Prevalence of Histopathological Variants of Prostate Cancer in Needle Biopsy Specimens: A Systematic Review and Meta-Analysis

Background: Prostate cancer is one of the most common malignancies affecting men worldwide and represents a significant cause of cancer-related morbidity and mortality. Histopathological evaluation of prostate needle biopsy specimens remains the gold standard for diagnosis and provides essential information regarding tumor type, grade, and biological behavior. Although conventional acinar adenocarcinoma constitutes the majority of cases, several histological variants with distinct clinical implications have been reported.

Objective: To determine the pooled prevalence of histopathological variants of prostate cancer diagnosed in needle biopsy specimens through a systematic review and meta-analysis.

Methods: A systematic literature search was conducted in PubMed, Scopus, Web of Science, and Google Scholar for studies published between 2000 and 2025 that reported histopathological variants of prostate cancer diagnosed by needle biopsy. Studies reporting the frequency of histological subtypes were included. Data extraction and quality assessment were performed independently by two reviewers. Pooled prevalence estimates were calculated using a random-effects model.

Results: A total of 32 studies comprising 8,764 patients met the inclusion criteria. The pooled prevalence of conventional acinar adenocarcinoma was 91.4%. Among variant histologies, ductal adenocarcinoma accounted for 3.2%, mucinous adenocarcinoma for 1.8%, small cell carcinoma for 1.1%, and signet-ring cell carcinoma for 0.6%.

Conclusion: Conventional acinar adenocarcinoma remains the predominant histopathological subtype of prostate cancer in needle biopsy specimens. Rare histological variants occur infrequently but carry important prognostic and therapeutic implications.