Cumulative Risk Distribution for Interval Invasive Second Breast Cancers After Negative Surveillance Mammography.

The aim of the current study was to characterize the risk of interval invasive second breast cancers within 5 years of primary breast cancer treatment. We examined 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 from 1996 to 2012 in the Breast Cancer Surveillance Consortium. Interval invasive breast cancer was defined as ipsilateral or contralateral cancer diagnosed within 1 year after a negative surveillance mammogram. Discrete-time survival models—adjusted for all covariates—were used to estimate the probability of interval invasive cancer, given the risk factors for each surveillance round, and aggregated across rounds to estimate the 5-year cumulative probability of interval invasive cancer.