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Table 1 Baseline (pre-treatment) characteristics of SCMs without neck muscle spasm and those with neck muscle spasm

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

Variables SCMs without neck muscles spasm SCMs with neck muscles spasm P value
Group number 254 50  
Sex    0.003
 Male 199 (78.35%) 29 (58.00%)  
 Female 55 (21.65%) 21 (42.00%)  
Age (years)    0.471
  ≤ 41 131 (51.57%) 23 (46.00%)  
  > 41 123 (48.43%) 27 (54.00%)  
T stage    0.356
 T1–2 61 (24.02%) 9 (18.00%)  
 T3–4 193 (75.98%) 41 (82.00%)  
N stage    0.002
 N0–1 127 (50.00%) 13 (26.00%)  
 N2–3 127 (50.00%) 37 (74.00%)  
Smoking status    0.799
 Yes 86 (33.86%) 16 (32.00%)  
 No 168 (66.14%) 34 (68.00%)  
Drinking status    0.851
 Yes 38 (14.96%) 8 (16.00%)  
 No 216 (85.04%) 42 (84.00%)  
Induction chemotherapy    0.839
 Yes 123 (48.43%) 25 (50.00%)  
 No 131 (50.57%) 25 (50.00%)  
Concurrent chemotherapy    0.851
 Yes 216 (85.04%) 42 (84.00%)  
 No 38 (14.96%) 8 16.00%)  
Neck dissection    0.324
 Yes 8 (3.15%) 3 (6.00%)  
 No 246 (96.85%) 47 (94.00%)  
D mean 50.54 Gy (38.04 Gy – 58.91 Gy) 62.05 Gy (61.22 Gy – 62.35 Gy) < 0.001
D min 2.68 Gy (1.04 Gy – 29.44 Gy) 35.88 Gy (30.35 Gy – 39.58 Gy) < 0.001
D max 68.82 Gy (66.24 Gy – 71.46 Gy) 70.80 Gy (68.58 Gy −72.51 Gy) 0.048
V20a 84.94% (61.87% – 100%) 100% (100% – 100%) < 0.001
V25 81.70% (59.84% – 100%) 100% (100% – 100%) < 0.001
V30 79.52% (57.88% – 99.99%) 100% (100% – 100%) < 0.001
V35 77.57% (56.23% – 99.76%) 100% (99.88% – 100%) < 0.001
V40 75.57% (54.40% – 98.99%) 99.89% (99.22% – 100.00%) < 0.001
V45 74.00% (52.43% – 96.44%) 99.07% (97.67% – 99.70%) < 0.001
V50 70.87% (47.81% – 90.72%) 96.32% (93.59% – 98.32%) < 0.001
V55 64.00% (41.94% – 78.86%) 87.74% (84.56% – 91.79%) < 0.001
V60 39.02% (23.11% – 52.10%) 68.33% 64.01% – 72.25%) < 0.001
V65 8.16% (0.97% – 20.59%) 35.01% (23.10% – 41.22%) < 0.001
V70 0.00% (0.00% – 0.76%) 1.66% (0.00% – 13.78%) < 0.001
V75 0.00% (0.00% – 0.00%) 0.00% (0.00% – 0.00%) 0.010
V80 0.00% (0.00% – 0.00%) 0.00% (0.00% – 0.00%) 0.537
D20b 63.12 Gy (60.59 Gy – 65.28 Gy) 66.74 Gy (64.93 Gy – 68.01 Gy) < 0.001
D25 62.39 Gy (59.74 Gy – 64.31 Gy) 66.04 Gy (64.30 Gy – 67.35 Gy) < 0.001
D30 61.69 Gy (58.95 Gy – 63.39 Gy) 65.27 Gy (63.61 Gy – 66.61 Gy) < 0.001
D35 60.76 Gy (57.74 Gy – 62.53 Gy) 64.76 Gy (63.05 Gy – 65.92 Gy) < 0.001
D40 59.79 Gy (55.88 Gy – 61.70 Gy) 63.97 Gy (62.68 Gy – 64.85 Gy) < 0.001
D45 59.06 Gy (53.84 Gy – 61.01 Gy) 63.23 Gy (62.31 Gy – 64.05 Gy) < 0.001
D50 58.17 Gy (49.85 Gy – 60.38 Gy) 62.48 Gy (61.59 Gy – 63.14Gy) < 0.001
D55 57.52 Gy (38.66 Gy – 59.55 Gy) 61.75 Gy (61.01 Gy – 62.44 Gy) < 0.001
D60 56.26 Gy (27.73 Gy – 58.83 Gy) 61.10 Gy (60.35 Gy – 61.67 Gy) < 0.001
D65 54.85 Gy (16.57 Gy – 58.14 Gy) 60.22 Gy (59.61 Gy – 60.86 Gy) < 0.001
D70 51.52 Gy (9.49 Gy – 57.19 Gy) 59.80 Gy (58.47 Gy – 57.81 Gy) < 0.001
D75 43.68 Gy (5.57 Gy – 56.15 Gy) 58.42 Gy (57.51 Gy – 59.37 Gy) < 0.001
D80 35.34 Gy (3.21 Gy – 54.78 Gy) 57.21 Gy (56.01 Gy – 58.29 Gy) < 0.001
  1. Abbreviations: SCM sternocleidomastoid muscle, Dmean Mean dose to the sternocleidomastoid muscle, Dmax Maximum dose to the sternocleidomastoid muscle; V20a is the percentage of the sternocleidomastoid muscle volume that received more than 20 Gy; D20b is the dose to 20% of the sternocleidomastoid muscle volume; the other dosimetric parameters are reported in a similar manner