COVID-19 risk in breast cancer patients receiving CDK4/6 inhibitors: literature data and a monocentric experience.

Substantial changes in the management of cancer patients have been required worldwide in response to the COVID-19 pandemic. Beyond the due details on the primitive cancer site and setting at diagnosis, these latter adaptions are most commonly exemplified by a significant reduction in the screening of asymptomatic subjects, delays in elective surgery and radiotherapy for primary tumors, and dose reductions and/or delays in systemic therapy administration. Advanced breast cancer patients with hormonal receptor positive, HER2 negative tumors are usually treated with endocrine therapy combined with CDK 4/6 inhibitors as first- and second-line treatment. During the pandemic, experts' recommendations have suggested the omission or delay of CDK 4/6 inhibitors delivery, or a careful evaluation of their real need due to the hypothesized increased risk of SARS-Cov-2 infection and disease possibly related to neutropenia. The inherent literature is sparse and inconsistent. We herein present data on the use of CDK 4/6 inhibitors during the pandemic. The evidence reported punctually reflects the experience matured at our Institution, a comprehensive cancer centre, on the topic of interest.