Rurality and survival differences in lung cancer: a large population-based multivariate analysis.

Several studies have suggested rural health disadvantages. In France, studies on rural-urban patterns of lung cancer survival have yielded conflicting results. The aim of this analysis was to determine whether rural residence was associated with poor survival in three French counties. The database consisted of all primary lung cancer cases diagnosed in 2000 and 2001 collected through the Doubs cancer registry. A degree of rurality, obtained from socio-demographic and farming parameters of the 1999 French census treated with factor analysis, was attributed to each patient according to his/her place of residence. Among the 802 patients, 21% resided in rural areas, 11% were semi-urban inhabitants and 68% were urban residents. Survival differed significantly between these three rurality categories (p=0.04), with 2-year survival rates of 18, 29 and 24%, respectively. Using a Cox model, rural areas were significantly correlated with poor survival as compared with semi-urban areas (OR=1.42; 95% confidence interval=1.06-1.90; p=0.02). There was no survival difference between semi-urban and urban patients (OR=1.18; 95% confidence interval=0.91-1.53; p=0.21). Patient and tumour characteristics, especially stage and staging procedures, as well as first line treatment, did not vary with the degree of rurality. In conclusion, rurality has to be considered as a strong prognostic factor. Several intricate factors might be hypothesized such as increasing time to diagnosis leading to heavier tumour burden, worse treatment compliance and socioeconomic status. Before practical interventions can be proposed, prospective studies are warranted with further definition of rural risk factors for decreased survival in rural lung cancer patients.