title: Dosimetric analysis of the brachial plexus among patients with breast cancer treated with post-mastectomy radiotherapy to the ipsilateral supraclavicular area: report of 3 cases of radiation-induced brachial plexus neuropathy.
abstract: BACKGROUND
  The purpose of this study was to evaluate the brachial plexus (BP) dose of postmastectomy radiotherapy (PMRT) to the ipsilateral supraclavicular (ISCL) area, and report the characteristics of radiation-induced brachial plexus neuropathy (RIBPN).
  
  
  METHODS
  The BP dose of 31 patients who received adjuvant PMRT to the ISCL area and chest wall using three-dimensional conformal radiotherapy (3DCRT) and the records of 3 patients with RIBPN were retrospectively analyzed based on the standardized Radiation Therapy Oncology Group-endorsed guidelines. The total dose to the ISCL area and chest wall was 50 Gy in 25 fractions.
  
  
  RESULTS
  Patients with a higher number of removed lymph nodes (RLNs) had a higher risk of RIBPN (hazard ratio [HR]: 1.189, 95% confidence interval [CI]: 1.005-1.406, p = 0.044). In 31 patients treated with 3DCRT, the mean dose to the BP without irradiation to the ISCL area was significantly less than that with irradiation to the ISCL area (0.97 ± 0.20 vs. 44.39 ± 4.13 Gy, t = 136.75, p <0.001). In the 3DCRT plans with irradiation to the ISCL area and chest wall, the maximum dose to the BP was negatively correlated with age (r = -0.40, p = 0.026), body mass index (BMI) (r = -0.44, p = 0.014), and body weight (r = -0.45, p = 0.011). Symptoms of the 3 patients with RIBPN occurred 37-65 months after radiotherapy, and included progressive upper extremity numbness, pain, and motor disturbance. After treatment, 1 patient was stable, and the other 2 patients' symptoms worsened.
  
  
  CONCLUSIONS
  The incidence of RIBPN was higher in patients with a higher number of RLNs after PMRT. The dose to the BP is primarily from irradiation of the ISCL area, and is higher in slim and young patients. Prevention should be the main focus of managing RIBPN, and the BP should be considered an organ-at-risk when designing a radiotherapy plan for the ISCL area.
authors.affiliation: Department of Radiation Oncology, Xiamen Cancer Center, the First Affiliated Hospital of Xiamen University, Xiamen, 361003, People's Republic of China. unowu12345@hotmail.com.
authors.forename: San-Gang
authors.initials: SG
authors.lastname: Wu
authors.affiliation: Department of Radiation Oncology, Collaborative Innovation Center of Cancer Medicine, State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou, 510060, People's Republic of China. huangsj@sysucc.org.cn.
authors.forename: Si-Juan
authors.initials: SJ
authors.lastname: Huang
authors.affiliation: Department of Obstetrics and Gynecology, Xiamen Cancer Center, the First Affiliated Hospital of Xiamen University, Xiamen, 361003, People's Republic of China. juanzhou12345@hotmail.com.
authors.forename: Juan
authors.initials: J
authors.lastname: Zhou
authors.affiliation: Department of Radiation Oncology, Collaborative Innovation Center of Cancer Medicine, State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou, 510060, People's Republic of China. sunjy@sysucc.org.cn.
authors.forename: Jia-Yuan
authors.initials: JY
authors.lastname: Sun
authors.affiliation: Department of Basic Medical Science, Medical College, Xiamen University, Xiamen, 361003, People's Republic of China. guohanxm@163.com.
authors.forename: Han
authors.initials: H
authors.lastname: Guo
authors.affiliation: Department of Radiation Oncology, Collaborative Innovation Center of Cancer Medicine, State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou, 510060, People's Republic of China. lify@sysucc.org.cn.
authors.forename: Feng-Yan
authors.initials: FY
authors.lastname: Li
authors.affiliation: Department of Radiation Oncology, Xiamen Cancer Center, the First Affiliated Hospital of Xiamen University, Xiamen, 361003, People's Republic of China. linqinxmfh@126.com.
authors.forename: Qin
authors.initials: Q
authors.lastname: Lin
authors.affiliation: Department of Radiation Oncology, Collaborative Innovation Center of Cancer Medicine, State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou, 510060, People's Republic of China. linhx@sysucc.org.cn.
authors.forename: Huan-Xin
authors.initials: HX
authors.lastname: Lin
authors.affiliation: Department of Radiation Oncology, Collaborative Innovation Center of Cancer Medicine, State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou, 510060, People's Republic of China. hezhy@sysucc.org.cn.
authors.forename: Zhen-Yu
authors.initials: ZY
authors.lastname: He
mesh_terms: D000328:Adult; D001917:Brachial Plexus / Q000528:radiation effects*; D020516:Brachial Plexus Neuropathies; D001943:Breast Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D005260:Female; D006801:Humans; D015994:Incidence; D008197:Lymph Node Excision; D008408:Mastectomy; D008875:Middle Aged; D058958:Organs at Risk / Q000528:radiation effects; D011832:Radiation Injuries; D011874:Radiometry; D018714:Radiotherapy, Adjuvant / Q000009:adverse effects*; D020266:Radiotherapy, Conformal / Q000009:adverse effects / Q000379:methods; D012189:Retrospective Studies; D012307:Risk Factors