title: US intergroup anal carcinoma trial: tumor diameter predicts for colostomy.
abstract: OBJECTIVE
  The US Gastrointestinal Intergroup Radiation Therapy Oncology Group 98-11 anal carcinoma trial showed that cisplatin-based concurrent chemoradiotherapy resulted in a significantly higher rate of colostomy compared with mitomycin-based therapy. Established prognostic variables for patients with anal carcinoma include tumor diameter, clinical nodal status, and sex, but pretreatment variables that would predict the likelihood of colostomy are unknown.
  
  
  METHODS
  A secondary analysis was performed by combining patients in the two treatment arms to evaluate whether new predictive and prognostic variables would emerge. Univariate and multivariate analyses were carried out to correlate overall survival (OS), disease-free survival, and time to colostomy (TTC) with pretreatment and treatment variables.
  
  
  RESULTS
  Of 682 patients enrolled, 644 patients were assessable and analyzed. In the multivariate analysis, tumor-related prognosticators for poorer OS included node-positive cancer (P < or = .0001), large (> 5 cm) tumor diameter (P = .01), and male sex (P = .016). In the treatment-related categories, cisplatin-based therapy was statistically significantly associated with a higher rate of colostomy (P = .03) than was mitomycin-based therapy. In the pretreatment variables category, only large tumor diameter independently predicted for TTC (P = .008). Similarly, the cumulative 5-year colostomy rate was statistically significantly higher for large tumor diameter than for small tumor diameter (Gray's test; P = .0074). Clinical nodal status and sex were not predictive of TTC.
  
  
  CONCLUSIONS
  The combined analysis of the two arms of RTOG 98-11, representing the largest prospective database, reveals that tumor diameter (irrespective of the nodal status) is the only independent pretreatment variable that predicts TTC and 5-year colostomy rate in patients with anal carcinoma.
authors.affiliation: Department of Gastrointestinal Medical Oncology, The University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Blvd, Mail Stop 426, Houston, TX 77030-4009, USA. jajani@mdanderson.org
authors.forename: Jaffer A
authors.initials: JA
authors.lastname: Ajani
authors.forename: Kathryn A
authors.initials: KA
authors.lastname: Winter
authors.forename: Leonard L
authors.initials: LL
authors.lastname: Gunderson
authors.forename: John
authors.initials: J
authors.lastname: Pedersen
authors.forename: Al B
authors.initials: AB
authors.lastname: Benson
authors.forename: Charles R
authors.initials: CR
authors.lastname: Thomas
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Mayer
authors.forename: Michael G
authors.initials: MG
authors.lastname: Haddock
authors.forename: Tyvin A
authors.initials: TA
authors.lastname: Rich
authors.forename: Christopher G
authors.initials: CG
authors.lastname: Willett
mesh_terms: D000328:Adult; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D001005:Anus Neoplasms / Q000473:pathology* / Q000601:surgery / Q000628:therapy; D002945:Cisplatin / Q000008:administration & dosage; D003125:Colostomy; D003131:Combined Modality Therapy; D005260:Female; D005472:Fluorouracil / Q000008:administration & dosage; D006801:Humans; D008297:Male; D016685:Mitomycin / Q000008:administration & dosage; D015999:Multivariate Analysis; D011379:Prognosis; D016016:Proportional Hazards Models; D016032:Randomized Controlled Trials as Topic; D016019:Survival Analysis; D013997:Time Factors
chemical_list: D016685:Mitomycin; D002945:Cisplatin; D005472:Fluorouracil