Quantifying the benefits and harms of treating ductal carcinoma in situ for use in the economic evaluation of breast cancer screening programmes

Abstract

Mammography screening is deemed cost-effective for women aged 50-70. Yet the utilities informing breast screening policy are limited in their ability to adequately capture the benefits and risks. The evaluation of many cancer screening programmes present results in terms of cost per QALY but fail to include any disutility for the patients who have been over-diagnosed and may receive unnecessary treatment. This thesis presents an overview of the challenges associated with valuing breast cancer states, using the results of an empirical study deriving utilities from 172 women in Melbourne, Australia as an example of potential methods to capture the disutility of overtreatment.

Ductal carcinoma in situ was used as a proxy to quantify the benefits and harms associated with the sequelae of screening. Utilities derived from 172 women for health states explicitly describing overdiagnosis were lower than those from the literature, where it is unlikely that women were informed that their treatment may have been unnecessary. Qualitative interviews of 26 patients validated that this risk was important in the valuation of treatment. The findings were used to inform an economic model which demonstrated that the explicit inclusion of the harms of screening may change the decision on breast screening strategy.