Prostate cancer invading the rectum: a clinicopathological study of 18 cases

SummaryAimsProstate cancer may involve the rectum and cause severe perineal pain. The aim of this study was to understand the rectal involvement by prostate cancer and its clinical significance.MethodsWe evaluated pathological and clinical features of 18 cases of prostate cancer with rectal involvement.ResultsAll patients presented with intractable perineal pain. Twelve patients received rectal biopsies, which revealed poorly differentiated prostatic adenocarcinoma (n = 6), squamous cell carcinoma (n = 3), angiosarcoma (n = 1), or no tumour (n = 2). All patients received palliative total pelvic exenteration, which demonstrated prostate cancer invading the rectal wall. In these resection specimens, the tumour consisted of poorly differentiated prostatic adenocarcinoma (n = 16), squamous cell carcinoma (n = 1), or angiosarcoma (n = 1). In addition, six cases of prostatic adenocarcinomas also showed focal squamous (n = 3) or high-grade neuroendocrine (n = 3) differentiation. Nine patients died at a mean time of 18 months (range, 2–69 months) after surgery. The remaining nine patients were alive with a mean follow-up time of 15 months (range, 3–34 months), but four patients developed distant metastases.ConclusionProstate cancer with rectal involvement often develops heterogeneous differentiation and carries a dismal prognosis.