Interval Breast Cancer Epidemiology, Radiology and Biological Characteristics

Abstract

When mammography screening programs are fully implemented, interval cancers comprise a substantial proportion of incident breast cancers. Interval cancers may have been overlooked at the last mammography examination or become apparent because they grew so rapidly that the detectable preclinical phase (sojourn time) was shorter than the screening interval. This overview describes the epidemiology, radiological and biological characteristics and time of diagnosis of interval breast cancers in population of mammography screening. Our team retrospectively collected data of symptomatic patients who presented to the West Hertfordshire Trust Breast Unit during the period from 1st of October 2016 until the 30th of September 2017 and identified any interval cancers (screening imaging 40 months prior). Imaging included two-view digital mammogram as well as ultrasound. The total number of cancers diagnosed during this period was 335 patients of which a total of 49 patients (14.6%) were interval cancers, with an average age of 62.42 years; 48 patients (97.9%) had new cancers while one patient (2.1%) had recurrent disease, and 2 patients (4%) had metastatic disease.

Average tumour size was 26.79 mm (range 81 mm); 37 patients (75. 5%) had IDC with or without other pathology while average tumour grade was grade 2. Our review demonstrated that interval cancers are more common with invasive high-grade disease; multicentre further studies including larger numbers will be very informative.