Location of Prostate Cancers Determined by Multiparametric and MRI-Guided Biopsy in Patients With Elevated Prostate-Specific Antigen Level and at Least One Negative Transrectal Ultrasound-Guided Biopsy

Abstract

Objective: The purpose of this article is to identify histopathologically proven prostate cancer locations using MRI followed by MRI-guided biopsy in patients with elevated prostate-specific antigen (PSA) levels and at least one negative transrectal ultrasound (TRUS)-guided biopsy session. Our hypothesis is that in this patient group most cancers are located in the anterior portion of the prostate. This may have implications for the biopsy strategy regarding the location of sampling.

Materials and methods: This retrospective study consisted of 872 consecutive men who had undergone MRI-guided prostate biopsy. Inclusion criteria were PSA level greater than or equal to 4 ng/mL, one or more negative TRUS-guided biopsy session, the presence of suspicious lesions on previous multiparametric MRI, and prostate cancer histopathologically proven by MRI-guided biopsy. Thereafter, the location of intermediate- or high-risk cancers and cancers with a maximum cancer core length of 6 mm or longer were determined. The proportion of cancer locations was compared using a chi-square test. One-way ANOVA analyses were performed to compare patient characteristics.

Results: Results were presented on both a patient and lesion basis because a single patient can have multiple lesions. In total, 176 of 872 patients met the inclusion criteria. Prostate cancer was detected in 202 of 277 (73%) suspicious lesions. In total, 76% of patients had cancer of the transition zone and anterior fibromuscular stroma. Peripheral zone cancers were found in 30% of the patients, and 6% had cancers in both zones. In 70% of cases (141/202; 95%, CI, 63-76%), lesions were located anteriorly; this included 75% (132/176; 95%, CI, 69-81%) of patients. Intermediate- or high-risk prostate cancer was found in 93% (128/138; 95%, CI, 88-96%) of patients. Of these patients, 73% (94/128; 95%, CI, 66-81%) had anterior involvement. Cancers with a maximum cancer core length of 6 mm or more were more likely to be located in the anterior part of the prostate than were cancers with a core length of less than 6 mm (66% vs 6%). Most cancers 58% (102/176; 95% CI, 51-65%) were found in the mid prostate. Anterior involvement of prostate cancer detected by MRI-guided biopsy was statistically significantly (p = 0.04) higher in patients with two or more negative TRUS-guided biopsy sessions (79%) than in those with one negative TRUS-guided biopsy session (55%).

Conclusion: Anterior involvement was high (76%) in patients with an elevated PSA level and one or more negative TRUS-guided biopsy session, and the majority of these cancers (93%) were intermediate or high risk.

Keywords: MRI-guided biopsy; location; prostate cancer.