Assessing tumor hypoxia in prostate cancer using intravoxel incoherent motion: a hypothesis-generating study.

AIM: Hypoxia plays a key role in tumor aggressiveness and progression in prostate cancer (PCa). However, current methods for detecting tumor hypoxia in PCa are either invasive or suboptimal. This study investigates the use of Intravoxel Incoherent Motion (IVIM) in Magnetic Resonance Imaging (MRI) as a noninvasive approach to detect tumor hypoxia in PCa.

MATERIALS AND

METHODS

This retrospective study included 67 consecutive patients diagnosed with PCa or suspicious lesions (Prostate Imaging Reporting and Data System [PI-RADS] scores 3, 4, 5) on multiparametric MRI between November 2019 and February 2021. IVIM images were analyzed, and tumor and normal peripheral zones were segmented separately using 3D slicer software (version 4.10.2). IVIM parameters, including diffusion coefficient (D), blood flow-related parameter (FD), pseudodiffusion coefficient (D∗), and perfusion fraction (f), were extracted using MATLAB. Tumor sections were stained with anti-HIF-1α antibody to determine hypoxia status. Pathological findings were compared with MRI data by an independent radiologist.

RESULTS

Of the 67 patients, 33 were HIF-1α negative, while 34 were positive. No significant differences were found in mean age, prostate-specific antigen (PSA), density of prostate-specific antigen (dPSA), or prostate volume between groups. However, hypoxia-positive lesions had significantly lower diffusion map values (p=0.02). Blood flow-related parameter (FD) values were also lower, with borderline significance (p=0.05). Hypoxia was more prevalent in International Society of Urological Pathology (ISUP) tumor grades 3-5 tumors (79.3% vs 54.6%, p=0.02) and was associated with worse National Comprehensive Cancer Network (NCCN) risk stratification (p=0.002).

CONCLUSIONS

Preliminary findings suggest IVIM may serve as a noninvasive biomarker for predicting tumor hypoxia and PCa aggressiveness. Further validation in prospective studies is needed.