A simulation of the development and screening of Cancer Mammae

Abstract

Based on the tumor growth model of Harald Weedon-Fekjær et al.'s paper "Breast cancer tumor growth estimated through mammography screening data", a simulation of breast cancer occurrence and tumor growth in a large population of women was made. The simulation was made realistic by starting tumor growth according to a Poisson process, including a distribution for clinical detection size and a screening test sensitivity function, and using an individual growth rate, based on estimates of Weedon-Fekjær et al. After running the full simulation, parts of the simulation outcomes were compared to known data of breast cancer and the model was found to give realistic and expected results. The simulation was then used to look for other interesting results such as expected reduction in time to tumor detection due to screening and finding the size distribution of tumors before and after screening. For the age group 50 - 69 years, it was found that screening every year allows a reduction of 19.1 months, while screening every two, three, five and ten years allows for reductions of, respectively, 9.5, 8.3, 6.1 and 3.4 months. These results are based on the assumption that tumors are actually found at screening, i.e. the tumors are not found clinically before they are found on screening. When clinical findings are included, different results are obtained. For the age group 50 - 69 years, it was found that screening every year allows a reduction of 15 months, while screening every two, three, five and ten years allows for reductions of, respectively, 4.8, 1.4, -5.6 and -21.5 months. Negative numbers indicate that a tumor is found earlier clinically than at screening.