Screening mammography in old women saves lives: A simulation model

Abstract

10561 Background: Screening mammography has shown to decrease breast cancer specific death rate by 20–25% and has been recommended in women aged 40 and above, nevertheless, some country service screen programs stop screening in women older than 69, even though the sensitivity and specificity of screening mammography is highest in older women, especially those older than 80 years. The size of the older population is growing exponentially and old women have the highest incidence of breast cancer; one third of breast cancer diagnosis and half the deaths of breast cancer in USA occurred in women aged 70 and above in the year 2000. The aim of this study is to estimate the impact of mammographic screening in women aged 70 and above on breast cancer mortality. Methods: US Census, SEER, CISNET, CDC, HMD, ULTD databases were searched to obtain population data and rates of incidence and mortality of breast cancer by age. In addition, mammography screening bibliography from randomized clinical trials, meta-analysis, and service health programs publications were reviewed to estimate the impact of screening mammography on results for different strata. Analytical and simulation methods were applied for modeling the data with the aid of Mathematica to calculate breast cancer reduction rate. Results: A reduction in breast cancer mortality was observed with a magnitude proportional to age, even after taking into account competing risks of death by other causes in the aging population. Simulation of different scenarios revealed a decrease in breast cancer mortality in the range of 5 to15% for women younger than 50 years, 15 to 25% in the group of women aged 50 to 69, and 25 to 35% in women older than 69. Factors such as population life expectancy, breast cancer incidence, attrition rate in screening or cross-over, overall specificity of mammographic detection, interval of screening, impact the estimations, explaining in part some of the negative results of prevention trials. Conclusions: Reduction of breast cancer mortality by mammographic screening is proportional to age. Women aged 70 and above benefit more from mammographic screening than younger women. No significant financial relationships to disclose.