[Impact of SARS-CoV-2 immunization on a breast screening programme.]

A common secondary effect after SARS-CoV-2 immunization is an increased in size of the axillary lymph nodes ipsilateral to the vaccinated site. Eventually, an increased in size of the axillary lymph nodes may lead to a misinterpretation of the breast screening mammogram, performed in asymptomatic women between the age 50 to 69 years old for early breast cancer diagnosis. The aim of our research was to evaluate the impact of the vaccination for SARS-CoV-2 in the breast screening programmes in terms of recall rates and number of false positive results. As a secondary purpose we would analysed the protocols adopted by different breast screening units around the world after SARS-CoV-2 vaccination.

Observational and retrospective study analysing breast screening mammograms from a single Breast Cancer Screening Unit in Madrid. The mammograms of previously vaccinated women were analysed, reviewing the axillary lymph nodes and the re-call rate secondary to axillary lymphadenopathies.

Four hundred and twenty three screening mammograms were performed in May 2021 in the University Hospital Ramon y Cajal in Madrid, which is part of the Breast Screening Programme in Madrid, Spain. None of the women previously vaccinated for SARS-CoV-2 were recalled for complementary studies due to an increased in the axillary lymph nodes.

The protocol stablished by the Spanish Society of Breast Image that stands up for a routine breast screening mammogram after SARS-CoV-2 immunization, has no increase in the recall rate or increase in number of false positives.