Abstract P3-19-28: The impact of PM2.5 on the radiation-induced pneumonitis in patients with breast cancer

Abstract

Abstract Purpose: Exposure to particulate matter (PM) air pollution has been associated with adverse effect on respiratory disease, but no study has investigated its impact on radiation-induced pneumonitis (RIP) in patients with breast cancer who received adjuvant radiation therapy (RT). Materials and Methods: We conducted a retrospective review of 2,762 breast cancer patients who received postoperative RT between 2017 and 2020 in a single institution. Particulate matter data including PM2.5 and PM10 were retrieved from the open dataset in the ‘Gyeonggi Data Dream’. We used the average, median and maximum values of the PM2.5 and PM10 measured during daytime when a patient visited to the hospital for RT. We excluded the patients when missing PM data exceeded 50% of the total treatment period (N=26). Finally, altogether 2,736 patients were analyzed. Results: Overall incidence rate of RIP was 1.74%. There were no significant differences in average value of PM2.5 and number of RT fractions between RIP (+) and RIP (-) groups, but marginal differences were found in RT techniques (3-dimentional conformal RT vs. intensity modulated RT, P=0.053) and proportion of PM2.5 value ≥ 35 (μg/m3) (P=0.053) between the two groups. After adjusting for age, RT technique, regional irradiation, fractionation and boost, the average value of PM2.5 was significantly associated with a higher risk of RIP (Odds ratio [OR] 1.05, 95% confidential incidence [CI] 1.00-1.10, P=0.047) when patients received ≥ 20 fractions of RT. Especially, PM2.5 ≥ 35 (μg/m3) showed significant higher risk of RIP (OR 4.32, 95% CI 1.34-13.87, P=0.014) in patients with ≥ 20 fractions of RT after adjustment of aforementioned covariates. Other PM data (median, maximum value of PM2.5 and all PM10 values) were not related to the RIP regardless of the number of RT fractions. Conclusion: This is the first study to reveal the association between PM2.5 and RIP in breast cancer patients who received 20 fractions or more of postoperative RT. Citation Format: Dong-Yun Kim, In Ah Kim, Bum-Sup Jang. The impact of PM2.5 on the radiation-induced pneumonitis in patients with breast cancer [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P3-19-28.