Molecular Subtyping of Muscle-Invasive Bladder Cancer Predicts Benefit of Hypoxia-Targeting Therapy

Pushing the Envelope: The Role of Radiation Therapy in Non-muscle-Invasive Bladder Cancer

The standard of care for non-muscle-invasive bladder cancer (NMIBC) is transurethral resection followed by risk stratified use of intravesical immune- or chemotherapy and for multifocal, recurrent and high grade disease, radical cystectomy with high rates of cure. Bladder preservation analogous to the trimodality therapy approach in muscle-invasive bladder cancer (MIBC) has not been adequately explored but the available data suggests that NMIBC is a radioresponsive malignancy and that in a proportion of patients bladder preservation would be possible. Combination modality with chemotherapy, hypoxia sensitisation, hyperthermia and immunotherapy are all approaches which have been shown effective. Unfortunately the quality of the available data is poor. Although there are many putative prognostic biomarkers for progression in NMIBC none have emerged in clinical use and there are none predictive for response to non-surgical treatment. This would be an important component of future large scale studies to evaluate the precise role of radiotherapy within a multimodality schedule for bladder reservation in NMIBC.

Current State of Personalized Genitourinary Cancer Radiotherapy in the Era of Precision Medicine

Radiation therapy plays a crucial role for the management of genitourinary malignancies, with technological advancements that have led to improvements in outcomes and decrease in treatment toxicities. However, better risk-stratification and identification of patients for appropriate treatments is necessary. Recent advancements in imaging and novel genomic techniques can provide additional individualized tumor and patient information to further inform and guide treatment decisions for genitourinary cancer patients. In addition, the development and use of targeted molecular therapies based on tumor biology can result in individualized treatment recommendations. In this review, we discuss the advances in precision oncology techniques along with current applications for personalized genitourinary cancer management. We also highlight the opportunities and challenges when applying precision medicine principles to the field of radiation oncology. The identification, development and validation of biomarkers has the potential to personalize radiation therapy for genitourinary malignancies so that we may improve treatment outcomes, decrease radiation-specific toxicities, and lead to better long-term quality of life for GU cancer survivors.

Will the Use of Biomarkers Improve Bladder Cancer Radiotherapy Delivery?

Advances in the field of cancer biology and molecular techniques have led to a better understanding of the molecular underpinnings driving cancer development and outcomes. Simultaneously, advances in imaging have allowed for improved sensitivity in initial staging, radiotherapy planning and follow-up of numerous cancers. These two phenomena have led to the development of biomarkers that can guide therapy in multiple malignancies. In bladder cancer, there is extensive ongoing research into the identification of biomarkers that can help tailor personalised approaches for treatment based on the intrinsic tumour biology. However, the delivery of bladder cancer radiotherapy as part of trimodality therapy currently has a paucity of biomarkers to guide treatment. Here we summarise the existing literature and ongoing investigations into potential predictive and prognostic molecular and imaging biomarkers that may one day guide selection for utilisation of radiotherapy as part of trimodality therapy, guide selection of the radiosensitising agent, guide radiation dose and target, and guide surveillance for recurrence after trimodality therapy.