Characteristics of participants
A total of 455 patients, including 126 male and 329 females with DTC, participated in this study. Table 1 describes the pathological characteristics of DTC and the metabolic characteristics of the participants at recruitment. The mean age of the participants was 44.19. The mean dimension of the primary tumor was 1.22 cm, and in most cases, was less than 4 cm. About 44.40% of the participants had a tumor size less than 1cm. All the included participants received central lymph node dissection according to our surgical protocol. And lateral lymph node dissection was performed in 44 participants (9.67%). A total of 202 (44.4%) participants had metastatic lymph nodes. About 40% of the tumors were multifocal, and approximately 20% of the tumors were bilateral. Capsule invasion was found in 71.87% (327/455) of the cases. Extrathyroid invasion was found in 8.57% (39/455) of the patients. Almost 38% of the patients had blood pressure ≥ 130/85mmHg, and 6.81% of the patients had diabetes. High TG was detected in 24.62% (112/455) of the participants. While low HDL was detected in 23.52% (107/455) of the participants, 82 of the participants had abdominal adiposity. A total of 221 (48.57%) patients had one or two metabolic components, and 85 (18.68%) patients had three or more than three metabolic components and were diagnosed as MetS.
Table 1
Clinicopathological characteristics of included patients.
Characteristics
|
Patients (n = 455)
|
%
|
Sex
|
|
|
Male
|
126
|
27.69
|
Female
|
329
|
72.31
|
Age
|
44.19 ± 11.68
|
/
|
TSH
|
2.03 ± 1.47 IU/ml
|
/
|
Tumor size
|
|
|
Mean
|
1.22 ± 0.94 cm
|
/
|
≤ 1cm
|
243
|
53.41
|
> 1cm
|
212
|
46.59
|
Lymph node metastasis
|
|
|
Negative
|
253
|
55.60
|
Positive
|
202
|
44.40
|
Multifocal tumor
|
|
|
No
|
314
|
69.01
|
Yes
|
141
|
30.99
|
Bilaterality
|
|
|
No
|
355
|
78.02
|
Yes
|
100
|
21.98
|
Capsule invasion
|
|
|
No
|
128
|
28.13
|
Yes
|
327
|
71.87
|
Extrathyroid invasion
|
|
|
No
|
416
|
91.43
|
Yes
|
39
|
8.57
|
Blood pressure ≥ 130/85mmHg
|
|
|
No
|
284
|
62.42
|
Yes
|
171
|
37.58
|
Diabetes
|
|
|
No
|
424
|
93.19
|
Yes
|
31
|
6.81
|
High TG (≥ 2.3 mmol/L)
|
|
|
No
|
343
|
75.38
|
Yes
|
112
|
24.62
|
Low HDL-C (< 1.0 mmol/L)
|
|
|
No
|
348
|
76.48
|
Yes
|
107
|
23.52
|
Abdominal adiposity
|
|
|
No
|
373
|
81.98
|
Yes
|
82
|
18.02
|
Number of MetS components
|
|
|
0
|
149
|
32.82
|
1–2
|
221
|
48.57
|
3–5
|
85
|
18.68
|
Values are expressed as mean ± standard deviation or number (%). |
TSH, thyroid stimulating hormone. TG, triglycerides. HDL-C, high-density lipoprotein cholesterol. MetS, metabolic syndrome. |
Relationship between MetS and clinicopathological features of DTC
The clinical data and the tumor characteristics, according to the presence or absence of MetS, are reported in Table 2. More men suffered from metabolic syndrome than women. No significant difference in TSH levels was observed between those patients with and without MetS. The patients with MetS were older (p = 0.035) and had larger tumors (p = 0.019) and more lymph node metastasis (p = 0.007) than the patients without any components of MetS. The cases with one or two metabolic components showed intermediate figures. In the MetS group, the patients more frequently had a multifocal (p = 0.001) and bilateral (p = 0.016) disease compared to patients without MetS. Patients with MetS also had a higher risk of developing capsule invasion (p = 0.016) and extrathyroid invasion (p = 0.014).
Table 2
Clinicopathologic characteristics for patients with and without metabolic syndrome
Characteristics
|
Non-MetS
|
MetS
|
p
|
0 components
|
1–2 components
|
3–5 components
|
Sex
|
|
Male
|
17 (11.41)
|
65 (29.41)
|
44 (51.76)
|
0.001
|
Female
|
132 (88.59)
|
156 (70.59)
|
41 (48.24)
|
Age (mean ± SD)
|
42.30 ± 12.72
|
45.02 ± 11.10
|
45.36 ± 10.95
|
0.035
|
TSH (mean ± SD)
|
2.00 ± 1.29 IU/ml
|
2.00 ± 1.57 IU/ml
|
2.15 ± 1.55 IU/ml
|
0.318
|
Tumor size
|
|
Mean ± SD
|
1.14 ± 0.86 cm
|
1.21 ± 1.03 cm
|
1.40 ± 0.84 cm
|
0.019
|
≤ 1
|
90 (60.40)
|
122 (55.20)
|
31 (36.47)
|
0.001
|
> 1
|
59 (39.60)
|
99 (44.80)
|
54 (63.53)
|
Lymph node metastasis
|
|
No
|
93 (62.42)
|
125 (56.56)
|
35 (41.18)
|
0.007
|
Yes
|
56 (37.58)
|
96 (43.44)
|
50 (58.82)
|
Multifocal tumor
|
|
No
|
108 (72.48)
|
159 (71.95)
|
47 (55.29)
|
0.010
|
Yes
|
41 (27.52)
|
62 (28.05)
|
38 (44.71)
|
Bilaterality
|
|
No
|
127 (87.59)
|
171 (78.44)
|
57 (67.06)
|
0.001
|
Yes
|
18 (12.41)
|
47 (21.56)
|
28 (32.94)
|
Capsule invasion
|
|
No
|
54 (36.24)
|
57 (25.79)
|
17 (20.00)
|
0.016
|
Yes
|
95 (63.76)
|
164 (74.21)
|
68 (80.00)
|
Extrathyroid invasion
|
|
No
|
140 (93.96)
|
205 (92.76)
|
71 (83.53)
|
0.014
|
Yes
|
9 (6.04)
|
16 (7.24)
|
14 (16.47)
|
Values are expressed as mean ± standard deviation or number (%). A two-tailed P value of less than 0.05 was considered statistically significant. |
TSH, thyroid stimulating hormone. MetS, metabolic syndrome. |
A multivariate analysis was performed to detect the correlation between MetS and the clinicopathological features. As shown in Table 3, after correction for age, sex, and TSH, MetS was still a risk factor for larger tumors (OR = 2.25, 95% CI: 1.25–4.06), lymph node metastasis (OR = 3.14, 95% CI: 1.68–5.87), multifocal tumor (OR = 2.38, 95% CI: 1.30–4.35), bilateral disease (OR = 3.39, 95% CI: 1.67–6.90), capsule invasion (OR = 2.26, 95% CI: 1.15–4.45), and extrathyroid invasion (OR = 4.44, 95% CI: 1.67–11.81). Those patients with one or two metabolic components had higher risks for bilaterality (OR = 1.90, 95% CI:1.04–3.46) and capsule invasion (OR = 1.68, 95% CI: 1.05–2.70). However, no differences were found in tumor size, lymph node metastasis, multifocal tumors, and extrathyroid invasion between patients with one or two metabolic components and patients without any metabolic components.
Table 3
Multivariate ORs of metabolic syndrome for prognostic factors of differentiated thyroid cancer
Clinicopathological features
|
Non-MetS
(0 components)
|
Non-MetS
(1–2 components)
|
P
|
MetS
(≥ 3 components)
|
P
|
Tumor size
|
1
|
1.17 (0.75–1.82)
|
0.481
|
2.25 (1.25–4.06)
|
0.007
|
Lymph node metastasis
|
1
|
1.53 (0.96–2.45)
|
0.075
|
3.14 (1.68–5.87)
|
0.001
|
Multifocal tumor
|
1
|
1.07 (0.67–1.73)
|
0.773
|
2.38 (1.30–4.35)
|
0.005
|
Bilaterality
|
1
|
1.90 (1.04–3.46)
|
0.037
|
3.39 (1.67–6.90)
|
0.001
|
Capsule invasion
|
1
|
1.68 (1.05–2.70)
|
0.031
|
2.26 (1.15–4.45)
|
0.018
|
Extrathyroid invasion
|
1
|
1.44 (0.60–3.43)
|
0.413
|
4.44 (1.67–11.81)
|
0.003
|
Adjusted for age, sex and thyroid stimulating hormone. |
MetS, metabolic syndrome. |
Relationship between metabolic components and clinicopathological features of DTC
We further analyzed the relationship between each of the five metabolic components and the clinicopathological features of DTC. As shown in Fig. 1, after adjusting for age, sex, and TSH, a blood pressure ≥ 130/85mmHg was associated with lymph node metastasis (OR = 1.58, 95% CI: 1.03–2.40), bilateral disease (OR = 2.63, 95% CI: 1.62–4.25), and extrathyroid invasion (OR = 3.50, 95% CI: 1.71–7.16). Diabetes had no significant association with any of the clinicopathological features. Abdominal adiposity was associated with lymph node metastasis (OR = 2.06, 95% CI: 1.23–3.46). High TG was a risk factor for multifocal tumors (OR = 1.72, 95% CI: 1.08–2.74) and capsule invasion (OR = 1.90, 95% CI: 1.09–3.32). Low HDL was associated with lymph node metastasis (OR = 3.02, 95% CI: 1.83–4.99), multifocal tumors (OR = 1.94, 95% CI: 1.19 − 3.17), bilateral tumors (OR = 1.91, 95% CI: 1.12 − 3.26), and extrathyroid invasion (OR = 2.29, 95% CI: 1.06 − 4.94).