The Impact of a Robust Supplemental Screening Program on False-Negative Rates: Time for New Benchmarks?

Screening mammography false-negative rates (FNRs) measure interval cancers (ICs) that are confounded by asymptomatic false-negative (FN) cancers detected on supplemental screening (SS) examinations. The purpose of this study was to 1) evaluate the impact of SS on FNRs for patients at higher-than-average risk in a robust SS program and 2) compare patient and tumor characteristics of symptomatic ICs and asymptomatic FN cancers.

Screening mammogram audit metrics from an academic institution from July 1, 2018, to June 30, 2023, were retrospectively reviewed. A negative screening mammogram with a subsequent diagnosis of cancer within 12 months was considered an FN cancer. Patient risk, method of detection, SS utilization, and tumor characteristics were collected. Cochran-Mantel-Haenszel tests were used to analyze trends, and univariable tests were used to compare symptomatic and asymptomatic cases.

Of 106 750 screening mammograms, 624 screening-detected cancers and 119 FN cancers were identified, with a cancer detection rate of 5.8/1000 and an FNR of 1.11/1000. There were 53 (45%) symptomatic ICs and 66 (55%) asymptomatic FNs, with a symptomatic FNR of 0.50/1000. Patients with symptomatic IC were more likely to have a personal history of breast cancer (P = .0289), and 74% (39/53) were higher-than-average risk. Symptomatic ICs were larger at diagnosis (mean size 2.3 cm vs 1.5 cm; P = .0293). MRI detected the majority (37/66, 60%) of asymptomatic FNs.

A robust SS program allows for the symptomatic FNR to fall below published national performance benchmarks from the Breast Cancer Surveillance Consortium. Most patients with symptomatic IC were at higher-than-average risk and underutilized SS MRI.