Importance: Atrial fibrillation (AF) can develop following thoracic irradiation. However, the critical cardiac substructure responsible for AF has not been properly studied. Objective: To describe the incidence of AF in patients with lung cancer and determine predictive cardiac dosimetric parameters. Design, Setting, and Participants: This retrospective cohort study was performed at a single referral center and included 239 patients diagnosed with limited-stage small cell lung cancer (SCLC) and 321 patients diagnosed with locally advanced non-small cell lung cancer (NSCLC) between August 2008 and December 2019 who were treated with definitive chemoradiotherapy. Exposures: Radiation dose exposure to cardiac substructures, including the chambers, coronary arteries, and cardiac conduction nodes, were calculated for each patient. Main Outcomes and Measures: Main outcomes were AF and overall survival. Results: Of the 239 and 321 patients with SCLC and NSCLC, the median (IQR) age was 68 (60-73) years and 67 (61-75) years, and 207 (86.6%) and 261 (81.3%) were men, respectively. At a median (IQR) follow-up time of 32.7 (22.1-56.6) months, 9 and 17 patients experienced new-onset AF in the SCLC and NSCLC cohorts, respectively. The maximum dose delivered to the sinoatrial node (SAN Dmax) exhibited the highest predictive value for prediction of AF. A higher SAN Dmaxsignificantly predicted an increased risk of AF in patients with SCLC (adjusted hazard ratio [aHR], 14.91; 95% CI, 4.00-55.56; P <.001) and NSCLC (aHR, 15.67; 95% CI, 2.08-118.20; P =.008). However, SAN Dmaxwas not associated with non-AF cardiac events. Increased SAN Dmaxwas significantly associated with poor overall survival in patients with SCLC (aHR, 2.68; 95% CI, 1.53-4.71; P <.001) and NSCLC (aHR, 1.97; 95% CI, 1.45-2.68; P <.001). Conclusions and Relevance: In this cohort study, results suggest that incidental irradiation of the SAN during chemoradiotherapy may be associated with the development of AF and increased mortality. This supports the need to minimize radiation dose exposure to the SAN during radiotherapy planning and to consider close follow-up for the early detection of AF in patients receiving thoracic irradiation.
|Number of pages||11|
|Publication status||Published - 2022 Nov 17|
Bibliographical noteFunding Information:
Funding/Support: This work was supported by the Severance Hospital Research fund for Clinical excellence (SHRC) (grant number C-2020-0040) to Dr Yoon); National Research Foundation of Korea (NRF) (grant numbers NRF-2021R1I1A1A01060135 [to Dr Oh] and NRF-2019R1C1C1009359 [to Dr Chang]); and Korea Food Research Institute funded by the Ministry of Science, ICT & Future Planning (grant number E0210400-01 [to Dr Choi]).
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All Science Journal Classification (ASJC) codes
- Cancer Research