Will the Use of Biomarkers Improve Bladder Cancer Radiotherapy Delivery?

Bladder Cancer Treatments in the Age of Personalized Medicine: A Comprehensive Review of Potential Radiosensitivity Biomarkers

Bladder cancer is one of the most frequently diagnosed cancers in men. While cystectomy remains the primary treatment, advances in radiotherapy and chemotherapy have highlighted the value of bladder-preserving strategies, which can also enhance patients' quality of life. Despise these advances, around 20% of patients may still require salvage cystectomy due to tumor radioresistance. This underscores the need to develop radiosensitivity predictive assays. Radiotherapy acts by inducing DNA damage, primarily through DNA double-strand breaks, which can significantly affect treatment outcomes if left unrepaired. In addition to activating DNA repair pathways, the response to radiation also involves the tumor microenvironment, cell death pathways, immune responses and different types of cell death and proliferation receptors. In recent years, personalized medicine, which tailors treatments to individual patients, has gained increasing attention in cancer care. The development of chemo- and radiosensitivity predictive assays has become a key focus of cancer research. Despite the potential impact of such assays on bladder cancer treatment, there is still no reliable test that can help clinicians and informs patients in choosing the best treatment. This review aims to highlight studies that attempted to characterize bladder cancer radiosensitivity and to discuss the potential biomarkers that could be used to develop bladder cancer radiosensitivity predictive assays.

[Bladder-sparing trimodal therapy for muscle invasive bladder cancer]

Organ-sparing strategies in the management of local or locally advanced cancers meet a dual objective: tumor control and preservation of the function of the involved organ. Given the morbidity and mortality of cystectomy and its impact on quality of life and bladder function, bladder-sparing strategies have emerged for the management of urothelial muscle invasive bladder cancer, mostly through trimodal treatment, which consists in maximal trans-urethral resection of bladder tumor, followed by chemo-radiotherapy. This review presents the modalities of trimodal treatment, before exposing the advantages and limitations of this strategy compared to cystectomy among operable patients. Despite the absence of comparative data from randomized trials, the two approaches seem to provide similar oncological results among appropriately selected patients. In modern series, the rate of salvage cystectomy is approximately 15% at 5 years; this delayed cystectomy does not seem to be associated with greater morbidity and mortality as compared to upfront cystectomy. Emphasis is placed in the review on quality of life data of these two approaches. In order to optimize the selection of patients eligible to trimodal therapy, the classical predictive factors of response to radio(chemo)therapy are critically analyzed, with the perspective of innovative molecular biomarkers. Finally, a close multidisciplinary collaboration is needed for the choice and the execution of the therapeutic strategy, and the patient should be fully involved in the decision-making process.