Intravesical BCG-induced granulomatous prostatitis mimicking prostate cancer in patients with non-muscle invasive bladder cancer: a systematic review

Purpose Bacillus Calmette–Guérin (BCG) therapy is a standard-of-care for non–muscle-invasive bladder cancer (NMIBC), and granulomatous prostatitis (GP) is a side effect often misdiagnosed as prostate cancer (PCa). We conducted a systematic review to clarify the clinical spectrum of BCG-induced GP. Methods MEDLINE, Embase, and Web of Science were searched in June 2026. We sought studies reporting GP associated with BCG therapy for NMIBC, including case reports and case series. Risk of bias was evaluated using ROBINS-I and JBI tools. Findings were synthesized narratively (CRD420261324758). Results Forty-seven studies were included, comprising 23 case reports, 19 case series, and 5 comparative studies. In case series, abnormal digital rectal examination findings were reported in 100/240 (42%) evaluable cases. PSA elevation (> 4 ng/mL) occurred in 104/194 (54%) patients but often declined spontaneously during follow-up. Suspicious MRI findings were common, with PI-RADS ≥ 4 lesions reported in 71/82 (87%) cases, whereas biopsy-confirmed PCa was detected only in 12/151 (7.9%) patients. However, Grade Group and definitions of clinically significant PCa (csPCa) were incompletely and inconsistently reported, precluding a reliable estimate of csPCa frequency. Limitations include the predominance of descriptive studies and potential selection bias. Conclusion BCG-induced GP frequently presents with transient PSA elevation and suspicious MRI findings that rarely indicate true PCa. In BCG-exposed patients with elevated PSA or PI-RADS ≥ 4 lesions, structured observation with careful follow-up should be considered before proceeding to immediate biopsy.