Clinical Research Directory

Inclusion Criteria: 1. patients with pathologically or cytologically confirmed primary breast cancer, 2. aged 18 years or older but younger than 80 years, 3. with complete and reliable medical records, 4. for those with COVID-19 infection, documented evidence of a positive test result. Exclusion Criteria: 1. concomitant pulmonary malignancies, 2. a history of prior thoracic radiotherapy, 3. concurrent pulmonary infections other than COVID-19 during radiotherapy, 4. missing key data with loss to follow-up, 5. or any other condition considered unsuitable for enrollment by the investigators.