Survival and degree of spread for female breast cancers in New South Wales from 1980 to 2003: implications for cancer control

Abstract

This study investigated associations of degree of spread at diagnosis of breast cancer and socio-demographic factors with the risk of death among NSW females diagnosed in 1980-2003. Trends by diagnostic period, socio-demographic differences, and the implications for cancer control were considered. NSW Central Cancer Registry data were analyzed using regression and rank-order tests to show predictors of death from breast cancer and trends in degree of spread. Compared with localized disease, case fatality was thrice and 14 times higher for cancers with regional spread and distant metastases, respectively. After adjusting for degree of spread and socio-demographic differences, the relative risk of death from breast cancer has declined in recent diagnostic periods compared with the 1980-1983 baseline, reaching a low of 0.38 (0.35, 0.40) for 1999-2003. Age-specific analyses indicated that relative risks were lower in 1999-2003 for 50-69 year olds (RR = 0.31) than younger (RR = 0.40), or older (RR = 0.46) females. Regional or distant disease at diagnosis was lowest in the older age groups, the highest socio-economic stratum and in more recent periods. Females born in non-English speaking countries presented with more advanced disease, as did metropolitan women with the highest access to health services. Degree of spread of cancer at diagnosis is a powerful predictor of case fatality. Case fatalities from breast cancer have declined by diagnostic period, after adjusting for degree of spread, which may reflect treatment and screening advances. Attention should be directed at reducing disparities by socio-economic status and encouraging migrant women to present earlier.