TY - JOUR T1 - Population-based Relative Risks for Specific Family History Constellations of Breast Cancer - Towards Individualized Risk Estimation JF - bioRxiv DO - 10.1101/136051 SP - 136051 AU - Frederick S. Albright AU - Leigh Neumayer AU - Saundra S. Buys AU - Cindy B. Matsen AU - Kimberly A. Kaphingst AU - Lisa A. Cannon-Albright Y1 - 2017/01/01 UR - http://biorxiv.org/content/early/2017/05/10/136051.abstract N2 - Background: Estimated Relative Risks (RR) for breast cancer in relatives of breast cancer cases are typically not based on precise family history. Using a large resource linking deep genealogy with decades of cancer data, RRs were estimated for breast cancer based on specific and extended family history.Methods: RRs for breast cancer were estimated in females with breast cancer family histories that included number of first-(FDR), second-(SDR), and third-degree relatives (TDR), and age at earliest diagnosis in a relative. Relative risks were based on breast cancer rates estimated from 265,677 females in the resource with no FDR, SDR or TDR family history of breast cancer.Results: RRs for first-degree relatives of BC cases ranged from 2.22 (=1 FDR affected, CI: 2.14, 2.29) to 7.91 (=4 FDRs affected, CI: 5.26, 11.43). RRs for second degree relatives of probands with 0 affected FDRs ranged from 1.49 (>1 SDR affected, CI: 1.44, 1.54) to 2.60 (>4 SDRs affected, CI: 1.91, 3.46). RRs for third-degree relatives with 0 affected FDRs and 0 affected SDRs ranged from 1.22 (>1 TDR affected, CI: 1.18, 1.26) to 1.93 (>5 TDRs affected, CI: 1.62, 2.28). Increased RRs were observed for decreasing earliest age at diagnosis in a relative.Conclusions: The majority of women have a positive family history for breast cancer; any number of affected relatives significantly increases risk for breast cancer. Risk prediction derived from specific and extended family history allows identification of women at highest risk and could be a powerful, efficient tool to individualize cancer prevention and screening.Financial Support: Research was supported by the Utah Cancer Registry, which is funded by Contract No.HHSN261201000026C from the National Cancer Institute's SEER Program with additional support from the Utah State Department of Health and the University of Utah. Partial support for all data sets within the Utah Population Database (UPDB) and for LACA was provided by Huntsman Cancer Institute, Huntsman Cancer Foundation, University of Utah, and the Huntsman Cancer Institute's Cancer Center Support grant, P30 CA42014, from National Cancer Institute. ER -