Choice of Assessment and Subsequent Risk of Breast Cancer among Women with False-Positive Mammography Screening

SIMPLE SUMMARY: Women with one or more false-positive results have a two- to four-fold higher risk of subsequently developing breast cancer than women with negative screening results do. This study investigated whether subsequent breast cancer risks are different for different choices of assessments performed after a positive breast cancer screening. This register-based national study showed that women who had an assessment including ‘only ultrasound’ or ‘only additional mammography’ had higher relative risks (RR) of next-round screen-detected cancer of 1.52 (95% CI: 0.93–2.47) and 1.67 (95% CI: 0.54–5.16) compared to those of women who underwent assessments with ultrasound and additional mammography. Invasive assessments (i.e., assessments that included biopsy) that lacked an ultrasound or additional mammography were not associated with an increased risk of subsequently developing cancer, leaving the assessments ‘all three elements’, ‘only additional mammography’, or ‘only ultrasound’ with the highest subsequent risks of breast cancer. It might therefore be important to remind women who are assessed with the above-mentioned assessments to attend subsequent screenings. ABSTRACT: Women with false-positive mammography screening results have a two- to four-fold higher risk of breast cancer. This study aimed to investigate if the subsequent risk of breast cancer after a false-positive mammography screening is associated with the received diagnostic assessment. The study population consisted of women who underwent false-positive mammography screening from January 2010 to June 2019. They were categorised into seven groups depending on the elements in the assessment (standard care: additional mammography, ultrasound, and if they had a relevant biopsy). Risks of interval cancer, next-round screen-detected cancer, and long-term breast cancer for non-standard care assessments were compared to standard care assessments using Binomial and Cox regression models. We included 44,279 women with a false-positive result. Invasive assessments that lacked an ultrasound or additional mammography were not more associated with an increased risk of subsequent cancers compared to that of ‘all three elements’. The few assessments that included ‘only ultrasound’ or ‘only mammography’ resulted in higher relative risks of next-round screen-detected cancer of 1.52 (95% CI: 0.93–2.47) and 1.67 (95% CI: 0.54–5.16), respectively, compared to that of standard care. The increased subsequent risk of breast cancer among women with a previous false-positive result was not found to be correlated with the choice of elements in the assessment process.