PhD defence V.D.V. (Valérie) Sankatsing

Mammography screening can result in early detection and possibly earlier treatment and better prognosis of breast cancer. In the Netherlands, women aged 50-74 are invited biennially to digital mammography screening. The aim of this thesis was to quantify the effects of current screening in the Netherlands and to determine the effects and cost-effectiveness of alternative screening strategies, using micro-simulation modelling.

With respect to current screening, we found that digital mammography leads to the detection of more breast cancers than film-screen mammography, but also to more referrals and false-positives. The number of cancers  detected during the screening interval is unaffected, compared to film-screen mammography. Further, we found that the breast cancer mortality rate in the Netherlands decreased by 30% since the introduction of screening until 2010, in women aged 55-74 years. Mammography screening and (improvements in) adjuvant therapy contributed to this decrease.

Using microsimulation, we showed that earlier screening, starting between 40-50 years, is cost-effective and increases the screening benefit, especially in women with a high relative risk of breast cancer, but at the same time results in more false-positives. In addition, we found that triennial screening in women with a low relative risk results in a better balance of benefits and harms than biennial screening. Finally, we found that the rather new technique digital breast tomosynthesis, which creates a pseudo 3D breast image, has a lower chance of being cost-effective than digital mammography. However, at a slightly higher cost-effectiveness threshold than currently used, tomosynthesis becomes more cost-effective than digital mammography.

Due to corona, the PhD defences do not take place publicly in the usual way in the Senate Hall or in the Professor Andries Querido Room. The candidates will defend their dissertation either in a small group or online.