Systematic Review Links the Prevalence of Intraductal Carcinoma of the Prostate to Prostate Cancer Risk Categories.

Unlabelled: Intraductal carcinoma of the prostate (IDC-P) is associated with poor prognosis. While it is often regarded as a rare pathology, the prevalence of IDC-P remains unclear, with variable reports from small and disparate patient populations. To determine how common IDC-P is across the spectrum of prostate cancer, we conducted a systematic review correlating IDC-P prevalence with prostate cancer risk. Electronic searches of the OVID Medline, PubMed, and Scopus literature databases identified 38 patient cohorts in 24 articles, which were divided between four prostate cancer risk categories (low, moderate, high, and recurrent or metastatic disease). This review, which included radical prostatectomy and prostate biopsy specimens from >7000 patients, revealed an unexpectedly high rate of IDC-P. The IDC-P prevalence increased from 2.1% in low-risk patient cohorts to 23.1%, 36.7%, and 56.0% in moderate-risk, high-risk, and metastatic or recurrent disease risk categories, respectively (p<0.0001). IDC-P was also highly prevalent in tumours following androgen deprivation therapy or chemotherapy (60%). Contrary to common perceptions, this study demonstrates a strong association between IDC-P prevalence and aggressive prostate cancer, with a significantly higher frequency in high-risk disease. Greater recognition and systematic reporting of IDC-P may improve patient risk stratification.

Patient Summary: Prostate cancer can grow within ducts of the prostate, as well as in prostate tissue. By reviewing all reports describing prostate cancer growing within ducts, we found that it occurs more commonly than many scientists and clinicians appreciate, especially in aggressive prostate cancers. We conclude that there should be more awareness of this pattern of prostate cancer.