Identification of Predictive Factors Causing 'Atrial Fibrillation' as a Side Effect of Radiation Therapy for Lung Cancer

Effect of Radiation Dose on Sinoatrial Node
Atrial Fibrillation Induction and Survival
Higher Dose Increases Atrial Fibrillation Incidence 15-Fold

[Asia Economy Reporter Lee Gwan-joo] A domestic research team has identified a predictive factor that increases the risk of 'atrial fibrillation,' a representative side effect occurring during chemoradiation therapy for lung cancer patients, which affects survival rates.

The research team led by Professors Yoon Hong-in and Kim Kyung-hwan from the Department of Radiation Oncology at Yonsei Cancer Hospital, along with Professors Kang Seok-min and Oh Jae-won from the Department of Cardiology at Severance Cardiovascular Hospital, announced on the 27th that when the radiation dose delivered to the sinoatrial node located in the right atrium during radiation therapy for lung cancer patients is high, the risk of atrial fibrillation increases by about 15 times.

Chemoradiation therapy is a treatment method that delivers a large amount of radiation to the cancer site to reduce or eliminate tumors, but side effects can occur in the areas exposed to radiation. In the case of lung cancer, coronary artery disease and heart failure can be induced in the heart exposed to radiation during treatment, and research on this has been actively conducted recently. However, studies on atrial fibrillation, which is the most frequently observed among these, have not been conducted until now.

The research team analyzed the frequency of atrial fibrillation by measuring the radiation dose to the sinoatrial node on CT scans of 560 patients, including 321 non-small cell lung cancer patients and 239 small cell lung cancer patients who received concurrent chemoradiation therapy at Yonsei Cancer Hospital from 2008 to 2019. As a result, patients who received a high radiation dose to the sinoatrial node had about 15 times higher risk of developing atrial fibrillation compared to those who received a low dose.

In the small cell lung cancer cohort, the incidence of atrial fibrillation was 25% in patients with a high dose to the sinoatrial node, which was higher compared to 2.7% in the low-dose group. Similarly, in the non-small cell lung cancer cohort, the incidence of atrial fibrillation was 9.9% in the high-dose group, higher than 0.7% in the low-dose group.

Specifically, in the small cell lung cancer cohort, 25% of patients who received a radiation dose of 53.5 Gy or more to the sinoatrial node developed atrial fibrillation, whereas only 2.7% of patients in the low-dose group developed it. In non-small cell lung cancer, 9.9% of patients with a radiation dose of 20.0 Gy or more to the sinoatrial node developed atrial fibrillation, compared to 0.7% in the low-dose group. Notably, patients with a high radiation dose to the sinoatrial node showed about a 20% decrease in 3-year survival rates. Other cardiac side effects were not related to the radiation dose to the sinoatrial node.

Professor Kang said, "This is an important research achievement that identified atrial fibrillation, a risk factor for heart failure, as being related to the radiation dose to the sinoatrial node." Professor Yoon added, "We have created evidence for the dose limit to the sinoatrial node that can be reflected in radiation therapy guidelines," and said, "The carbon ion therapy, which Yonsei Medical Center will start next year as the first in Korea, is expected to reduce the dose to surrounding normal organs and minimize side effects in normal tissues of lung cancer patients."

This study was published in the latest issue of the Journal of the American Medical Association Oncology (JAMA Oncology, IF 33.016).

This content was produced with the assistance of AI translation services.