Breast cancer mortality climbs with age at diagnosis in postmenopausal women

Risk of death from breast cancer rises with increasing age at diagnosis, according to a new study of more than 1 000 postmenopausal women with potentially curable breast cancer. Cumulative mortality from breast cancer over 5 years was 5.7% for women under 65, 6.3% for women aged 65 - 74, and 8.3% for women 75 or over. The trend wasn’t fully explained by differences in tumour characteristics or treatments. In fully adjusted analyses, women over 75 at diagnosis were still 63% more likely to die of breast cancer than women under 65 (hazard ratio 1.63, 95% CI 1.23 - 2.16). All participants had hormone-receptor positive cancers.

As expected, older women were also more likely than younger women to die of other things, and only a third of the deaths in women over 75 at diagnosis resulted from breast cancer. It is this proportion (which is much bigger in younger women) that may have led people to believe that breast cancer was less dangerous in older women, say the authors. These analyses suggest the opposite – that older age at diagnosis is an independent risk factor for death from breast cancer in postmenopausal women. Further work is needed to find out why.

Van der Water W et al. JAMA 2012;307(6):590-597;doi:10.1001/jama.2012.84