Therapeutic Outcome of Second Primary Malignancies in Patients with Well-Differentiated Thyroid Cancer

Table 1

Clinical features of 2,864 cases of well-differentiated thyroid cancer with or without second primary malignancies (SPMs) between 1984 and 2013.

Clinical characteristic	Total	With SPM	Without SPM
Patient number	2,864	200 (7.0%)	2,664 (93.0%)
Gender (female)	2,256 (78.8%)	139 (69.5%)	2,117 (79.5%)	0.0009
Age at diagnosis (year)	44.0 ± 14.4	51.6 ± 13.2	43.5 ± 14.4	0.0001
Mean tumor size (cm)	2.4 ± 1.7	2.4 ± 1.5	2.4 ± 1.7	0.6793
Thyroid operative method				0.0035
Total thyroidectomy	2425 (84.7%)	155 (77.5%)	2270 (85.2%)
Less than total thyroidectomy	439 (15.3%)	45 (22.5%)	394 (14.8%)
TNM stage				0.0001
Stage I	1950 (68.1%)	101 (50.5%)	1849 (69.4%)
Stage II	287 (10.0%)	27 (13.5%)	260 (9.8%)
Stage III	229 (8.0%)	25 (12.5%)	204 (7.6%)
Stage IV	398 (13.9%)	47 (23.5%)	351 (13.2%)
Nonremission	466 (16.3%)	48 (24.0%)	418 (15.7%)	0.0021
Follow-up period (year)	9.5 ± 6.7	9.2 ± 6.6	9.5 ± 6.7	0.5575
Postoperative ^131I accumulative dose (mCi)	130.6 ± 193.6	166.3 ± 258.2	127.9 ± 187.6	0.0068
Radiation therapy	143 (5.0%)	24 (12.0%)	119 (4.5%)	0.0001
Multifocality	662 (23.1%)	50 (25.0%)	612 (23.0%)	0.5119
Mortality due to thyroid cancer	163 (5.7%)	18 (9.0%)	145 (5.4%)	0.0362
Overall mortality	301 (10.5%)	74 (37.0%)	227 (8.5%)	0.0001

Well-differentiated: including papillary, follicular, and Hürthle’s cell thyroid cancer.