Socioeconomic Position in Acute Colorectal Cancer Surgery

Overview

Acute colon cancer surgery has a poor 90-day mortality of 21.0% compared with only 3% after elective colorectal cancer surgery in Denmark. The high mortality after acute colon cancer surgery compared with elective surgery emphasizes the importance of identifying factors associated with acute onset and poor short-term survival after acute surgery. Socioeconomic position has previously showed to be a risk factor for acute versus elective onset of colorectal cancer. Furthermore, if patients with low socioeconomic position have higher postoperative mortality this could reflect differences in the treatment of patients according to their socioeconomic position. The aim of the clinical study is: 1. To examine if patients with short education, low income, living alone, or living in rural areas are more likely to undergo acute colorectal cancer surgery than elective surgery compared with patients with longer educations, higher income, living with a partner, or living in urban areas. 2. To examine if there is an association between education, income, cohabitation, or urbanicity and 1-year mortality after acute colorectal cancer surgery.

Hypothesis The investigators hypothesize that patients with short education, low income, living alone, or living in rural areas are, themselves or their physician, less likely to react to unspecified symptoms of colon cancer and have a higher risk of acute onset due to more progressed disease compared with patients with a higher socioeconomic position. Furthermore, the hypothesis is that there is an association between socioeconomic position and 90-day mortality after acute colorectal surgery, explained by patient, treatment or organizational related factors. Methods The study is a nationwide, historical cohort study with prospective collected data. All patients in Denmark will be followed up one year after surgery. Exposure is socioeconomic position measured by highest attained education, age and sex-adjusted income, cohabitation status, and urbanicity. Primary outcome in the first study is acute surgical procedure for colorectal cancer. Primary outcome in the second study is year mortality after acute colorectal cancer surgery or insertion of self-expanding metallic stent (SEMS). Analysis First study: Differences in socioeconomic position between patients undergoing acute and elective CRC surgery will be explored with a logistic regression model. We will include the following covariates in the analysis: Confounders: age, sex. Mediators: comorbidity (Charlson Comorbidity Index), BMI (Body Mass Index), alcohol, UICC-stage (The Union for International Cancer Control), smoking, tumor localization, income, education, cohabitation, urbanicity A sensitivity analysis will be conducted to examine if department volume adds to the effect of urbanicity. Second study: Differences in socioeconomic position in postoperative 1-year mortality after acute colorectal cancer surgery will be analysed with a cox regression model. We will include the following covariates in the analysis: Confounders: age, sex. Mediators: comorbidity (Charlson Comorbidity Index), BMI (Body Mass Index), alcohol, UICC-stage (The Union for International Cancer Control), smoking, tumor localization, income, education, cohabitation, urbanicity A sensitivity analysis will be conducted to examine if department volume adds to the effect of urbanicity. Ethical considerations The project has been approved by the Danish Data Protection Agency with journal no. 2015-41- 3726. Data will be handled according to Danish law and the Helsinki declaration. This study does not require written content from the participants, thus all data is retracted from databases and registries. In the presentation of final results all patients will remain anonymous and not identifiable according to Danish law. All data will be kept a minimum of 5 years.