The risk of interval invasive second breast cancer — defined as ipsilateral or contralateral cancer diagnosed within 1 year after a negative surveillance mammography — is varied among women within 5 years of primary breast cancer therapy, according to a study published in the Journal of Clinical Oncology.
Breast cancer screening and therapy is becoming increasingly individualized but imaging surveillance post therapy remains very patient nonspecific. Surveillance based on predictors for interval invasive second breast cancer may improve outcomes among women after primary therapy.
For this study, researchers evaluated 65,084 surveillance mammograms obtained between 1996 and 2012 in 18,366 women with unilateral ductal carcinoma in situ or stage I to III invasive breast cancer.
A total of 474 surveillance-detected cancers (334 invasive, 140 ductal carcinoma in situ) and 186 interval invasive cancers were identified. The cancer detection rate was 7.3 per 1000 examinations, and 2.9 per 1000 for interval invasive cancer.
Overall, the median cumulative 5-year interval cancer risk was 1.4%, but this risk increased to 3% or greater among 15% of study patients.
The highest cumulative 5-year interval cancer risk was reported among women who were younger than 40 at primary breast cancer diagnosis, were pre- or perimenopausal during surveillance, had estrogen and progesterone receptor-negative primary breast cancer, interval cancer presentation at primary diagnosis, and were treated with breast conservation without radiation.
The varying risk of interval invasive second breast cancer is affected by characteristics that can be assessed at diagnosis, treatment, and imaging. The authors concluded that “risk prediction models should be developed that evaluate the risk of cancers that are not detected by surveillance mammography to identify women who might benefit most from supplemental surveillance imaging.”
Lee JM, Abraham L, Lam DL, et al. Cumulative risk distribution for interval invasive second breast cancers after negative surveillance mammography[published online May 2, 2018]. doi: 10.1200/JCO.2017.76.8267