Abstract 153P
Background
The incidence of radiation pneumonia after chemoradiotherapy was evaluated in patients with non-small cell lung cancer (NSCLC) with a history of the Covid-19 disease.
Methods
Group I included 33 patients who had COVID-19 disease but no imaging findings were in the radiological examination and 6-15 months later were diagnosed with stage III Non-small cell lung cancer (NSCLC). Group II consisted of 56 patients with stage III NSCLC, who had not infected with Covid-19 disease before. In these groups, the incidence of radiation pneumonia was evaluated after concurrent chemoradiotherapy. The total dose of radiation to the primary tumor in the lungs and pathological lymph nodes was 60-66 Gy (2.0 Gy per fraction x 5 times a week). All patients underwent 4-5 cycles of concurrent chemotherapy with carboplatin 2 AUC + paclitaxel 45mg/m2 scheme. Intensity modulated radiation therapy was planned for all patients with lung dose V20<30Gy, mean lung dose (MLD)<20 Gy (Quantitative Analysis of Normal Tissue Effects in the Clinic -QUANTEC) in the dose-volume histogram.
Results
According to the QUANTEC, the risk of symptomatic radiation pneumonia is seen in 20% of cases when lung V20Gy<30%, MLD<20. During the observation period 6-18 months after radiotherapy, in group I, symptomatic radiation pneumonia was 53% (41% Grade II, 12% Grade III), but in group II symptomatic pneumonia was 27% (22% grade II, 5% grade III respectively). As a result of the symptomatic treatment, the symptoms of radiation pneumonia were eliminated.
Conclusions
The incidence of pneumonia after radiotherapy is high in patients with a history of COVID-19 disease, who though didn't have lung damage in the radiological examination. This can be explained by subclinical damage of capillaries in the lung tissue, hypoxia, and weakening of reparation of post-radiation damage as a result of COVID-19 disease. In this group of patients, it is appropriate to reduce the target radiation volume and total dose in the lungs and perform radiotherapy with motion management.
Legal entity responsible for the study
National Center of Oncology, Radiation Oncology Department.
Funding
Has not received any funding.
Disclosure
The author has declared no conflicts of interest.