방사선의학 웹진

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Abstract
Background/aim: Exposure to particulate matter (PM) air pollution is known to adversely affect respiratory disease, but no study has examined its effect on radiation-induced pneumonitis (RIP) in patients with breast cancer.

Patients and methods: We conducted a retrospective review of 2,736 patients with breast cancer who received postoperative radiation therapy (RT) between 2017 and 2020 in a single institution. The distance between the PM measurement station and our institution was only 3.43 km. PM data, including PM2.5 and PM10, were retrieved from the open dataset in the official government database.

Results: Overall incidence rate of RIP was 1.74%. 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 (p=0.047) when patients received ≥20 fractions of RT. Specifically, PM2.5 ≥35 (μg/m3) showed a significantly higher risk of RIP (p=0.019) in patients with ≥20 fractions of RT.

Conclusion: This is the first study to reveal the association between PM2.5 and RIP in patients with breast cancer who received 20 fractions or more of postoperative RT. We demonstrated that high PM2.5 levels around the RT institution were associated with RIP, suggesting that reducing PM air pollution may be a modifiable risk factor.

Figure: Analyses of the relationship between particulate matter (PM) data [overall average PM2.5 values (A) and PM2.5 values ≥35 (B)] and radiation-induced pneumonitis, stratifying the number of radiation therapy (RT) fractions. Significantly increased odds ratio (OR) over 20 fractions of RT for both overall average PM2.5 values and PM2.5 values ≥35 was found.

Table. Prognostic factors for incidence of RIP in patients with ≥ 20 fractions of RT

Affiliations

Dong-Yun Kim 1 2, In Ah Kim 1 3, Bum-Sup Jang 4 5
1Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Republic of Korea.
2Department of Radiation Oncology, Chung-Ang University Hospital, Seoul, Republic of Korea.
3Department of Radiation Oncology, Seoul National University Bundang Hospital, Seongnam, Republic of Korea.
4Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Republic of Korea; bigwiz83@snu.ac.kr.
5Department of Radiation Oncology, Seoul National University Hospital, Seoul, Republic of Korea.