Letter in response: breast cancer screening of women aged 70–74 years

Abstract

The purpose of this study is to critically appraise the claim by Nickson et al. [1] that they have evidence supporting the Australian Government’s recent decision to extend the national free invitation for biennial mammography program (BreastScreen) to women aged 70–74 years. Since their claim was made on the basis of a significant difference in the incidence of larger primary breast cancers between women in this age group who are already participating in BreastScreen versus those who are not, an analysis of the stage at diagnosis of breast cancer in the USA versus mammographic screening over 30 years, evidence from breast cancer adjuvant endocrine and chemotherapy (adjuvant therapy) trials and data from an evaluation of BreastScreen and adjuvant therapy use in Australia were examined. By 1999, most Australian women aged 40–79 years were receiving adjuvant therapy that could cure breast cancer no matter what the size of the primary cancer. Further, the incidence primary breast cancers of all sizes had doubled in the USA during 30 years of mammographic screening, but the incidence of more advanced breast cancers had almost remained constant, indicating that adjuvant therapy, not mammographic screening, was the main cause of the 28 % reduction in breast cancer mortality that had been observed. In conclusion, the claim by Nickson et al. is not supported by available evidence. Further, BreastScreen should not have been extended to these older women before the UK trial, which is testing the efficacy of mammographic screening of women aged 70–74 years [8], had reported its results.