Prostate cancer is the second-most lethal cancer in men. Since early diagnosis and treatment can drastically increase the 5-year survival rate of patients to >99%, magnetic resonance imaging (MRI) has been utilized due to its high sensitivity of 88%. However, due to lack of access to MRI, transrectal b-mode ultrasound (TRUS)-guided systematic prostate biopsy remains the standard of care for 93% of patients. While ubiquitous, TRUS-guided prostate biopsy suffers from the lack of lesion targeting, resulting in a sensitivity of 48%. To address this gap, we perform a preliminary study to assess the feasibility of localizing clinically significant cancer on b-mode ultrasound images of the prostate as input and propose a deep learning framework that learns to distinguish cancer at the pixel level. The proposed deep learning framework consists of a convolutional network with deep supervision at various scales and a clinical decision module that simultaneously learns to reduce false positive lesion predictions. We evaluated our deep learning framework using b-mode TRUS data with pathology confirmation from 330 patients, including 123 patients with pathology-confirmed cancer. Our results demonstrate the feasibility of using b-mode ultrasound images to localize prostate cancer lesions with a patient-level sensitivity and specificity of 68% and 91% respectively, compared to the reported clinical standard of 48% and 99%. The outcomes of this study show the promise of using a deep learning framework to localize prostate cancer lesions on the universally available b-mode ultrasound images; eventually improving the prostate biopsy procedures and enhancing the clinical outcomes for prostate cancer patients.
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