Diffusion-weighted magnetic resonance imaging in management of bladder cancer, particularly with multimodal bladder-sparing strategy

Abstract

Bladder-sparing strategy for muscle-invasive bladder cancer (MIBC) is increasingly demanded instead of radical cystectomy plus urinary diversion. Multimodal therapeutic approaches consisting of transurethral resection, chemotherapy, radiotherapy and/or partial cystectomy improve patients’ quality of life by preserving their native bladder and sexual function without compromising oncological outcomes. Because a favorable response to chemoradiotherapy (CRT) is a prerequisite for successful bladder preservation, predicting and monitoring therapeutic response is an essential part of this approach. Diffusion-weighted magnetic resonance imaging (DW-MRI) is a functional imaging technique increasingly applied to various types of cancers. Contrast in this imaging technique derives from differences in the motion of water molecules among tissues and this information is useful in assessing the biological behavior of cancers. Promising results in predicting and monitoring the response to CRT have been reported in several types of cancers. Recently, growing evidence has emerged showing that DW-MRI can serve as an imaging biomarker in the management of bladder cancer. The qualitative analysis of DW-MRI can be applied to detecting cancerous lesion and monitoring the response to CRT. Furthermore, the potential role of quantitative analysis by evaluating apparent diffusion coefficient values has been shown in characterizing bladder cancer for biological aggressiveness and sensitivity to CRT. DW-MRI is a potentially useful tool for the management of bladder cancer, particularly in multimodal bladder-sparing approaches for MIBC.

Keywords: Diffusion magnetic resonance imaging, Bladder cancer, Urothelial carcinoma, Chemotherapy, Radiotherapy

Core tip: Diffusion-weighted magnetic resonance imaging (DW-MRI) is a functional imaging increasingly applied in the management of bladder cancer. This imaging offers unique information reflecting physiological character of the tissues by quantifying the diffusion of water molecules. DW-MRI provides accurate information for the diagnosis of bladder cancer in a noninvasive manner. Furthermore, growing evidence has emerged showing that DW-MRI can serve as an imaging biomarker of bladder cancer for assessing biologic aggressiveness and therapeutic sensitivity and for monitoring the therapeutic response. This review focuses on the potential role of DW-MRI in multimodal organ-preservation strategies for bladder cancer.