title: Sex-Specific Differences in Colon Cancer when Quality Measures Are Adhered to: Results from International, Prospective, Multicenter Clinical Trials.
abstract: BACKGROUND
  There is no consensus on the relationship between patient sex and the location, stage, and oncologic outcome of colon cancer (CC). We hypothesized that there is a sex-specific difference in the biology and management of CC.
  
  
  METHODS
  Our cohort was drawn from a database of patients enrolled in international trials of nodal ultrastaging for nonmetastatic CC. These trials required strict adherence to surgical and pathologic quality measures. Postoperative follow-up included colonoscopy at 1 and 4 years and annual CT scans. Sex-specific differences in tumor biology, location, stage, and recurrence were evaluated by chi-square, Fischer's exact, and independent t-tests.
  
  
  RESULTS
  The cohort included 435 males (median age 69 years) and 423 females (median age 70 years). Females had more right-sided (p = 0.03) and earlier T stage (p = 0.05) tumors, but there was no sex-based difference in pathologic grade, total lymph nodes retrieved, nodal positivity (p = 0.47) or lymphovascular invasion (p = 0.45). The overall 4-year disease-free survival (DFS) was comparable in females and males (77.9% and 77.5%, respectively). By multivariate analysis, only nodal positivity and cancer recurrence affected overall survival (OS) (p = 0.008). Neither sex nor primary tumor affected DFS or OS.
  
  
  CONCLUSIONS
  This is the first prospective study to demonstrate sex-specific differences in location and T stage of CC when surgical and pathologic management adhered to strict quality standards. The predominance of right-sided CC in females suggests that flexible sigmoidoscopy may be inadequate for screening and surveillance. Interestingly, earlier stage and right-sided location did not confer a DFS or OS advantage for women. Additional studies are needed to determine why females have a higher propensity for right-sided lesions and a potential difference in CC biology.
authors.affiliation: Department of Surgical Oncology, John Wayne Cancer Institute, University of California Los Angeles, Santa Monica, CA Department of Medicine, University of California Los Angeles, Santa Monica, CA Department of Surgery, University of California Los Angeles, Santa Monica, CA Department of Surgery, Chaim Sheba Medical Center, Tel Hashomer, Israel Department of Surgical Oncology, Faculty of Medicine, University of Novi Sad, Novi Sad, Serbia Department of Surgery, Uniformed Services University of the Health Sciences, Bethesda, MD.
authors.forename: Shrawan G
authors.initials: SG
authors.lastname: Gaitonde
authors.forename: Aviram
authors.initials: A
authors.lastname: Nissan
authors.forename: Mladjan
authors.initials: M
authors.lastname: Protić
authors.forename: Alexander
authors.initials: A
authors.lastname: Stojadinovic
authors.forename: Zev A
authors.initials: ZA
authors.lastname: Wainberg
authors.forename: David C
authors.initials: DC
authors.lastname: Chen
authors.forename: Anton J
authors.initials: AJ
authors.lastname: Bilchik
mesh_terms: D000368:Aged; D003110:Colonic Neoplasms / Q000453:epidemiology / Q000473:pathology* / Q000601:surgery*; D003113:Colonoscopy; D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis / Q000473:pathology*; D008297:Male; D009364:Neoplasm Recurrence, Local; D009367:Neoplasm Staging; D011446:Prospective Studies; D011785:Quality Assurance, Health Care; D012737:Sex Factors; D015996:Survival Rate; D014057:Tomography, X-Ray Computed