title: Rectal cancer in hereditary nonpolyposis colorectal cancer.
abstract: BACKGROUND
  Hereditary nonpolyposis colorectal cancer (HNPCC) accounts for approximately 2% to 5% of all colorectal cancers. Rectal cancer in HNPCC is not well characterized.
  
  
  METHODS
  A retrospective medical record review of HNPCC patients with colorectal cancer diagnosis from December 1948 to December 1999 was performed in an attempt to elucidate the natural history of rectal cancer in HNPCC. Group A consisted of patients diagnosed with rectal cancer as the index colorectal cancer. Group B consisted of patients diagnosed with rectal cancer as a metachronous colorectal cancer.
  
  
  RESULTS
  Twenty-five of 104 patients developed rectal cancer in our HNPCC registry. There were 18 patients in group A with a median age at diagnosis of rectal cancer of 48 years (range 24 to 79) and 7 patients in group B diagnosed at a median age of 58 years (range 45 to 68). Three of 18 patients (17%) in group A developed metachronous colon cancers at a median of 203 months (range 27 to 373) from the index rectal cancer. Rectal cancer in group B was diagnosed at a median 245 months (range 51 to 564) from the index colorectal cancer diagnosis.
  
  
  CONCLUSIONS
  Rectal cancer in HNPCC is not uncommon. The presentation of rectal carcinoma should not obviate the evaluation for HNPCC in suspected cases.
authors.affiliation: Department of Surgery, Roswell Park Cancer Institute and State University of New York at Buffalo, Elm and Carlton Streets, Buffalo, New York 14263, USA.
authors.forename: J S
authors.initials: JS
authors.lastname: Lee
authors.forename: N J
authors.initials: NJ
authors.lastname: Petrelli
authors.forename: M A
authors.initials: MA
authors.lastname: Rodriguez-Bigas
mesh_terms: D000230:Adenocarcinoma / Q000453:epidemiology*; D000328:Adult; D000368:Aged; D003123:Colorectal Neoplasms, Hereditary Nonpolyposis / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016609:Neoplasms, Second Primary / Q000453:epidemiology*; D012004:Rectal Neoplasms / Q000453:epidemiology*; D012042:Registries; D012189:Retrospective Studies; D012307:Risk Factors