Does a large prostate size, small lesion volume, or long needle distance from the probe to the lesion reduce magnetic resonance imaging–targeted cancer detection?

Background We aimed to evaluate whether large prostate size, small lesion volume, or long lesion distance from the ultrasound probe tip would decrease cancer detection in transrectal magnetic resonance imaging (MRI)–targeted biopsies. Materials and methods Patients who underwent MRI-targeted biopsy at our institution between May 2017 and August 2019 were enrolled in a prospective database. Three to 5 cores were obtained from ≥2 PI-RADS (prostate imaging reporting and data system) v2 lesions. A multivariable model was created that included needle distance to the lesion, prostate specific antigen, PI-RADS, lesion volume, and prostate volume. Results A total of 377 patients with 533 lesions underwent a biopsy during the study period. A total of 233 (44%) lesions were positive for prostate cancer, and 173 (32%) lesions had clinically significant prostate cancer. The mean needle distance to the lesion was 11.7 mm (interquartile range, 7.6–15.5 mm). The likelihood of obtaining a positive core on biopsy decreased as the distance from the ultrasound probe increased for all prostate cancers and clinically significant prostate cancer (p = 0.018 and p = 0.004, respectively). Every 10 mm from the rectum, there was an 8%–10% decrease in the rate of cancer detection. Similarly, as the prostate volume increased, the odds of obtaining a positive core also decreased (p = .039). There was no significant association between the lesion size and amount of cancer obtained on biopsy. Conclusions Our data showed that transrectal MRI-targeted biopsy cancer detection modestly decreased the further the lesion was from the ultrasound probe and with a large prostate volume but could not prove that lesion volume was a significant predictor of the amount of cancer detected.