Tehran University of Medical Sciences Iranian Journal of Public Health 2251-6085 49 11 2020 10 27 2205 2213 Sahar ROSTAMI Department of Reproductive Health and Midwifery, School of Nursing and Midwifery, Tehran University of Medical Sciences, Tehran, Iran AND Cancer Research Center, Cancer Institute of Iran, Tehran University of Medical Sciences, Tehran, Iran Ali RAFEI Cancer Research Center, Cancer Institute of Iran, Tehran University of Medical Sciences, Tehran, Iran Maryam DAMGHANIAN Nursing and Midwifery Care Research Center, Tehran University of Medical Sciences, Tehran, Iran Zohreh KHAKBAZAN Nursing and Midwifery Care Research Center, Tehran University of Medical Sciences, Tehran, Iran Farzad MALEKI Cancer Research Center, Cancer Institute of Iran, Tehran University of Medical Sciences, Tehran, Iran AND Social Determinants of Health Research Center, Urmia University of Medical Sciences, Urmia, Iran Kazem ZENDEHDEL Cancer Research Center, Cancer Institute of Iran, Tehran University of Medical Sciences, Tehran, Iran AND Cancer Biology Research Center, Cancer Institute of Iran, Tehran University of Medical Sciences, Tehran, Iran AND Breast Disease Research Center, Cancer Institute of Iran, Tehran University of Medical Sciences, Tehran, Iran 2018 12 14 2019 04 23 Background: The Gail model is the most well-known tool for breast cancer risk assessment worldwide. Although it was validated in various Western populations, inconsistent results were reported from Asian populations. We used data from a large case-control study and evaluated the discriminatory accuracy of the Gail model for breast cancer risk assessment among the Iranian female population. Methods: We used data from 942 breast cancer patients and 975 healthy controls at the Cancer Institute of Iran, Tehran, Iran, in 2016. We refitted the Gail model to our case-control data (the IR-Gail model). We compared the discriminatory power of the IR-Gail with the original Gail model, using ROC curve analyses and estimation of the area under the ROC curve (AUC). Results: Except for the history of biopsies that showed an extremely high relative risk (OR=9.1), the observed ORs were similar to the estimates observed in Gail's study. Incidence rates of breast cancer were extremely lower in Iran than in the USA, leading to a lower average absolute risk among the Iranian population (2.78, ±SD 2.45). The AUC was significantly improved after refitting the model, but it remained modest (0.636 vs. 0.627, ΔAUC = 0.009, bootstrapped P=0.008). We reported that the cut-point of 1.67 suggested in the Gail study did not discriminate between breast cancer patients and controls among the Iranian female population. Conclusion: Although the coefficients from the local study improved the discriminatory accuracy of the model, it remained modest. Cohort studies are warranted to evaluate the validity of the model for Iranian women. https://ijph.tums.ac.ir/index.php/ijph/article/view/15607 https://ijph.tums.ac.ir/index.php/ijph/article/download/15607/7049