Influence of social deprivation and remoteness on the likelihood of sphincter amputation for rectal cancer: a high-resolution population-based study

Background: Medical care in rectal cancer is subject to social inequality. According to the last French guidelines, a 1-cm distal margin below the lower pole of the rectal tumor is now considered sufficient. This extends the limits of the current sphincter preservation gold standard. Like for other innovative technics, the dissemination of such technics is often subject to social and geographical inequalities. The objective was to analyze whether sphincter preservation in rectal cancer is subject to social or geographical inequality.

Methods: The odds of sphincter preservation was modeled by logistic regression among the 1453 patients in the Calvados digestive cancer registry between 1 January 1997 and 31 December 2015 by examining some of the variables that could influence it: social inequalities and geographical remoteness, sex, age, and stage.

Results: A total of 69.4% of the population received sphincter preservation. Patients in the more deprived quintiles had a significantly higher probability of having sphincter amputation (odds ratio (OR) = 1.469 (1.046-2.064)). This result was no longer significant after adjustment on stage and travel time. There was a dose-effect pattern of geographical remoteness on likelihood of sphincter preservation with a progressive increase in OR between patients living the nearest and the furthest from the reference center (p-trend = 0.0178).

Conclusion: This study shows that the probability of receiving sphincter preservation is influenced by the social environment and strongly influenced by remoteness. Although management guidelines have had a huge impact on the rates of sphincter preservation, they have not reduced the influence of the social and geographical environment on sphincter preservation.