title: The Evolution of and Risk Factors for Neck Muscle Atrophy and Weakness in Nasopharyngeal Carcinoma Treated With Intensity-Modulated Radiotherapy: A Retrospective Study in an Endemic Area.
abstract: The aim of this study was to investigate the evolution of sternocleidomastoid muscle (SCM) atrophy in nasopharyngeal carcinoma (NPC) patients following intensity-modulated radiotherapy (IMRT), and the relationship between SCM atrophy and neck weakness.Data were retrospectively analyzed from 223 biopsy-proven NPC patients with no distant metastasis who underwent IMRT with or without chemotherapy. The volume of SCM was measured on pretreatment magnetic resonance imaging (MRI), and MRIs were conducted 1, 2, and 3 years after the completion of IMRT. Change in SCM volume was calculated and classified using the late effects of normal tissues-subjective, objective, management, and analytic system. The grade of neck muscle weakness, classified by the Common Terminology Criteria for Adverse Events V 3.0, was measured 3 years after the completion of IMRT.The average SCM atrophy ratio was -10.97%, -18.65%, and -22.25% at 1, 2, and 3 years postirradiation, respectively. Multivariate analysis indicated N stage and the length of time after IMRT were independent prognostic variables. There were significant associations between the degree of SCM atrophy and neck weakness.Radical IMRT can cause significant SCM atrophy in NPC patients. A more advanced N stage was associated with more severe SCM atrophy, but no difference was observed between N2 and N3. SCM atrophy progresses over time during the 3 years following IMRT. Grade of SCM atrophy is significantly associated with neck weakness.
authors.affiliation: From the Department of Radiation Oncology (L-LZ, Y-PM, G-QZ, L-LT, Z-YQ, LL, J-JY, JM, YS), State Key Laboratory of Oncology in Southern China, Cancer Center, Sun Yat-sen University; and Department of Medical Statistics and Epidemiology (A-HL), School of Public Health, Sun Yat-sen University, Guangzhou, People's Republic of China.
authors.forename: Lu-Lu
authors.initials: LL
authors.lastname: Zhang
authors.forename: Yan-Ping
authors.initials: YP
authors.lastname: Mao
authors.forename: Guan-Qun
authors.initials: GQ
authors.lastname: Zhou
authors.forename: Ling-Long
authors.initials: LL
authors.lastname: Tang
authors.forename: Zhen-Yu
authors.initials: ZY
authors.lastname: Qi
authors.forename: Li
authors.initials: L
authors.lastname: Lin
authors.forename: Ji-Jin
authors.initials: JJ
authors.lastname: Yao
authors.forename: Jun
authors.initials: J
authors.lastname: Ma
authors.forename: Ai-Hua
authors.initials: AH
authors.lastname: Lin
authors.forename: Ying
authors.initials: Y
authors.lastname: Sun
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002277:Carcinoma; D002681:China / Q000453:epidemiology; D019353:Endemic Diseases; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018908:Muscle Weakness / Q000209:etiology*; D009133:Muscular Atrophy / Q000209:etiology*; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms / Q000453:epidemiology / Q000532:radiotherapy*; D009334:Neck Muscles; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects*; D012189:Retrospective Studies; D012307:Risk Factors; D055815:Young Adult