Less Favorable Characteristics for Breast Cancer Diagnosed After Biennial vs Annual Screening in Premenopausal Women


Key Points

  • Among premenopausal women, biennial mammography screeners were more likely to have tumors with adverse prognostic features.
  • Among postmenopausal women not taking hormone therapy, there was no difference in the risk for adverse prognostic features.

In a study reported in JAMA Oncology, Miglioretti et al found that diagnosis of breast cancer after biennial vs annual mammography screening was associated with a higher risk of less favorable tumor prognostic characteristics among premenopausal women. They also noted a nonsignificantly higher risk among postmenopausal women receiving hormone therapy and no difference among postmenopausal women not receiving hormone therapy.

Study Details

The study involved data from 15,440 women aged 40 to 85 years with breast cancer diagnosed within 1 year (11–14 months) of an annual or 2 years (23–26 months) of a biennial screening mammogram in a prospective cohort from 1996 to 2012 at Breast Cancer Surveillance Consortium facilities. Less favorable prognostic characteristics were defined as tumors that were stage IIB or higher, tumor size > 15 mm, positive nodes, and any one or more of these characteristics.

In the cohort, most women were aged ≥ 50 years (85.4%), white (78.1%), and postmenopausal (63.6%). Overall, 12,070 were annual screeners, and 3,370 were biennial screeners. Biennial screeners were more likely to be in the youngest (40–49 years) and oldest age groups (70–85 years) and were less likely to have a family history of breast cancer.

For annual and biennial screeners, 12.6% and 14.9% were premenopausal, 42.5% and 40.1% were postmenopausal without hormone therapy use, 21.8% and 21.0% were postmenopausal with hormone therapy use, and 23.1% and 23.9% had surgical menopausal or unknown status. Screen-detected cancers accounted for 77.8% of cancers in annual screeners and 72.8% of those in biennial screeners.

Risk for Adverse Characteristics

In analysis adjusting for race/ethnicity, family history, and registry, among premenopausal women, biennial screeners had a higher risk of tumors of stage ≥ IIB (relative risk [RR] = 1.28, P = .04), size > 15 mm (RR = 1.21, P = .002), and any less favorable prognostic characteristic (RR = 1.11, P = .047). Among postmenopausal women currently taking hormone therapy, biennial screeners had a nonsignificantly higher risk of stage ≥ IIB tumors (RR = 1.14, P = .29), size > 15 mm (RR = 1.13, P = .09), node-positive disease (RR = 1.18, P = .09), and any less favorable characteristic (RR = 1.12, P = .053).

No significant differences were observed according to the type of hormone therapy. In addition, there were no significant differences in the risk for less-favorable prognostic factors for biennial vs annual screeners among women not receiving hormone therapy (eg, RR = 1.03, P = .45, for any characteristic). Overall, there was no significant difference between biennial and annual screeners in the risk for any less-favorable characteristic within any 10-year age group.

The investigators concluded: “Premenopausal women diagnosed as having breast cancer following biennial vs annual screening mammography are more likely to have tumors with less favorable prognostic characteristics. Postmenopausal women not using hormone therapy who are diagnosed as having breast cancer following a biennial or annual screen have similar proportions of tumors with less favorable prognostic characteristics.”

The American Cancer Society supported the study.

Diana L. Miglioretti, PhD, of the University of California–Davis School of Medicine, is the corresponding author of the JAMA Oncology article.

The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.