2023 World Conference on Lung Cancer (Posters)-EP08.04. Evaluating Safety Profiles of Radiation-Related Toxicities in Thoracic Re-Irradiation

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This study evaluated the safety profiles of radiation-related toxicities in thoracic re-irradiation. The researchers retrospectively analyzed 70 patients with thoracic malignancies who underwent re-irradiation between 2019 and 2022. Different radiation techniques were used, including 3-dimensional conformal radiotherapy, stereotactic body radiotherapy, intensity-modulated radiotherapy, and passive-scatter proton therapy. Dosimetric parameters were reviewed from the first and re-irradiation treatments. The toxicities evaluated included radiation pneumonitis, heart, esophageal, and tracheal toxicities.<br /><br />The majority of patients had non-small cell lung cancer, with a median follow-up time of 35 months and a median survival of 27 months. The mean time between the first and re-irradiation treatments was 20.5 months. The researchers found that the lung V20 and mean lung dose were lower in the re-irradiation treatment compared to the first treatment. When evaluating the average dose composite parameters, they found a lung V20 of 25%, a heart maximum dose of 57.02Gy, and a tracheal maximum dose of 51.74Gy. No grade 3 or higher heart, tracheal, or esophageal toxicities were observed, and only one grade 5 toxicity was reported.<br /><br />Regarding radiation pneumonitis (RP), 18 patients had grade 3 RP requiring intervention, with most cases occurring after the re-irradiation treatment. Only half of the patients with a dose parameter of composite lung V20 35% developed grade 3 RP. A significant number of patients developed late RP between 12 to 24 months after re-irradiation. No statistical significance was found in the association between RP risk and dose parameters.<br /><br />In conclusion, the study found that thoracic re-irradiation is generally safe without grade 5 toxicities. However, careful follow-up is recommended for managing late RP symptoms. The researchers suggest that strict lung V20 35% is important in reducing the risk of RP, but further studies are needed to identify other lung radiation dose parameters. Attention should also be given to avoiding high-grade toxicities in the re-irradiation setting.

Asset Subtitle

Rohan Patel

Meta Tag

Speaker Rohan Patel

Topic Local-Regional NSCLC: Toxicities of Multimodality Therapy

Keywords

radiation-related toxicities

thoracic re-irradiation

safety profiles

dosimetric parameters

radiation techniques

non-small cell lung cancer

median follow-up time

average dose composite parameters

grade 3 RP

late RP symptoms