Modeling study: Screening, treatment effects on breast cancer mortality vary by subtype

Decreases in breast cancer mortality between 2000 and 2012 were associated with advances in screening and adjuvant therapy but varied by breast cancer molecular subtype, according to a simulation modeling study.

The estimated rate of reduction in overall breast cancer mortality in 2000 was 37% from an estimated baseline rate of 64 deaths per 100,000 women, with 44% and 56% of that associated with screening and treatment, respectively. In 2012 the estimated reduction was 49% from an estimated baseline rate of 63 per 100,000 women, with 37% and 63% associated with screening and treatment, respectively (estimated 12% difference in 2012 vs. 2000), Sylvia K. Plevritis, PhD, of Stanford (Calif.) University and her colleagues reported in JAMA.

Screening and treatment were estimated to contribute to the reductions at varying rates. For example, the relative contributions of screening vs. treatment were 36% vs. 64% for ER+/ERBB2– disease; 31% vs. 69% for ER+/ERBB2+ disease; 40% vs. 60% for ER–/ERBB2+ disease; and 48% vs. 52% for ER–/ERBB2– disease.

The model-based analysis provides clinically relevant insights about the contributions of screening and treatment to reductions in breast cancer mortality by molecular subtype, showing a greater relative contribution of treatment in 2012 overall and for all subtypes except ER–/ERBB2– disease, the authors said.

“Because ER+ cancers are the most prevalent and this group is expected to increase with time, additional advances for this subtype could have the largest effect on reducing the overall population burden of breast cancer,” they noted.

This study was supported by grants from the National Cancer Institute and the American Cancer Society. Dr. Plevritis reported consulting for GRAIL.

sworcester@frontlinemedcom.com

SOURCE: Plevritis S et al. JAMA. 2018 Jan 9;319(2):154-64. doi: 10.1001/jama.2017.19130.

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