Fig. 1Inclusion and exclusion flow chart. PTC, papillary thyroid cancer; Tg, thyroglobulin; Anti-Tg, anti-thyroglobulin.
Table 1Demographic and Clinical Characteristics of Filipino Patients with Low-Risk Papillary Thyroid Cancer (n=145)
Characteristic |
Value |
Age at diagnosis, yr |
39.74±10.67 |
Male sex |
15 (10.34) |
Family history |
2 (1.38) |
Smoking history |
9 (6.21) |
Prophylactic LN dissection |
5 (3.45) |
Tumor diameter, cm |
2.29±1.37 |
Multifocality |
25 (17.24) |
RAI therapy given |
92 (63.45) |
Time to initial RAI from surgery, mo |
8±9.69 |
Initial Tg level, ≤2 ng/mL |
94 (64.83) |
Initial anti-Tg antibody level, ≤50 U/mL |
128 (88.27) |
Extent of TSH suppression, ≤0.27 mU/L |
100 (68.97) |
Follow-up duration, mo |
112.28±63.03 |
Table 2Comparison of Baseline Characteristics among Patients Who Did and Did Not Undergo RAI
Variable |
With RAI (n=92) |
Without RAI (n=53) |
P value |
Age at diagnosis, yr |
39±9.18 |
39±12.94 |
0.871 |
Male sex |
9 (9.78) |
6 (11.32) |
0.783 |
Family history of PTC |
2 (2.17) |
0 |
0.533 |
Smoking history |
5 (5.43) |
4 (7.55) |
0.724 |
Prophylactic LN dissection |
4 (4.35) |
1 (1.89) |
0.653 |
Tumor diameter, cm |
2.33±1.39 |
2.23±1.36 |
0.967 |
<2 |
38 (41.3) |
21 (39.62) |
2-4 |
45 (48.9) |
27 (50.9) |
>4 |
9 (9.8) |
5 (9.43) |
Multifocality |
17 (18.48) |
8 (15.1) |
0.655 |
Initial Tg level, ≤2 ng/mL |
85 (92.4) |
9 (16.98) |
<0.005 |
Initial anti-Tg antibody level, ≤50 U/mL |
84 (91.3) |
44 (83.02) |
0.18 |
TSH suppression, ≤0.27 mU/L |
76 (82.61) |
24 (45.28) |
<0.005 |
Follow-up duration, mo |
113±53.39 |
109±77.47 |
0.702 |
Recurrence |
7 (7.61) |
44 (83.02) |
<0.005 |
Locoregional |
7 (7.61) |
35 (66.04) |
<0.005 |
Distant |
0 |
9 (16.98) |
<0.005 |
Table 3Univariate Logistic Regression Analysis of Risk Factors for Disease Recurrence among Patients with Low-Risk Papillary Thyroid Cancer
Variable |
With recurrence (n=51) |
Without recurrence (n=94) |
Relative risk |
P value (95% CI) |
Age at diagnosis, yr |
38.98±12.66 |
40.15±9.46 |
0.99 |
0.528 (0.95-1.02) |
Male sex |
6 (11.76) |
9 (9.57) |
1.26 |
0.68 (0.42-3.76) |
Family history of PTC |
1 (1.96) |
1 (1.06) |
1.86 |
0.663 (0.11-30.37) |
Smoking history |
4 (7.84) |
5 (5.32) |
1.51 |
0.550 (0.39-5.91) |
Prophylactic LN dissection |
2 (3.92) |
3 (3.19) |
1.24 |
0.818 (0.20-7.66) |
Tumor diameter, cm |
2.59±1.32 |
2.13±1.38 |
|
|
<2 |
14 (27.45) |
45 (47.87) |
2.43 |
|
2-4 |
31 (60.8) |
41 (43.62) |
2.41 |
0.022 (1.14-5.19) |
>4 |
6 (11.76) |
8 (8.51) |
|
0.156 (0.71-8.14) |
Multifocality |
8 (15.69) |
17 (18.08) |
0.843 |
0.715 (0.34-2.11) |
Initial Tg level, ≤2 ng/mL |
8 (15.7) |
86 (91.5) |
0.017 |
<0.005 (0.01-0.049) |
Initial anti-Tg antibody level, ≤50 U/mL |
41 (80.39) |
87 (92.55) |
0.329 |
0.036 (0.117-0.93) |
TSH suppression, ≤0.27 mU/L |
22 (43.14) |
78 (82.98) |
0.16 |
<0.005 (0.07-0.34) |
RAI therapy |
7 (13.73) |
85 (90.43) |
0.02 |
<0.005 (0.01-0.05) |
Table 4Multivariate Logistic Regression Analysis of Risk Factors for Recurrence in Filipinos with Low-Risk Papillary Thyroid Cancer
Significant risk factor |
Relative risk |
P value (95% CI) |
Tumor diameter, cm |
|
|
2-4 |
9.17 |
0.012 (1.62-51.88) |
>4 |
16.46 |
0.04 (1.14-237.31) |
Family history of PTC |
67.27 |
0.018 (2.03-2,228.96) |
RAI therapy |
0.026 |
<0.005 (0.01-0.023) |
Initial Tg level, ≤2 ng/mL |
0.049 |
<0.005 (0.01-0.23) |
Initial anti-Tg antibody level, ≤50 U/mL |
0.087 |
0.019 (0.011-0.67) |