In a study of the use of breast cancer screening modalities in the Medicare population reported in Journal of the National Cancer Institute, Brigid K. Killelea, MD, MPH, FACS, and colleagues at Yale University School of Medicine, Yale Cancer Center, and Yale–New Haven Hospital, New Haven, Connecticut, found significant increases in use of digital image acquisition and computer-aided detection and significantly increased cost of screening between 2001–2002 and 2008–2009 but no difference in breast cancer incidence rates between the two time periods (of detection of early-stage or any-stage cancer during 2 years of folllow-up in the early and later cohorts).¹

Study Details

In the study, early (2001–2002) and late (2009–2009) cohorts of women aged ≥ 66 years without a history of breast cancer were derived from Medicare’s 5% random sample of beneficiaries who lived in a particular Surveillance, Epidemiology, and End Results (SEER) region. Each cohort was followed for 2 years, and women with incident breast cancer were identified.

In total, there were 137,150 women in the early cohort and 133,097 women in the later cohort. The early cohort had a younger mean age (76.0 vs 77.3 years, P < .001) and fewer comorbidities (≥ 3 comorbidities in 10.8% vs 15.6%, P < .001).

Overall, the use of screening mammography increased from 42.0% in the early cohort to 42.6% in the later cohort (P < .001). Large increases were observed in the use of digital image acquisition, from 2.0% to 29.8% (P < .001), and the use of computer-aided detection, from 3.2% to 33.1% (P < .001), whereas the use of film screening mammography decreased from 40.0% to 12.9% (P < .001).

Approximately one-third of women aged ≥ 75 years received screening mammography in both cohorts (32.4% vs 32.6%, P = .35), and the increases in use of digital image acquisition and computer-aided detection in these older women were similar to women under age 75.

Use of diagnostic mammography increased from 5.3% in the early cohort to 7.1% in the later cohort (P < .001), with use of digital imaging increasing from 0.2% to 5.5% and use of computer-aided detection increasing from 0.1% to 4.0% in this setting (P < .001 for both). Breast ultrasound use increased from 4.0% to 4.9% and magnetic resonance imaging use increased from 0.03% to 0.3% (P < .001 for both).

The biopsy rate decreased from 2.0% to 1.7% (P < .001). Use of other imaging techniques decreased from 1.8% to 1.5% (P < .001).

Cost Implications

Screening-related cost per capita, including screening and workup procedures, increased from $76 in the early cohort to $112 in the later cohort (47.4% increase, P < .001). The increase represents an absolute increase in Medicare spending from $666 million in the early period to $962 million in the later period (44% increase). The increased use of digital image acquisition and computer-aided detection contributed most to the increased total cost.

The cost of breast biopsy did not change over the study periods ($23 and $25, P = .75). Screening-related cost per capita increased from $101 to $150 in women aged 67 to 74 years (50% increase, P < .001) and from $58 to 83$ in women aged ≥ 75 years (43% increase, P < .001).

Detection Rates

There were no changes in cancer detection rates between the early and later cohorts overall or by disease stage. The overall incidence rates were 4.22 vs 4.30 per 1,000 person-years for any-stage breast cancer (adjusted rate ratio = 1.04, 95% confidence interval [CI] = 0.96–1.14), 2.45 vs 2.57/1,000 person-years for early stage (in situ and stage I) disease (adjusted rate ratio = 1.07, 95% CI = 0.96–1.20, P = .41), and 0.20 vs 0.23/1,000 person-years for late stage (stage IV) disease (adjusted rate ratio = 1.24, 95% CI = 0.85–1.82). There was no significant change in stage distribution or tumor size over time among the women diagnosed with breast cancer.

The investigators concluded: “In this large, population-based study we observed a 47% increase in per-capita costs associated with breast cancer screening among Medicare beneficiaries from 2001 through 2009 without a statistically or clinically significant difference in the incidence of early-stage breast cancer.”

Cary P. Gross, MD, of Yale University School of Medicine, is the corresponding author for the Journal of the National Cancer Institute article. ■

Disclosure: The study was supported by the National Cancer Institute and Yale Comprehensive Cancer Center. For full disclosures of the study authors, visit jnci.oxfordjournals.org.

Reference

1. Killelea BK, Long JB, Chagpar AB, et al: Evolution of breast cancer screening in the Medicare population: clinical and economic implications. J Natl Cancer Inst 106(8):dju159, 2014.