Age effects on survival from early breast cancer in clinical settings in Australia.

Background:   The study aim was to determine whether age is an independent risk factor for survival from early invasive breast cancer in contemporary Australian clinical settings.

Methods:   The study included 31 493 breast cancers diagnosed in 1998-2005. Risk of death from breast cancer was compared by age, without and with adjustment for clinical risk factors, using Cox proportional hazard regression.

Results:   Risk of breast cancer death was elevated for cancers of larger size, higher grade, positive nodal status, oestrogen receptor negative status, vascular invasion and multiple foci. Ductal lesions presented a higher risk than other lesions. Adjusting for these factors, the relative risk of breast cancer death (95% confidence limits) was lower for 40-49-year-olds at 0.80 (0.66, 0.96) than for the reference category under 40 years, but higher for 70-79-year-olds at 1.64 (1.36, 1.98) and women aged 80 years or more at 2.19 (1.79, 2.69). The risk for 50-69-year-olds and women under 40 years was similar. Risk-factor adjustment reduced the difference in risk between the reference category under 40 years and 40-49-year-olds, largely eliminated the lower relative risk for 50-69-year-olds, and increased the relative risks for women aged 70-79 years and older.

Discussion:   Survivals in women under 40 and over 70 years of age are poorer than for 40-69-year-olds. Research is needed into the best treatment modalities for younger women and older women with co-morbidity.