Introduction Radiotherapy (RT) -commonly employed 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 the improvement in SpO 2 . The secondary endpoints were the number of hospital/ICU stay days, the number of intubations after RT, 28-day mortality, and changes in biomarkers. The response rate (RR) was defined as a rise in SpO 2 upon RT with a rising or constant trend in the next 2 days, clinical recovery (CR) included patients who were discharged or acquired SpO 2 ≥93% on room air, and 28-day mortality rate was defined based on RT day. Results The median age was 75 years (80% male). Five, 1, and 4 patients received single 0.5Gy, two 0.5Gy, and single 1.0Gy LD-WLI, respectively. The mean improvement in SpO 2 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 the trial, and died in hospital, respectively. Two of 5 discharged patients died within 3 days at home. Among discharged patients, the SpO 2 at discharge was 81-88% in 3 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 single 0.5Gy- and 1.0Gy-WLI were 71.4 vs. 50% ( p = 0.57), 60 vs. 50% ( p = 0.64), and 50 vs. 75% ( p = 0.57), respectively. Conclusion LD-WLI with a single 0.5 Gy or 1 Gy-fraction is feasible. A randomized trial with patients that do not receive radiation is required to assess efficacy of LD-WLI for COVID-19.

Purpose: Novel coronavirus disease (COVID-19) is the current global concern. Radiotherapy (RT), commonly employed in cancer management, has been considered one of the potential treatments for COVID-19 pneumonia. Here, we present the final report of the pilot trial evaluating the efficacy and safety of low-dose whole-lung irradiation (LD-WLI) in patients with COVID-19 pneumonia. Methods and Materials: We enrolled patients with moderate COVID-19 pneumonia who were older than 60 years. Participants were treated with LD-WLI in a single fraction of 0.5 or 1.0Gy along with the national protocol of COVID-19. The primary endpoints were improvement of SpO2, the number of hospital/ICU stay days, and the number of intubations after RT and the secondary endpoints were alterations of the c-reactive peptide, interleukin-6, ferritin, procalcitonin, and D-dimer. The response rate (RR) was defined as a rise in SpO2 upon RT with rising or constant trend in the next two days, and clinical recovery (CR) included patients who were discharged from the hospital or acquired SpO2 ≥93% on room air. Results: Between 21 May 2020 and 2 July 2020, ten patients were enrolled. The median age was 75 years, 80% were male, and 80% had comorbidities. The first five patients received a single 0.5Gy-WLI, and others received 1.0Gy. Patients were followed for 2-14 days (median 5.5 days). Following one day, nine patients experienced an improvement in SpO2. Five patients were discharged (median 6th day, range 2nd-14th day), and four patients died (median 7th day, range 3rd-10th day). Overall, the RR and CR were 60.0% and 55.5%, respectively. The RR and CR rates of 0.5- and 1.0Gy group were 80% vs 40% and 75% vs 40%, respectively. No acute radiation-induced toxicity was recorded. Conclusions: LD-WLI with a single 0.5Gy fraction seems to be a more appropriate dose to warrant further evaluation in a large-scale, randomized trial.

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