Cancer survival in New South Wales, Australia: socioeconomic disparities remain despite overall improvements

Julia F. Stanbury, Peter D. Baade, Yan Yu, Xue Qin Yu

Disparities in cancer survival by socioeconomic status have been reported previously in Australia. We investigated whether those disparities have changed over time. We used population-based cancer registry data for 377,493 patients diagnosed with one of 10 major cancers in New South Wales (NSW), Australia. Patients were assigned to an area-based measure of socioeconomic status. Five-year relative survival was estimated for each socioeconomic quintile in each 'at risk' period (1996-2000 and 2004-2008) for the 10 individual cancers. Poisson-regression modelling was used to adjust for several prognostic factors. The relative excess risk of death by socioeconomic quintile derived from this modelling was compared over time. Although survival increased over time for most individual cancers, Poisson-regression models indicated that socioeconomic disparities continued to exist in the recent period. Significant socioeconomic disparities were observed for stomach, colorectal, liver, lung, breast and prostate cancer in 1996-2000 and remained so for 2004-2008, while significant disparities emerged for cervical and uterus cancer in 2004-2008 (although the interaction between period and socioeconomic status was not significant). About 13.4 % of deaths attributable to a diagnosis of cancer could have been postponed if this socioeconomic disparity was eliminated. While recent health and social policies in NSW have accompanied an increase in cancer survival overall, they have not been associated with a reduction in socioeconomic inequalities.