating national collaboration across institutions and promoting prospective clinical and translational research to improve outcomes in this rare and aggressive bladder cancer subtype.
Critical reviews in oncology/hematology. 2026 Jul 28 [Epub ahead of print]
Jérémy Mercier, Pierre Cornillon, Philippe Barthélémy, Priscilla Leon, Jacqueline Fontugne, Valentine Guimas, Wafa Bouleftour, Luc Olivier, Raafet Affi, Damien Pouessel, Stéphane Culine, Mathieu Roumiguié, Hakim Mahammedi, Constance Thibault, Fabien Moinard-Butot
Department of Urology, Kidney Transplantation and Andrology, TSA 50032 Rangueil Hospital, Toulouse Cedex 9, 31059, France., Department of Medical Oncology, North Hospital, CHU Saint Etienne, Saint Etienne, France., Department of Medical Oncology, Hôpitaux universitaires de Strasbourg, Strasbourg, France., Department of Urology, Clinique Pasteur, Royan, France., Department of Pathology, Institut Curie, Saint-Cloud, France., Department of Radiation Oncology, Institut de Cancérologie de l'Ouest, Saint-Herblain, France., Department of Medical Oncology, Centre d'Oncologie de Gentilly, Nancy, France., Univ Toulouse, Oncopole Claudius Regaud - IUCT-Oncopole, Department of Medical Oncology, Toulouse, France., Department of Medical Oncology, Hôpital Saint-Louis, AP-HP, Nord, Université de Paris Cité, Paris, France., Department of Urology, Clinique Pasteur, Toulouse, France., Department of Medical Oncology, Centre Jean Perrin, Clermont-Ferrand, France., Department of Medical Oncology, Hôpital Européen Georges Pompidou, Institut du Cancer Paris CARPEM, AP-HP Centre, Université de Paris Cité, Paris, France., Department of Medical Oncology, Hôpitaux universitaires de Strasbourg, Strasbourg, France. Electronic address: .