Association between education level and prognosis after esophageal cancer surgery : a Swedish population-based cohort study

Background: An association between education level and survival after esophageal cancer has recently been indicated, but remains uncertain. We conducted a large study with long follow-up to address this issue. Methods: This population-based cohort study included all patients operated for esophageal cancer in Sweden between 1987 and 2010 with follow-up until 2012. Level of education was categorized as compulsory (= 13 years). The main outcome measure was overall 5-year mortality after esophagectomy. Cox regression was used to estimate associations between education level and mortality, expressed as hazard ratios (HRs) with 95% confidence intervals (CIs), with adjustment for sex, age, co-morbidity, tumor stage, tumor histology, and assessing the impact of education level over time. Results: Compared to patients with high education, the adjusted HR for mortality was 1.29 (95% CI 1.07-1.57) in the intermediate educated group and 1.42 (95% CI 1.17-1.71) in the compulsory educated group. The largest differences were found in early tumor stages (T-stage 0-1), with HRs of 1.73 (95% CI 1.00-2.99) and 2.58 (95% CI 1.51-4.42) for intermediate and compulsory educated patients respectively; and for squamous cell carcinoma, with corresponding HRs of 1.38 (95% CI 1.07-1.79) and 1.52 (95% CI 1.19-1.95) respectively. Conclusions: This Swedish population-based study showed an association between higher education level and improved survival after esophageal cancer surgery, independent of established prognostic factors. The associations were stronger in patients of an early tumor stage and squamous cell carcinoma