[30] Breast density as a predictor of invasive events after treatment for ductal carcinoma in situ. Hwang E-SS, Miglioretti DL, Lahiff M, Barbash-Ballard R, Kerlikowske K.. University of California, San Francisco, San Francisco, CA; Group Health Center for Health Studies, Seattle, WA; University of California, Berkeley, Berkeley, CA; National Cancer Institute, Bethesda, MD Background: Invasive tumor events following treatment for ductal carcinoma in situ (DCIS) are associated with both treatment- and tumor-related factors. However, it is unknown whether stromal factors may promote DCIS progression. This study investigates whether breast density is an independent predictor of subsequent breast events among women treated for DCIS. Population: Prospective cohort study of women enrolled in the Breast Cancer Surveillance Consortium (BCSC) mammography registry. All women selected for the study had been diagnosed with DCIS with no history of breast cancer prior to DCIS diagnosis and had an American College of Radiology Breast Imaging Reporting and Data System (BI-RADSŪ) breast density measure recorded as part of mammographic screening. Methods: All breast cancer events were ascertained through tumor registries or pathology databases. Both ipsilateral and contralateral events were recorded. Cox proportional hazard model was used to compare adjusted risk of breast cancer among women with high (BI-RADSŪ 3 or 4) versus low (BI-RADSŪ 1 or 2) breast density. Results: Of 4232 women diagnosed with DCIS, 2728 underwent partial mastectomy. During a median follow-up period of 37 months, 115 women developed invasive breast cancer. After adjusting for age and radiation, high breast density was associated with increased hazard for contralateral (HR 2.14; 95% CI 1.10-4.15) but not ipsilateral (HR 0.85; 95% CI 0.44-1.64) subsequent invasive events. Ipsilateral risk for invasive cancer was not increased in those who did not undergo radiotherapy after lumpectomy (HR 0.94; 95% CI 0.44-2.00) or those that underwent radiotherapy (HR 0.56; 95% CI 0.15-2.09). High breast density was not significantly associated with increased hazard of contralateral DCIS (HR 1.44; 95% CI 0.66-3.13). Conclusion: High breast density was an independent predictor of contralateral, but not ipsilateral invasive breast cancer following treatment for DCIS. These findings suggest that women with high breast density undergoing treatment for DCIS may especially benefit from anti-estrogenic therapy to reduce risk of contralateral disease. SABCS 2006 Remember we are NOT Doctors and have NO medical training. This site is like an Encylopedia - there are many pages, many links on many topics. Support our work with any size DONATION - see left side of any page - for how to donate. You can help raise awareness of CAM.