Fig. 1Receiver operating characteristic curve showing the cut-off value of the diagnostic category of the Bethesda system for the diagnosis of histologically-confirmed malignant thyroid by cytopathologists A, B, C, and D. The cut-off values have the following values derived from the area under the curve: (A) cytopathologist A: cut-off value>1, 0.513; cut-off value>2, 0.910; cut-off value>3, 0.887; cut-off value>4, 0.891; cut-off value>5, 0.738; (B) cytopathologist B: cut-off value>1, 0.507; cut-off value>2, 0.900; cut-off value>3, 0.871; cut-off value>4, 0.871; cut-off value>5, 0.654; (C) cytopathologist C: cut-off value>1, 0.544; cut-off value>2, 0.914; cut-off value>3, 0.888; cut-off value>4, 0.888; cut-off value>5, 0.706; (D) cytopathologist D: cut-off value>1, 0.528; cut-off value>2, 0.921; cut-off value>3, 0.881; cut-off value>4, 0.879; cut-off value>5, 0.646.
Table 1.Distribution of the diagnostic categories in all cases by each cytopathologist (%)
Diagnostic category of Bethesda system |
Cytopathologists
|
Total (n = 1,730) |
A (n = 348) |
B (n = 330) |
C (n = 382) |
D (n = 670) |
I |
28 (8.0) |
50 (15.1) |
63 (16.5) |
89 (13.3) |
230 (13.3) |
II |
128 (36.8) |
151 (45.8) |
122 (31.9) |
301 (44.9) |
702 (40.6) |
III |
41 (11.8) |
18 (5.5) |
40 (10.5) |
58 (8.7) |
157 (9.1) |
IV |
5 (1.4) |
0 (0) |
1 (0.3) |
1 (0.1) |
7 (0.4) |
V |
57 (16.4) |
66 (20.0) |
75 (19.6) |
137 (20.5) |
335 (19.3) |
VI |
89 (25.6) |
45 (13.6) |
81 (21.2) |
84 (12.5) |
299 (17.3) |
Table 2.Distribution of the outcomes and malignancy rate in the follow-up cases (%)
Diagnostic category of Bethesda system |
Follow-up diagnosis
|
BN |
PTC |
MTC |
FC |
PD |
Malignancy |
I (n = 116) |
75 (64.7) |
41 (35.3) |
0 (0) |
0 (0) |
0 (0) |
41 (35.3) |
II (n = 702) |
663 (94.5) |
36 (5.1) |
0 (0) |
2 (0.3) |
1 (0.1) |
39 (5.6) |
III (n = 126) |
39 (30.9) |
84 (66.7) |
1 (0.8) |
2 (1.6) |
0 (0) |
87 (69.0) |
IV (n = 4) |
2 (50.0) |
2 (50.0) |
0 (0) |
0 (0) |
0 (0) |
2 (50.0) |
V (n = 314) |
4 (1.3) |
306 (97.4) |
3 (1.0) |
0 (0) |
1 (0.3) |
310 (98.7) |
VI (n = 285) |
3 (1.1) |
282 (98.9) |
0 (0) |
0 (0) |
0 (0) |
282 (98.9) |
Table 3.Distribution of the malignancy rate in follow-up cases by each cytopathologist (%)
Diagnostic category of Bethesda system |
Cytopathologists
|
A (M/T) |
B (M/T) |
C (M/T) |
D (M/T) |
I |
41.2 (7/17) |
48.4 (15/31) |
28.0 (7/25) |
27.9 (12/43) |
II |
4.7 (6/128) |
4.0 (6/151) |
7.4 (9/122) |
6.0 (18/301) |
III |
63.6 (21/33) |
73.3 (11/15) |
70.0 (21/30) |
70.8 (34/48) |
IV |
33.3 (1/3) |
0 (0/0) |
0 (0/0) |
100.0 (1/1) |
V |
100.0 (51/51) |
95.4 (62/65) |
100.0 (68/68) |
99.2 (129/130) |
VI |
98.8 (80/81) |
100.0 (43/43) |
98.7 (78/79) |
98.8 (81/82) |
Total |
53.0 (166/313) |
44.9 (137/305) |
56.5 (183/324) |
45.5 (275/605) |
Table 4.Sensitivity, specificity, false negative rate, false positive rate, positive predictive value, and negative predictive value of the malignancy rate by each cytopathologist (%)
|
Cytopathologists
|
|
A |
B |
C |
D |
Sensitivity |
79.5 |
76.6 |
79.8 |
76.7 |
Specificity |
98.0 |
98.2 |
99.3 |
99.4 |
False negative rate |
20.5 |
23.4 |
20.2 |
23.3 |
False positive rate |
2.0 |
1.8 |
0.7 |
0.6 |
Positive predictive value |
97.8 |
97.2 |
99.3 |
99.1 |
Negative predictive value |
80.9 |
83.8 |
79.1 |
83.7 |
Table 5.Comparison of the distribution of the diagnostic categories of the present report with that of other reports (%)
Diagnostic category of Bethesda system |
Present study |
Mondal et al. [3] |
Jo et al. [4] |
Yassa et al. [5] |
Yang et al. [6] |
Nayar and Ivanovic [7] |
Theoharis et al. [8] |
Mufti and Molah [9] |
Baloch et al. [10] |
Stamataki et al. [11] |
Wu et al. [12] |
Lee et al. [13] |
I |
13.3 |
1.2 |
18.6 |
7.0 |
10.4 |
5.0 |
11.1 |
11.6 |
17.5 |
4.0 |
20.1 |
10.0 |
II |
40.6 |
87.5 |
59.0 |
66.0 |
64.6 |
64.0 |
73.8 |
77.6 |
15.8 |
74.6 |
39.0 |
67.7 |
III |
9.1 |
1.0 |
3.4 |
4.0 |
3.2 |
18.0 |
3.0 |
0.8 |
9.8 |
6.7 |
27.2 |
3.1 |
IV |
0.4 |
4.2 |
9.7 |
9.0 |
11.6 |
6.0 |
5.5 |
4.0 |
16.5 |
- |
8.4 |
0.6 |
V |
19.3 |
1.4 |
2.3 |
9.0 |
2.6 |
2.0 |
1.4 |
2.4 |
19.1 |
2.8 |
2.6 |
5.1 |
VI |
17.3 |
4.7 |
7.0 |
5.0 |
7.6 |
5.0 |
5.2 |
3.6 |
21.3 |
11.9 |
2.7 |
13.0 |
Table 6.Comparison of the distribution of the malignancy rate of the present report with that of other reports (%)
Diagnostic category of Bethesda system |
Present study |
Mondal et al. [3] |
Jo et al. [4] |
Yassa et al. [5] |
Yang et al. [6] |
Nayar and Ivanovic [7] |
Theoharis et al. [8] |
Mufti and Molah [9] |
Baloch et al. [10] |
Stamataki et al. [11] |
Wu et al. [12] |
Lee et al. [13] |
I |
35.3 |
0 |
8.9 |
10.0 |
10.7 |
9.0 |
- |
20.0 |
64.0 |
30.0 |
12.0 |
77.8 |
II |
5.6 |
4.5 |
11.0 |
0.3 |
0.7 |
2.0 |
9.8 |
3.1 |
11.0 |
6.0 |
8.0 |
0 |
III |
69.0 |
20.0 |
17.0 |
24.0 |
19.2 |
6.0 |
48.0 |
50.0 |
50.0 |
33.0 |
27.0 |
79.0 |
IV |
50.0 |
30.6 |
25.4 |
28.0 |
32.2 |
14.0 |
34.0 |
20.0 |
63.0 |
67.0 |
33.0 |
61.5 |
V |
98.7 |
75.0 |
70.0 |
60.0 |
64.8 |
53.0 |
87.0 |
80.0 |
71.0 |
- |
68.0 |
97.6 |
VI |
98.9 |
97.8 |
98.1 |
97.0 |
98.4 |
97.0 |
100.0 |
100.0 |
100.0 |
100.0 |
100.0 |
100.0 |