title: Prostate cancer invading the rectum: a clinicopathological study of 18 cases.
abstract: OBJECTIVE
  Prostate 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.
  
  
  METHODS
  We evaluated pathological and clinical features of 18 cases of prostate cancer with rectal involvement.
  
  
  RESULTS
  All 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.
  
  
  CONCLUSIONS
  Prostate cancer with rectal involvement often develops heterogeneous differentiation and carries a dismal prognosis.
authors.affiliation: Department of Pathology, The University of Texas M D Anderson Cancer Center, Houston, TX 77030-4009, USA. ccguo@mdanderson.org
authors.forename: Charles C
authors.initials: CC
authors.lastname: Guo
authors.forename: Louis L
authors.initials: LL
authors.lastname: Pisters
authors.forename: Patricia
authors.initials: P
authors.lastname: Troncoso
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology* / Q000628:therapy; D000368:Aged; D001706:Biopsy; D002294:Carcinoma, Squamous Cell / Q000473:pathology* / Q000628:therapy; D003131:Combined Modality Therapy; D017809:Fatal Outcome; D006394:Hemangiosarcoma / Q000473:pathology* / Q000628:therapy; D006801:Humans; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D011379:Prognosis; D011471:Prostatic Neoplasms / Q000473:pathology* / Q000628:therapy; D012004:Rectal Neoplasms / Q000473:pathology*