BREAST, LUNG AND COLORECTAL-CANCER INCIDENCE AND SURVIVAL IN SOUTH THAMES REGION, 1987-1992 - THE EFFECT OF SOCIAL DEPRIVATION

Background This paper describes the relationship between social depriv ation and incidence of, and survival from, breast, lung, and colorecta l cancers among residents of the South Thames regions. We analysed 23 505 cases of breast cancer, 29 903 cases of lung cancer and 21 905 cas es of colorectal cancer, aged 40-99 inclusive at diagnosis and diagnos ed between 1 January 1987 and 31 December 1992. Methods Using the 1991 Census in conjunction with the Townsend index on social deprivation, we derived proxy indicators of deprivation based on patients' home pos tal codes. Cumulative relative five-year survival rates (per cent) wer e calculated for each cancer. We then compared our results with the re levant standardized incidence and mortality ratios by deprivation stat us. Results A clear trend was observed in standardized mortality rates across deprivation tenths for the three tumour sites: mortality incre ased with deprivation. A strong positive correlation was found between deprivation and the incidence of lung cancers (p < 0.0001), but no as sociation was found between deprivation and incidence of breast and co lorectal cancers. Significantly lower five-year relative survival rate s were found for breast and colorectal cancer patients in the most dep rived Townsend tenths. Breast cancer patients resident in the most aff luent tenth of enumeration districts had a 70 per cent relative surviv al ratio compared with 57 per cent in the most deprived tenth. The cor responding figures for colorectal cancer patients were 40 per cent and 32 per cent, respectively. Conclusion Survival differences by depriva tion status exist in South Thames among patients suffering from breast or colorectal cancers and are not explained by differences in the inc idences of these diseases. For lung cancer, incidence and mortality we re positively correlated with deprivation, but no socio-economic gradi ent was found for survival.