Outcomes of Patients With Breast Cancer Treated With or Without Internal Mammary Irradiation: A Single-Center, Retrospective Propensity Score–Matched Study
Issued Date
2023-01-01
Resource Type
eISSN
24521094
Scopus ID
2-s2.0-85140219230
Journal Title
Advances in Radiation Oncology
Volume
8
Issue
1
Rights Holder(s)
SCOPUS
Bibliographic Citation
Advances in Radiation Oncology Vol.8 No.1 (2023)
Suggested Citation
Jitwatcharakomol T., Setakoranukul J., Ithimakin S., Krittayaphong R., Thephamongkhol K. Outcomes of Patients With Breast Cancer Treated With or Without Internal Mammary Irradiation: A Single-Center, Retrospective Propensity Score–Matched Study. Advances in Radiation Oncology Vol.8 No.1 (2023). doi:10.1016/j.adro.2022.101072 Retrieved from: https://repository.li.mahidol.ac.th/handle/20.500.14594/82641
Title
Outcomes of Patients With Breast Cancer Treated With or Without Internal Mammary Irradiation: A Single-Center, Retrospective Propensity Score–Matched Study
Author's Affiliation
Other Contributor(s)
Abstract
Purpose: Internal mammary lymph node radiation therapy (IMN-RT) has unclear benefits. Historical data were based on only conventional (2-dimensional) radiation techniques. In this 3-dimensional radiation therapy era, we compared the distant metastasis–free survival (DMFS) rates of patients receiving IMN-RT with those who did not include coverage of the IMN (non–IMN-RT). This study aimed to determine the relationship between IMN-RT and distant metastasis control in patients with lymph node–positive breast cancer. Methods and Materials: This was a single-center retrospective cohort study. Patients were divided into 2 groups: IMN-RT and non–IMN-RT. The criterion of the IMN-RT group was that 80% of the prescribed dose covered ≥98% of the Clinical Target Volume of IMN. The primary outcome was 4-year DMFS, and the secondary outcomes were 4-year overall survival, 4-year disease-free survival, and cardiac toxicity. Results: From January 2012 to December 2018, 570 patients were evaluated (IMN-RT, 143 patients; non–IMN-RT, 427 patients). Propensity score matching decreased the number of patients in each group to 139. The median follow-up was 4.3 years. The 4-year DMFS rates were as follows: IMN-RT, 79.1% (95% confidence interval [CI], 70.1%-85.6%), and non–IMN-RT, 82.8% (95% CI, 74.2%-88.7%; P =.43). The groups’ 4-year overall survival and disease-free survival rates did not differ. The 4-year overall survival rates were 84.3% (95% CI, 76.4%-89.8%) for IMN-RT and 88.1% (95% CI, 81.0%-92.7%; P =.39) for non–IMN-RT. The 4-year disease-free survival rates were 77.1% (95% CI, 68.1%-83.8%) for IMN-RT and 82.1% (95% CI, 73.6%-88.1%; P =.29) for non–IMN-RT. There was no significant difference in cardiac toxicity (IMN-RT, 1.4%; non–IMN-RT, 1.4%; P = 1.0). Conclusions: In the modern radiation technique era with real-world data, we could not find a benefit of internal mammary irradiation.