Disparities in survival of stomach cancer among different socioeconomic groups in North-East Netherlands

Background: Survival differences in stomach cancer are depended on patient, tumour and treatment factors. Some populations are more prone to develop stomach cancer, such as people with low socioeconomic status (SES). The aim of this population based study was to assess whether differences in socioeconomic status (SES) alone, after adjusting for confounding factors, also influence survival. Methods: From 1989 to 2007 all patients with stomach cancer were selected from the cancer registry of the Comprehensive Cancer Centre North-East. Postal code at diagnosis was used to determine SES, dividing patients in three groups; low, intermediate and high SES. Associations between age, localization, grade, stage, and treatment were determined using Chi-square analysis. Relative survival analysis was used to estimate relative excess risk (RER) of dying according to SES. Results: In low SES neighbourhoods diagnosis was established at older age. More distal tumours were detected in patients with low SES, whereas pathology showed more poorly differentiated tumours in patients with high SES. Overall, more resections were performed in, and more chemotherapy was administrated to patients in high SES neighbourhoods. After adjusting for confounding factors, the risk of dying was lower for patients with high SES (RER 0.89, 95% Confidence Interval 0.81-0.98) compared to patients with low SES. Conclusion: SES proved to be an independent prognostic factor for survival in patients with stomach cancer.