Effects of delayed callback from screening mammography due to the COVID-19 pandemic

To determine the frequency and distinguishing imaging characteristics of breast cancers detected on screening mammography which was initially evaluated as a probably benign lesion and the workup was delayed due to the COVID-19 pandemic.

REB-approved multicenter retrospective screening mammography studies and patient's chart review carried out between February 2020 and March 2020. According to an institutional decision, the frequency and imaging findings deemed probably benign on screening mammography after review by a breast fellowship-trained radiologist with workup deferred until after the first pandemic wave plateau in late July 2020 were recorded. Results were correlated with histopathology if tissue sample performed or an uneventful 2 years follow-up. Descriptive statistical analysis was used to describe the retrieved data set.

Out of 1816 mammography screening between February 2020 and March 2020, 99 women, median age 58 years (range 35-84), 99 mammography had possibly benign findings with workup delayed, and two patients, age 49 and 56, had cancers (2.02%), misinterpreted as benign findings. Both malignant cases were focal asymmetries, with pathology of invasive ductal carcinoma, 12 mm and 9 mm in size. No in-situ carcinoma was detected.

The low rate of cancer detected suggests that a delay callback may be a reasonable option for some likely benign findings when immediate callback is not an option, such as during a pandemic. Larger studies would be helpful to support our findings and may allow us to translate the adoption of such a model during potential future pandemic.

The results of this study may be helpful for a future situation when delaying a call back from screening mammography is again required.