title: 5-fluorouracil-induced small bowel toxicity in patients with colorectal carcinoma.
abstract: BACKGROUND
  Diarrhea and oral mucositis are the most frequently reported gastrointestinal side effects caused by 5-fluorouracil (5-FU). Diarrhea may be severe in 10-30% of patients and is schedule-dependent. 5-FU-induced gastrointestinal toxicity predominantly affects the upper and the lower gastrointestinal tract. The current study describes 5-FU-induced small bowel toxicity as an entity that to the authors' knowledge has not been reported previously in patients with colon carcinoma receiving 5-FU-based therapy.
  
  
  METHODS
  The authors report a series of six patients with colorectal carcinoma who developed acute small bowel toxicity after treatment with 5-FU and leucovorin.
  
  
  RESULTS
  Six patients developed a clinical picture of acute abdominal pain and diarrhea. Small bowel damage was documented by laparotomy in two patients, by colonoscopy in one patient, and by abdominal computed tomography scan in three patients. The course was complicated by recurrence of symptoms in one patient who was rechallenged with 5-FU and leucovorin, but the remaining four patients were rechallenged safely with lower doses of 5-FU and leucovorin after the acute toxicity episode. A possible explanation for this toxicity is 5-FU-induced vasospasm and/or decrease in fibrinolytic activity that results in decreased mucosal blood flow.
  
  
  CONCLUSIONS
  5-FU-induced small bowel toxicity is a potentially severe toxicity that may occur in patients with colon carcinoma or other malignancies who are receiving 5-FU-based therapy. [See editorial on pages 1099-100, this issue.]
authors.affiliation: Gastrointestinal Oncology Service, Department of Medicine, Memorial Sloan-Kettering Cancer Center and the Cornell University Medical College, New York, New York 10021, USA.
authors.forename: F
authors.initials: F
authors.lastname: Fata
authors.forename: I G
authors.initials: IG
authors.lastname: Ron
authors.forename: N
authors.initials: N
authors.lastname: Kemeny
authors.forename: E
authors.initials: E
authors.lastname: O'Reilly
authors.forename: D
authors.initials: D
authors.lastname: Klimstra
authors.forename: D P
authors.initials: DP
authors.lastname: Kelsen
mesh_terms: D000230:Adenocarcinoma / Q000188:drug therapy*; D000328:Adult; D000368:Aged; D000964:Antimetabolites, Antineoplastic / Q000008:administration & dosage / Q000633:toxicity*; D015179:Colorectal Neoplasms / Q000188:drug therapy*; D003967:Diarrhea / Q000139:chemically induced; D005260:Female; D005472:Fluorouracil / Q000008:administration & dosage / Q000633:toxicity*; D006801:Humans; D007413:Intestinal Mucosa / Q000187:drug effects / Q000473:pathology; D007421:Intestine, Small / Q000187:drug effects*; D002955:Leucovorin / Q000008:administration & dosage; D008297:Male; D008875:Middle Aged
chemical_list: D000964:Antimetabolites, Antineoplastic; D002955:Leucovorin; D005472:Fluorouracil