Brief Article
Copyright ©2013 Baishideng Publishing Group Co., Limited. All rights reserved.
World J Gastroenterol. Jun 7, 2013; 19(21): 3241-3248
Published online Jun 7, 2013. doi: 10.3748/wjg.v19.i21.3241
Survival after inflammatory bowel disease-associated colorectal cancer in the Colon Cancer Family Registry
Scott V Adams, Dennis J Ahnen, John A Baron, Peter T Campbell, Steven Gallinger, William M Grady, Loic LeMarchand, Noralane M Lindor, John D Potter, Polly A Newcomb
Scott V Adams, William M Grady, John D Potter, Polly A Newcomb, Cancer Prevention, Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, United States
Dennis J Ahnen, Department of Medicine, Denver VA Medical Center and University of Colorado School of Medicine, Denver, CO 80045, United States
John A Baron, Department of Medicine, University of North Carolina, Chapel Hill, NC 27599, United States
Peter T Campbell, Epidemiology Research Program, Department of Intramural Research, American Cancer Society, Atlanta, GA 30303, United States
Steven Gallinger, Division of General Surgery, University of Toronto, Toronto, ON M5G2C4, Canada
Loic LeMarchand, Cancer Research Center of Hawaii, University of Hawaii, Honolulu, HI 96813, United States
Noralane M Lindor, Department of Health Science Research, Mayo Clinic Arizona, Scottsdale, AZ 85259, United States
Author contributions: Adams SV conceived, designed and performed the analysis, and drafted the manuscript; Ahnen DJ, Baron JA, Campbell PT, Gallinger S, Grady WM, LeMarchand L, Lindor NM, Potter JD and Newcomb PA contributed data and reviewed the results and manuscript.
Supported by The American Society of Preventive Oncology/Prevent Cancer Foundation/American Society for Clinical Oncology Cancer Prevention Research Fellowship to SVA; the Australasian Colorectal Cancer Family Registry, No. U01 CA097735; the Familial Colorectal Neoplasia Collaborative Group, No. U01 CA074799; the Mayo Clinic Cooperative Family Registry for Colon Cancer Studies, No. U01 CA074800; the Ontario Registry for Studies of Familial Colorectal Cancer, No. U01 CA074783; the Seattle Colorectal Cancer Family Registry, No. U01 CA074794; the University of Hawaii Colorectal Cancer Family Registry, No. U01 CA074806; and the University of California, Irvine Informatics Center, No. U01 CA078296
Correspondence to: Scott V Adams, PhD, Cancer Prevention, Public Health Sciences, Fred Hutchinson Cancer Research Center, M3-B232, PO Box 19024, Seattle, WA 98109, United States.
Telephone: +1-206-6676427 Fax: +1-206-6675977
Received: December 13, 2012
Revised: March 12, 2013
Accepted: April 3, 2013
Published online: June 7, 2013

AIM: To investigate the survival of individuals with colorectal cancer (CRC) with inflammatory bowel disease (IBD-associated CRC) compared to that of individuals without IBD diagnosed with CRC.

METHODS: Epidemiologic, clinical, and follow-up data were obtained from the Colon Cancer Family Registry (Colon CFR). IBD-associated cases were identified from self-report of physician diagnosis. For a subset of participants, medical records were examined to confirm self-report of IBD. Cox proportional hazards regression was applied to estimate adjusted hazard ratios (aHR) and 95%CI of mortality, comparing IBD-associated to non-IBD-associated CRC, adjusted for age at CRC diagnosis, sex, Colon CFR phase, and number of prior endoscopies. Following imputation to complete CRC stage information, adjustment for CRC stage was examined.

RESULTS: A total of 7202 CRC cases, including 250 cases of IBD-associated CRC, were analyzed. Over a twelve year follow-up period following CRC diagnosis, 2013 and 74 deaths occurred among non-IBD associated CRC and IBD-associated CRC patients, respectively. The difference in survival between IBD-associated and non-IBD CRC cases was not statistically significant (aHR = 1.08; 95%CI: 0.85-1.36). However, the assumption of proportional hazards necessary for valid inference from Cox regression was not met over the entire follow-up period, and we therefore limited analyses to within five years after CRC diagnosis when the assumption of proportional hazards was met. Over this period, there was evidence of worse prognosis for IBD-associated CRC (aHR = 1.36; 95%CI: 1.05-1.76). Results were similar when adjusted for CRC stage, or restricted to IBD confirmed in medical records.

CONCLUSION: These results support the hypothesis that IBD-associated CRC has a worse prognosis than non-IBD-associated CRC.

Keywords: Colorectal cancer, Inflammatory bowel disease, Outcomes research, Cancer survival, Inflammation

Core tip: Inflammatory bowel disease (IBD) - and more generally, inflammation - increases risk of colorectal cancer (CRC). Inflammation may also promote cancer progression and metastasis, and therefore, inflammation might be associated with shorter survival with CRC. This study examined whether CRC that occurs in patients with IBD has a worse prognosis than CRC in patients without IBD.