PMID- 36306978 OWN - NLM STAT- MEDLINE DCOM- 20221220 LR - 20230208 IS - 1879-355X (Electronic) IS - 0360-3016 (Linking) VI - 115 IP - 1 DP - 2023 Jan 1 TI - Radiation-Induced Hypothyroidism in Patients With Breast Cancer After Hypofractionated Radiation Therapy: A Prospective Cohort Study. PG - 83-92 LID - S0360-3016(22)00557-0 [pii] LID - 10.1016/j.ijrobp.2022.04.052 [doi] AB - PURPOSE: Our objective was to assess the incidence and risk factors of radiation-induced hypothyroidism (RHT) after adjuvant hypofractionated radiation therapy (RT) in patients with breast cancer. METHODS AND MATERIALS: Eligible patients with breast cancer who were treated with hypofractionated RT were prospectively evaluated. Thyroid function tests were performed before and at regular times after RT. RHT was defined as twice elevated serum thyroid-stimulating hormone (TSH) with decreased or normal free thyroxin after RT. The patient, tumor, and treatment factors were evaluated for possible associations with the risk of RHT. RESULTS: Five hundred patients were analyzed. All patients underwent chest wall/breast with or without regional nodal irradiation. Among them, 369 (73.8%) patients received supraclavicular nodal radiation (SCRT). Eighty-two (16.4%) patients had elevated TSH before RT. At a median follow-up of 21.9 months, 131 (26.2%) patients developed RHT, and 59 (11.8%) patients received thyroid hormone-replacement therapy. Patients with SCRT had a significantly increased 2-year cumulative incidence of RHT compared with patients without SCRT (31.5% and 11.4%, P<.001). The peak incidence of RHT occurred around 6 to 12 months after RT. Multivariate analysis revealed that elevated baseline TSH and increased thyroid mean dose (Dmean) were independent risk factors for developing RHT. After adjusted for baseline TSH, there was a nonlinear relationship between thyroid Dmean and the risk of RHT. Dmean >21 Gy was the threshold value for predicting RHT (hazard ratio, 2.2; P<.001). CONCLUSIONS: The incidence of RHT was high in patients with breast cancer. Thyroid function test should be started no later than 6 months after RT. We recommend that the Dmean of the thyroid should be kept lower than 21 Gy for hypofractionated RT. CI - Copyright (c) 2022 Elsevier Inc. All rights reserved. FAU - Zhao, Xu-Ran AU - Zhao XR AD - Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China. FAU - Fang, Hui AU - Fang H AD - Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China. FAU - Jing, Hao AU - Jing H AD - Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China. FAU - Tang, Yu AU - Tang Y AD - Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China. FAU - Song, Yong-Wen AU - Song YW AD - Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China. FAU - Liu, Yue-Ping AU - Liu YP AD - Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China. FAU - Jin, Jing AU - Jin J AD - Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China. FAU - Chen, Bo AU - Chen B AD - Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China. FAU - Qi, Shu-Nan AU - Qi SN AD - Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China. FAU - Tang, Yuan AU - Tang Y AD - Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China. FAU - Lu, Ning-Ning AU - Lu NN AD - Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China. FAU - Li, Ning AU - Li N AD - Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China. FAU - Li, Ye-Xiong AU - Li YX AD - Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China. Electronic address: yexiong12@163.com. FAU - Wang, Shu-Lian AU - Wang SL AD - Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China. Electronic address: wangsl@cicams.ac.cn. LA - eng PT - Journal Article PT - Research Support, Non-U.S. Gov't DEP - 20221025 PL - United States TA - Int J Radiat Oncol Biol Phys JT - International journal of radiation oncology, biology, physics JID - 7603616 RN - 9002-71-5 (Thyrotropin) SB - IM MH - Humans MH - Female MH - *Breast Neoplasms/pathology MH - Prospective Studies MH - *Radiation Injuries/etiology MH - *Hypothyroidism/epidemiology/etiology MH - Thyrotropin EDAT- 2022/10/29 06:00 MHDA- 2022/12/21 06:00 CRDT- 2022/10/28 19:25 PHST- 2022/01/29 00:00 [received] PHST- 2022/04/04 00:00 [revised] PHST- 2022/04/07 00:00 [accepted] PHST- 2022/10/29 06:00 [pubmed] PHST- 2022/12/21 06:00 [medline] PHST- 2022/10/28 19:25 [entrez] AID - S0360-3016(22)00557-0 [pii] AID - 10.1016/j.ijrobp.2022.04.052 [doi] PST - ppublish SO - Int J Radiat Oncol Biol Phys. 2023 Jan 1;115(1):83-92. doi: 10.1016/j.ijrobp.2022.04.052. Epub 2022 Oct 25.