Impact of a False-Positive Screening Mammogram on Subsequent Screening Behavior and Stage at Breast Cancer Diagnosis

Abstract

Background: Experiencing a false positive (FP) screening mammogram is economically, physically, and emotionally burdensome, which may affect future screening behavior by delaying the next scheduled mammogram or by avoiding screening altogether. We sought to examine the impact of a FP screening mammogram on the subsequent screening mammography behavior.Methods: Delay in obtaining subsequent screening was defined as any mammogram performed more than 12 months from index mammogram. The Kaplan-Meier (product limit) estimator and Cox proportional hazards model were used to estimate the unadjusted delay and the hazard ratio (HR) of delay of the subsequent screening mammogram within the next 36 months from the index mammogram date.Results: A total of 650,232 true negative (TN) and 90,918 FP mammograms from 261,767 women were included. The likelihood of a subsequent mammogram was higher in women experiencing a TN result than women experiencing a FP result (85.0% vs. 77.9%, P < 0.001). The median delay in returning to screening was higher for FP versus TN (13 months vs. 3 months, P < 0.001). Women with TN result were 36% more likely to return to screening in the next 36 months compared with women with a FP result HR = 1.36 (95% CI, 1.35-1.37). Experiencing a FP mammogram increases the risk of late stage at diagnosis compared with prior TN mammogram (P < 0.001).Conclusions: Women with a FP mammogram were more likely to delay their subsequent screening compared with women with a TN mammogram.Impact: A prior FP experience may subsequently increase the 4-year cumulative risk of late stage at diagnosis. Cancer Epidemiol Biomarkers Prev; 26(3); 397-403. ©2017 AACR.

Figure 1

Primary and secondary analyses design overview FP vs TN. The first arrow represents the index mammogram (true negative and false positive mammograms only). The shaded area represents the first 12 months after index mammogram and index date (T=0) was defined at the end of the shaded area. Mammograms that were followed by a screening mammogram within 12 months were excluded. The second arrow represents the subsequent mammogram after index mammogram. For the secondary analyses the cumulative risk of late stage at diagnosis was estimated over a 4 years period following the index mammogram.

Figure 2

Kaplan-Meier estimates for time to next screen in months by index mammogram result