Resumen
Breast cancer diagnosed between a negative screening mammogram and the next regularly scheduled mammographic exam is called interval breast cancer. It is often diagnosed at more advanced stages than screening-detected cancers. While body mass index (BMI) is a risk factor for postmenopausal breast cancer overall and can influence the accuracy of mammography, the association of BMI with postmenopausal interval breast cancer is unclear. Using data from the Women?s Health Initiative, a national study among postmenopausal women, we found that lower BMI was significantly associated with a higher risk of interval breast cancers diagnosed within 1 year of a negative mammogram after adjustment for multiple risk factors. These findings suggest that obesity is associated with a lower risk of postmenopausal interval breast cancer. Future research using body composition measures is warranted to confirm our findings.