BACKGROUND: Although modifiable risk factors have been included in previous models that estimate or project breast cancer risk, there remains a need to estimate the effects of changes in modifiable risk factors on the absolute risk of breast cancer. METHODS: Using data from a case-control study of women in Italy (2569 case patients and 2588 control subjects studied from June 1, 1991, to April 1, 1994) and incidence and mortality data from the Florence Registries, we developed a model to predict the absolute risk of breast cancer that included five non-modifiable risk factors (reproductive characteristics, education, occupational activity, family history, and biopsy history) and three modifiable risk factors (alcohol consumption, leisure physical activity, and body mass index). The model was validated using independent data, and the percent risk reduction was calculated in high-risk subgroups identified by use of the Lorenz curve. RESULTS: The model was reasonably well calibrated (ratio of expected to observed cancers = 1.10, 95% confidence interval [CI] = 0.96 to 1.26), but the discriminatory accuracy was modest. The absolute risk reduction from exposure modifications was nearly proportional to the risk before modifying the risk factors and increased with age and risk projection time span. Mean 20-year reductions in absolute risk among women aged 65 years were 1.6% (95% CI = 0.9% to 2.3%) in the entire population, 3.2% (95% CI = 1.8% to 4.8%) among women with a positive family history of breast cancer, and 4.1% (95% CI = 2.5% to 6.8%) among women who accounted for the highest 10% of the total population risk, as determined from the Lorenz curve. CONCLUSIONS: These data give perspective on the potential reductions in absolute breast cancer risk from preventative strategies based on lifestyle changes. Our methods are also useful for calculating sample sizes required for trials to test lifestyle interventions.
BACKGROUND: Although modifiable risk factors have been included in previous models that estimate or project breast cancer risk, there remains a need to estimate the effects of changes in modifiable risk factors on the absolute risk of breast cancer. METHODS: Using data from a case-control study of women in Italy (2569 case patients and 2588 control subjects studied from June 1, 1991, to April 1, 1994) and incidence and mortality data from the Florence Registries, we developed a model to predict the absolute risk of breast cancer that included five non-modifiable risk factors (reproductive characteristics, education, occupational activity, family history, and biopsy history) and three modifiable risk factors (alcohol consumption, leisure physical activity, and body mass index). The model was validated using independent data, and the percent risk reduction was calculated in high-risk subgroups identified by use of the Lorenz curve. RESULTS: The model was reasonably well calibrated (ratio of expected to observed cancers = 1.10, 95% confidence interval [CI] = 0.96 to 1.26), but the discriminatory accuracy was modest. The absolute risk reduction from exposure modifications was nearly proportional to the risk before modifying the risk factors and increased with age and risk projection time span. Mean 20-year reductions in absolute risk among women aged 65 years were 1.6% (95% CI = 0.9% to 2.3%) in the entire population, 3.2% (95% CI = 1.8% to 4.8%) among women with a positive family history of breast cancer, and 4.1% (95% CI = 2.5% to 6.8%) among women who accounted for the highest 10% of the total population risk, as determined from the Lorenz curve. CONCLUSIONS: These data give perspective on the potential reductions in absolute breast cancer risk from preventative strategies based on lifestyle changes. Our methods are also useful for calculating sample sizes required for trials to test lifestyle interventions.
Authors: Steven R Cummings; Jeffrey A Tice; Scott Bauer; Warren S Browner; Jack Cuzick; Elad Ziv; Victor Vogel; John Shepherd; Celine Vachon; Rebecca Smith-Bindman; Karla Kerlikowske Journal: J Natl Cancer Inst Date: 2009-03-10 Impact factor: 13.506
Authors: Jeffrey A Tice; Steven R Cummings; Rebecca Smith-Bindman; Laura Ichikawa; William E Barlow; Karla Kerlikowske Journal: Ann Intern Med Date: 2008-03-04 Impact factor: 25.391
Authors: Montserrat Garcia-Closas; Nathaniel Rothman; Jonine D Figueroa; Ludmila Prokunina-Olsson; Summer S Han; Dalsu Baris; Eric J Jacobs; Nuria Malats; Immaculata De Vivo; Demetrius Albanes; Mark P Purdue; Sapna Sharma; Yi-Ping Fu; Manolis Kogevinas; Zhaoming Wang; Wei Tang; Adonina Tardón; Consol Serra; Alfredo Carrato; Reina García-Closas; Josep Lloreta; Alison Johnson; Molly Schwenn; Margaret R Karagas; Alan Schned; Gerald Andriole; Robert Grubb; Amanda Black; Susan M Gapstur; Michael Thun; William Ryan Diver; Stephanie J Weinstein; Jarmo Virtamo; David J Hunter; Neil Caporaso; Maria Teresa Landi; Amy Hutchinson; Laurie Burdett; Kevin B Jacobs; Meredith Yeager; Joseph F Fraumeni; Stephen J Chanock; Debra T Silverman; Nilanjan Chatterjee Journal: Cancer Res Date: 2013-03-27 Impact factor: 12.701