Assessing health care use and cost consequences of a new screening modality: the case of digital mammography

Abstract

Background: Full-field digital mammography (FFDM) has largely replaced screen-film mammography (SFM) for breast cancer screening, but how this affects downstream breast-related use and costs is unknown.

Objectives: To compare breast-related health care use and costs among Medicare beneficiaries undergoing SFM versus FFDM from 1999 to 2005.

Design: Retrospective cohort study.

Subjects: Medicare-enrolled women aged 66 and older with mammograms in Breast Cancer Surveillance Consortium registries.

Measures: Subsequent follow-up with additional imaging or breast biopsy within 12 months was ascertained through Medicare claims. Associated mean costs were estimated by screening modality and year, adjusting for confounding factors, and clustering within mammography facilities using Generalized Estimating Equations.

Results: Among 138,199 women, 332,324 SFM and 22,407 FFDM mammograms were analyzed. Approximately 6.5% of SFM and 9.0% of FFDM had positive findings. In 2001, subsequent imaging was higher among FFDM versus SFM (127.5 vs. 97.4 follow-up mammography claims per 1000 index mammograms), whereas subsequent biopsy was lower among FFDM versus SFM (19.2 vs. 24.9 per 1000 index mammograms) with differences decreasing over time. From 2001 to 2004, mammography subsequent to FFDM had higher mean costs than SFM ($82.60 vs. $64.31 in 2001). The only cost differences between SFM and FFDM for ultrasound or biopsy were in 2001.

Conclusions: Subsequent breast-related health care use differed early in FFDM introduction, but diminished over time with differences attributable to higher recall rates for additional imaging and lower rates of biopsy in those undergoing FFDM versus SFM. Remaining cost differences are because of higher reimbursement rates for FFDM versus SFM.

Figure 1

Trends in the adjusted number of women with subsequent claims (separately for mammography (1A), ultrasound (1B), and breast biopsy (1C) and a combined total for any breast-related follow-up (1D)) per 1000 index mammograms, by mammogram result (true positive + false positive (TN+FP), TN, and FP) and screening modality. Full field digital mammography is indicated with white circles and screen film mammography is indicated with black circles.

Figure 2

Trends in the adjusted subsequent costs (separately for mammography (2A), ultrasound (2B), and breast biopsy (2C), and a combined total for any breast-related follow-up (2D)) per index mammogram with non-zero subsequent costs, by mammogram result (true positive + false positive (TN+FP), TN, and FP) and screening modality. Full field digital mammography is indicated with white circles and screen film mammography is indicated with black circles.