Low-Dose Whole-Lung Irradiation for COVID-19 Pneumonia: Final Results of a Pilot Study.

Introduction: Radiation therapy (RT), commonly used in cancer management, has been considered as one of the potential treatments for COVID-19 pneumonia. Here, we present the results of the pilot trial evaluating low-dose whole-lung irradiation (LD-WLI) in patients with COVID-19 pneumonia.

Methods: Ten patients with moderate COVID-19 pneumonia were treated with LD-WLI in a single fraction of 0.5 or 1.0 Gy along with the national protocol. The primary endpoint was an improvement in Spo. The secondary endpoints were the number of days of hospital/intensive care unit stay, the number of intubations after RT, 28-day mortality, and changes in biomarkers. The response rate (RR) was defined as an increase in Spo upon RT with a rising or constant trend in the next 2 days, clinical recovery (CR) including patients who were discharged or acquired Spo ≥93% on room air, and 28-day mortality rate defined based on days of RT.

Results: The median age was 75 years (80% male). Five, 1, and 4 patients received single-dose 0.5 Gy, two-dose 0.5 Gy, and single-dose 1.0 Gy LD-WLI, respectively. The mean improvement in Spo at days 1 and 2 after RT was 2.4% (±4.8%) and 3.6% (±6.1%), respectively, with improvement in 9 patients after 1 day. Five, 1, and 4 patients were discharged, opted out of the trial, and died in the hospital, respectively. Two of 5 discharged patients died within 3 days at home. Among discharged patients, the Spo at discharge was 81% to 88% in 3 patients and 93% in the other 2 patients. Overall, the RR and CR were 63.6% and 55.5%, respectively. The RR, CR, and 28-day mortality of the single 0.5 Gy and 1.0 Gy WLI groups were 71.4% versus 50% (P = .57), 60% versus 50% (P = .64), and 50% versus 75% (P = .57), respectively.

Conclusion: LD-WLI with a single fraction of 0.5 Gy or 1 Gy is feasible. A randomized trial with patients who do not receive radiation is required to assess the efficacy of LD-WLI for COVID-19.