Tumor Characteristics Associated With Mammographic Detection of Breast Cancer in the Ontario Breast Screening Program

Tumor Characteristics Associated With Mammographic Detection of Breast Cancer in the Ontario Breast Screening Program
Victoria A. Kirsh, Anna M. Chiarelli, Sarah A. Edwards, Frances P. O'Malley, Rene S. Shumak, Martin J. Yaffe, and Norman F. Boyd
J. Natl. Cancer Inst. published 3 May 2011, 10.1093/jnci/djr138

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Results:
Both true and missed interval cancers were of higher stage and grade than matched screen-detected breast cancers. However, true interval cancers had a higher mitotic index (OR = 3.13, 95% CI = 1.81 to 5.42), a higher percentage of nonductal histology (OR = 1.94, 95% CI = 1.05 to 3.59), and were more likely to be both estrogen receptor–negative (OR = 2.09, 95% CI = 1.32 to 3.30) and progesterone receptor–negative (OR = 2.49, 95% CI = 1.68 to 3.70) compared with matched screen-detected tumors.

Conclusions:
In this study, interval cancers were of higher stage and grade compared with screen-detected cancers. True interval cancers were more likely to have additional adverse prognostic features of estrogen and progesterone receptor negativity and nonductal morphology. The findings suggest a need for more sensitive screening modalities to detect true interval breast cancers and different approaches for early detection of fast-growing tumors.