Rural-urban differences in the long-term risk of colorectal cancer after adenoma removal: a population-based study.
BACKGROUND
We investigated the impact of municipality of residence on colonoscopic surveillance and colorectal cancer risk after adenoma resection in a French well-defined administrative area.


METHODS
This registry-based study included all patients residing in Côte d'Or (n=5769) first diagnosed with colorectal adenomas between January 1, 1990, and December 31, 1999. Information about colonoscopic surveillance and colorectal cancer incidence was collected until December 31, 2003.


RESULTS
A rural place of residence reduced the probability of colonoscopic surveillance in men [HR=0.89 (95%CI: 0.79-0.99), p=0.041] and in patients without family history of colorectal cancer [HR=0.91(0.82-0.99), p=0.044]. After a median follow-up of 7.7 years, 87 patients developed invasive colorectal cancer. After advanced adenoma removal, the standardized incidence ratio for colorectal cancer was 3.03 (95%CI: 1.92-4.54) for rural patients and 1.87 (95%CI: 1.26-2.66) for urban patients compared with the general population. The risk of colorectal cancer was higher in rural patients than in urban ones only after removal of the initial advanced adenoma [HR=1.73 (95%CI: 1.01-3.00, p=0.048)]. Further adjustment for surveillance colonoscopy, physician location, and other confounders had little impact on these results.


CONCLUSIONS
The increased risk of subsequent colorectal cancer after advanced adenoma removal in French rural patients was not explained by a lower rate of colonoscopic surveillance. The role of socio-economic and environmental factors requires further exploration.
CHRU Dijon, Centre d'investigation clinique, Dijon F-21000, France; INSERM CIC 1432, Dijon F-21000, France; INSERM U866 (Registre Bourguignon des Cancers Digestifs), Université de Bourgogne, Dijon, France.
Isabelle
I
Fournel
INSERM U866 (Registre Bourguignon des Cancers Digestifs), Université de Bourgogne, Dijon, France.
Vanessa
V
Cottet
CHRU Dijon, Centre d'investigation clinique, Dijon F-21000, France; INSERM CIC 1432, Dijon F-21000, France; INSERM U866 (Registre Bourguignon des Cancers Digestifs), Université de Bourgogne, Dijon, France.
Christine
C
Binquet
INSERM U866 (Registre Bourguignon des Cancers Digestifs), Université de Bourgogne, Dijon, France.
Valérie
V
Jooste
INSERM U866 (Registre Bourguignon des Cancers Digestifs), Université de Bourgogne, Dijon, France.
Jean
J
Faivre
CHRU Dijon, Centre d'investigation clinique, Dijon F-21000, France; INSERM CIC 1432, Dijon F-21000, France; INSERM U866 (Registre Bourguignon des Cancers Digestifs), Université de Bourgogne, Dijon, France.
Anne-Marie
AM
Bouvier
CHRU Dijon, Centre d'investigation clinique, Dijon F-21000, France; INSERM CIC 1432, Dijon F-21000, France; INSERM U866 (Registre Bourguignon des Cancers Digestifs), Université de Bourgogne, Dijon, France. Electronic address: bonithon@u-bourgogne.fr.
Claire
C
Bonithon-Kopp
D000236:Adenoma / Q000453:epidemiology* / Q000473:pathology / Q000601:surgery; D000368:Aged; D000369:Aged, 80 and over; D002277:Carcinoma / Q000175:diagnosis / Q000453:epidemiology*; D015331:Cohort Studies; D003113:Colonoscopy / Q000706:statistics & numerical data; D015179:Colorectal Neoplasms / Q000453:epidemiology* / Q000473:pathology / Q000601:surgery; D005260:Female; D005602:France / Q000453:epidemiology; D005843:Geography; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012306:Risk; D012424:Rural Population / Q000706:statistics & numerical data*; D014505:Urban Population / Q000706:statistics & numerical data*
Colonoscopic surveillance; Colorectal adenoma; Colorectal cancer; Geographical disparities