Introduction: The present analysis aims to evaluate the consequences of a 2-month interruption of mammographic
screening on breast cancer (BC) stage at diagnosis and upfront treatments in a region of Northern Italy highly
affected by the severe acute respiratory syndrome-related coronavirus-2 (SARS-CoV-2) virus.
Methods: This retrospective single-institution analysis compared the clinical pathological characteristics of BC
diagnosed between May 2020 and July 2020, after a 2-month screening interruption, with BC diagnosed in the
same trimester of 2019 when mammographic screening was regularly carried out.
Results: The 2-month stop in mammographic screening produced a signiﬁcant decrease in in situ BC diagnosis ( ! 10.4%)
and an increase in node-positive ( þ 11.2%) and stage III BC ( þ 10.3%). A major impact was on the subgroup of patients
with BC at high proliferation rates. Among these, the rate of node-positive BC increased by 18.5% and stage III by
11.4%. In the subgroup of patients with low proliferation rates, a 9.3% increase in stage III tumors was observed,
although node-positive tumors remained stable. Despite screening interruption, procedures to establish a deﬁnitive
diagnosis and treatment start were subsequently carried out without delay.
Conclusion: Our data showed an increase in node-positive and stage III BC after a 2-month stop in BC screening. These
ﬁndings support recommendations for a quick restoration of BC screening at full capacity, with adequate prioritization
strategies to mitigate harm and meet infection prevention requirements.
Key words: COVID-19, breast cancer, stage at diagnosis, mammographic screening
The T-cell Lymphoma Project is an international registry prospective study that enrolled patients with newly