Successful treatment with steroid pulse therapy for a COVID-19 case with progressive respiratory failure during treatment for pleural metastasis of breast cancer

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infected patients are at high risk for developing severe conditions if other comorbidities are present, such as advanced cancer. Although the regulation of immune response is thought to play an important role in the treatment of coronavirus disease 2019 (COVID-19), physicians often have difficulties in selecting the most appropriate treatment. Furthermore, the impact that interrupting breast cancer treatment due to a COVID-19 infection has on patient outcomes is still unknown. Herein we report a case of advanced breast cancer in a patient whose COVID-19 acute respiratory failure was successfully treated with minimal interruption to their anticancer therapy for recurrent breast cancer. CASE PRESENTATION: A 48-year-old woman developed carcinomatous pleurisy after curative surgery for breast cancer. One month after the initiation of targeted therapy with palbociclib and fulvestrant, the pleural effusion decreased, but soon after she developed a COVID-19 infection. Dexamethasone (8 mg/day) was administered due to a prolonged fever, but her respiratory symptoms got worse and pneumonia appeared on a computed tomography (CT) scan 7 days after hospitalization. Thus, steroid pulse therapy (methylprednisolone 1000 mg/day) was administered for 3 days. Her respiratory condition rapidly improved. Two weeks after hospital discharge, complete regression of pneumonia was confirmed on CT scan, and her targeted therapy was resumed at the same dose and strength. More than 6 months later, her metastatic disease remains stable while on the same treatment. Retrospective analysis of the patient's neutralizing antibodies found the neutralizing activity was low in the early stages of infection, but became high after recovery. This suggests the patient acquired an immunity to SARS-CoV-2 through the infection, despite having a mild myelosuppression due to treatment for recurrent breast cancer. CONCLUSIONS: Steroid pulse therapy is available worldwide, and may have an important role in cancer patients who develop severe pneumonia from SARS-CoV-2, by enabling them to avoid any long-term disruption to anticancer therapy. Moreover, it might also be useful when antiviral therapies lose their efficacy due to mutations of the virus, such as the Omicron variant. A critical element in cases such as this one is that treatment decisions are made by a team of specialists, including pulmonologists.