Bronchiolitis obliterans organizing pneumonitis primed by adjuvant radiotherapy in breast cancer patient in comparison with COVID-19 pneumonia: a case series

Abstract

radiotherapy (RT) is a milestone in breast cancer conserving treatment. The lung and heart are the main organs at risk to be considered when an external beam RT is planned regardless of the chosen modality (3D conformal or IMRT). Although many efforts to comply with organ at risk constraints and minimize dose to them are observed in planning, unexpected severe toxicities could occur like pneumonitis outside the radiation port due to Bronchiolitis Obliterans Organizing Pneumonitis (BOOP) primed by radiotherapy. Its clinical and radiological diagnosis do not meet criteria of a classical radiation pneumonitis but findings seem to be similar to COVID-19 (CO-19) pneumonia. At the COVID-19 pandemic time as at present, these clinical and CT findings similarities could yield confounding interpretations in diagnosis and lead to unnecessary panic induced scenarios with an admission of the suspected affected patient in isolation pathway. Moreover CO-19 pneumonia diagnosis may be complicated when negative swab and false negative Real-Time Polymerase Chain Reaction (RT-PCR) are recorded. Broncholavage fluid (BAL) and specific serology together to adequate anamnesis may help clinicians in making a correct diagnosis and report. Herein a case series of two case reports showing many overlapping features between RT-BOOP and CO-19 pneumonia in two patients with negative swab and RT-PCR CO-19 test.