The relationship between knowledge of family history and cancer characteristics at diagnosis in women newly-diagnosed with invasive breast cancer

Aim To document the prevalence of family history of breast cancer (BC) amongst women newly-diagnosed with invasive BC and to explore the relationship between family history and cancer size and stage. Methods A cross-sectional analysis was conducted on baseline questionnaire data from a cohort study of 1,684 women diagnosed with invasive BC within the previous 12 months and recruited between 2004 and 2006 in Victoria, Australia. Results Women with affected first degree relative(s) were more likely to have a smaller BC (odds ratio for ≤10 mm 1.74, 95% CI: 1.32–2.29) and stage I BC (odds ratio 1.31, 95% CI: 1.01–1.70) at diagnosis than women with no affected relatives. There was no significant difference in BC size and stage between women with only affected second degree relatives and women with no affected relatives. Conclusions Women with a first degree relative with BC had smaller, earlier stage cancers at diagnosis, possibly reflecting more diligent use of breast screening amongst women who considered themselves at increased risk of developing the disease.