The Evolution of and Risk Factors for Neck Muscle Atrophy and Weakness in Nasopharyngeal Carcinoma Treated With Intensity-Modulated Radiotherapy

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.

Dose-volume relationships for moderate or severe neck muscle atrophy after intensity-modulated radiotherapy in patients with nasopharyngeal carcinoma

“…Grade 2–3 SCM atrophy (SCM atrophy ratio >40%) was chosen as the study endpoint, as the risk of developing neck muscle weakness appears to increase when the degree of neck muscle atrophy is higher. Our previous and current research showed significant associations between the grade of SCM atrophy and the grade of neck weakness 21 . The current study found that 9.1% of SCMs suffered moderate or severe SCM atrophy, and 22.46% of patients had grade 2–3 neck weakness, 3-years post-IMRT.…”

“…We explored the risk factors (age, gender, T stage, N stage, chemotherapy, the length of time after IMRT and weight change ratio) for IMRT-induced SCM atrophy in previous research. Only the N stage and the length of time after IMRT were found to be associated with IMRT-induced SCM atrophy 21 . Therefore, in the present study patients were examined 3 years after the completion of IMRT in order to exclude the effect of time on the occurrence of this late complication.…”

Combined prognostic value of pretreatment anemia and cervical node necrosis in patients with nasopharyngeal carcinoma receiving intensity‐modulated radiotherapy: A large‐scale retrospective study

“…Treatment strategies were designed using standard protocols depending on clinical TNM stage and the general patient condition. In the relevant study period, institutional guidelines recommended concurrent chemoradiotherapy ± neoadjuvant/adjuvant chemotherapy for stage II to IVB as described previously . Every patient was treated with IMRT at one fraction/day, 5 days per week.…”

“…Every patient was treated with IMRT at one fraction/day, 5 days per week. IMRT was performed as described previously .…”

Patient- and treatment-related risk factors associated with neck muscle spasm in nasopharyngeal carcinoma patients after intensity-modulated radiotherapy

“…The dosimetric parameters were obtained from dose volume histograms (DVHs) of the SCM. We re-delineated bilateral SCMs according to our previously proposed methods [ 16 ] to generate the bilateral neck DVHs for each patient using the CERR DICOM-RT toolbox (version 3.0 beta 3; School of Medicine, Washington University, St. Louis, USA). The following dosimetric parameters were collected: mean dose (Dmean), maximum dose (Dmax), minimum dose (Dmin), percentage of the SCM volume that received more than X Gy (VX), the dose received by X% of the SCM volume (DX); values of X were 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75 and 80.…”