Risk of Interval Invasive Second Breast Cancers

Key Points

  • Median 5-year interval cancer risk was 1.4%, with 155 of women having ≥ 3% risk.
  • Factors associated with higher risk included age < 40 years at primary diagnosis, pre- or perimenopausal status during surveillance, and hormone receptor–negative primary breast cancer.  

In a study reported in the Journal of Clinical Oncology, Lee et al determined risk levels for interval invasive second breast cancers after negative surveillance mammography and identified factors associated with higher risk. 

Study Details

The study involved 65,084 surveillance mammograms from 18,366 women with a primary breast cancer diagnosis of unilateral ductal carcinoma in situ or stage I to III invasive breast carcinoma performed between 1996 and 2012 in the Breast Cancer Surveillance Consortium. Interval invasive disease was defined as ipsilateral or contralateral cancer diagnosed within 1 year after a negative surveillance mammogram.

Interval Cancer Risks

Overall, there were 474 surveillance-detected cancers, including 334 invasive and 140 ductal carcinoma in situ cases, and 186 interval invasive cancers, yielding a cancer detection rate of 7.3 per 1,000 examinations and an interval invasive cancer rate of 2.9 per 1,000 examinations.

The median cumulative 5-year interval cancer risk was 1.4% (10th to 90th percentile range = 0.5%–3.7%), with 15% of women having ≥ 3% 5-year interval cancer risk. Cumulative 5-year risk was highest among women aged < 40 years at primary breast cancer diagnosis (3.6%), those who were pre- or perimenopausal during surveillance (2.6%), those who had estrogen receptor– and progesterone receptor–negative primary breast cancer (2.6%), those who had interval presentation of primary breast cancer (2.2%), and those who underwent breast conservation without radiation (1.8%).

The investigators concluded, “Risk of interval invasive second breast cancer varies across women and is influenced by characteristics that can be measured at initial diagnosis, treatment, and imaging. Risk prediction models that evaluate the risk of cancers not detected by surveillance mammography should be developed to inform discussions of tailored surveillance.”

The study was funded by a Breast Cancer Surveillance Consortium Program Project grant and by the National Cancer Institute.

Janie M. Lee, MD, of Seattle Cancer Care Alliance, University of Washington, is the corresponding author for the Journal of Clinical 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®.


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