LAUSR

Purpose: To test the hypothesis that prior non-adherence to mammography screening could predict subsequent non-adherence to breast cancer treatment. Specifically, we hypothesized that as compared with adherers, screening non-adherers may be more likely to have delayed surgery, discontinue their adjuvant hormone therapy, and consequently have worse breast cancer outcomes. Methods: We conducted a record-linkage study based on data from the Stockholm Mammography Screening Program (1989-2013), Stockholm-Gotland Breast Cancer Register (2001-2017), Swedish Prescribed Drug Register (2005-2017), and Cause of Death Register (2001-2013). Women diagnosed with breast cancer between 2001 and 2008 in Stockholm, Sweden, were prospectively followed for treatment and survival until December 31st, 2013 (N=5106). Screening non-adherers were defined as patients who were invited but did not attend the screening mammography within 2 years before breast cancer diagnosis. Discontinuation of adjuvant hormone therapy was defined as having any interval between two consecutive dispenses exceeding 180 days during follow-up. Disease-free survival was defined as time to local recurrence, distant metastasis, contralateral breast cancer, or death from breast cancer, whichever came first. Results: The proportion of delayed surgery (≥6 weeks) for screening adherers (restricted to interval cancers only) versus non-adherers were 15.5% versus 20.6%, respectively (P Conclusions: Compared to adherers, screening non-adherers are more likely to have delayed surgery, discontinue their adjuvant hormone therapy, and subsequently have worse breast cancer outcomes even after adjusting for baseline tumor characteristics. Citation Format: He W, Bergman LE, Tornberg S, Strand F, Hall P, Czene K. Non-adherers of mammography screening: Delayed surgery, early discontinuation of adjuvant hormone therapy, and worse breast cancer outcomes [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P6-08-20.