Table 2.

The characteristics of tumors and central lymph nodes in the 3 groups.

Variables	Group A (n = 383)	Group B (n = 297)	Group C (n = 22)	P value†	P value‡
Largest tumor size (mm)	14.4 ± 9.7	13.2 ± 9.9	13.6 ± 7.6	0.133	0.709
Multifocality	106	70	3	0.251	0.216
Primary tumor location				1	0.217
Upper	108	84	3
Middle	162	122	14
Lower	103	80	3
Isthmus	10	11	2
T classification				0.384	0.655
T1	145	123	7
T2	12	8	1
T3	206	158	14
T4	20	8	0
N classification				0.079	0.822
N0	132	122	8
N1	251	175	14
AJCC stage
I–II	250	194	11	1	0.171
III–IV	133	103	11
Gross extrathyroidal extension	155	123	5	0.814	0.118
Number of harvested lymph nodes*	12.2 ± 6.5	10.6 ± 6.1	11.7 ± 6.5	0.001	0.731
Number of metastatic lymph nodes*	3.1 ± 4.2	2.5 ± 3.5	2.3 ± 3.2	0.024	0.368

*Central lymph nodes; ^†groups A vs B; ^‡groups A vs C.

AJCC, American Joint Committee on Cancer.