BackgroundThe landscape of prostate cancer (PCa) segmentation within multiparametric magnetic resonance imaging (MP‐MRI) was fragmented, with a noticeable lack of consensus on incorporating background details, culminating in inconsistent segmentation outputs. Given the complex and heterogeneous nature of PCa, conventional imaging segmentation algorithms frequently fell short, prompting the need for specialized research and refinement.PurposeThis study sought to dissect and compare various segmentation methods, emphasizing the role of background information and gland masks in achieving superior PCa segmentation. The goal was to systematically refine segmentation networks to ascertain the most efficacious approach.MethodsA cohort of 232 patients (ages 61–73 years old, prostate‐specific antigen: 3.4–45.6 ng/mL), who had undergone MP‐MRI followed by prostate biopsies, was analyzed. An advanced segmentation model, namely Attention‐Unet, which combines U‐Net with attention gates, was employed for training and validation. The model was further enhanced through a multiscale module and a composite loss function, culminating in the development of Matt‐Unet. Performance metrics included Dice Similarity Coefficient (DSC) and accuracy (ACC).ResultsThe Matt‐Unet model, which integrated background information and gland masks, outperformed the baseline U‐Net model using raw images, yielding significant gains (DSC: 0.7215 vs. 0.6592; ACC: 0.8899 vs. 0.8601, p < 0.001).ConclusionA targeted and practical PCa segmentation method was designed, which could significantly improve PCa segmentation on MP‐MRI by combining background information and gland masks. The Matt‐Unet model showcased promising capabilities for effectively delineating PCa, enhancing the precision of MP‐MRI analysis.