World J Oncol

World Journal of Oncology, ISSN 1920-4531 print, 1920-454X online, Open Access

Article copyright, the authors; Journal compilation copyright, World J Oncol and Elmer Press Inc

Journal website https://www.wjon.org

Original Article

Volume 13, Number 3, June 2022, pages 136-144

Long-Term Survival in Patients With Papillary Thyroid Cancer Who Did Not Undergo Prophylactic Central Lymph Node Dissection: A SEER-Based Study

Figure 1. Kaplan-Meier curves for thyroid cancer-specific survival (TCSS) and overall survival (OS) in patients with and without prophylactic central lymph node dissection (pCLND). (a) Thyroid cancer-specific survival. (b) Overall survival.

**Table 1.** Baseline Characteristics of Thyroid Cancer Patients According to Prophylactic Central Lymph Node Dissection
Characteristics	Without CLND	With CLND	P
CLND: central lymph node dissection; SD: standard deviation.
Patients number	38,205 (61.26)	24,157 (38.74)	/
Age (mean ± SD)	50.02 ± 14.13	46.98 ± 13.83	< 0.001
< 55	23,686 (62.00)	16,997 (70.36)	< 0.001
≥ 55	14,519 (38.00)	7,160 (29.64)
Sex
Male	7,414 (19.41)	3,753 (15.54)	<0.001
Female	30,791 (80.38)	20,404 (84.46)
Race
White	30,495 (79.82)	20,609 (85.25)	< 0.001
Black	3,492 (9.14)	990 (4.10)
Other	4,218 (11.04)	2,558 (10.59)
T stage
T1	31,419 (82.24)	19,480 (80.64)	< 0.001
T2	6,786 (17.76)	4,667 (19.36)
Multifocal
No	25,313 (66.26)	14,013 (58.01)	< 0.001
Yes	12,522 (32.78)	9,969 (41.27)
Unknown	370 (0.97)	175 (0.72)
Surgery
Total thyroidectomy	27,550 (72.11)	20,607 (85.30)	< 0.001
Other surgery	10,655 (27.83)	3,536 (14.64)
Unknown	24 (0.06)	14 (0.06)
Radiation
No	25,177 (65.90)	14,513 (60.08)	< 0.001
Yes	13,028 (34.10)	9,644 (39.92)
Median follow-up (months)	81	75	/
Survival status
Alive	36,302 (95.02)	23,515 (97.34)	< 0.001
Death from thyroid cancer	122 (0.32)	44 (0.18)
Death from other causes	1,781 (4.66)	598 (2.48)

Table 1. Baseline Characteristics of Thyroid Cancer Patients According to Prophylactic Central Lymph Node Dissection

Characteristics

Without CLND

With CLND

CLND: central lymph node dissection; SD: standard deviation.

Patients number

38,205 (61.26)

24,157 (38.74)

Age (mean ± SD)

50.02 ± 14.13

46.98 ± 13.83

< 0.001

< 55

23,686 (62.00)

16,997 (70.36)

< 0.001

≥ 55

14,519 (38.00)

7,160 (29.64)

Sex

Male

7,414 (19.41)

3,753 (15.54)

<0.001

Female

30,791 (80.38)

20,404 (84.46)

Race

White

30,495 (79.82)

20,609 (85.25)

< 0.001

Black

3,492 (9.14)

990 (4.10)

Other

4,218 (11.04)

2,558 (10.59)

T stage

31,419 (82.24)

19,480 (80.64)

< 0.001

6,786 (17.76)

4,667 (19.36)

Multifocal

25,313 (66.26)

14,013 (58.01)

< 0.001

Yes

12,522 (32.78)

9,969 (41.27)

Unknown

370 (0.97)

175 (0.72)

Surgery

Total thyroidectomy

27,550 (72.11)

20,607 (85.30)

< 0.001

Other surgery

10,655 (27.83)

3,536 (14.64)

Unknown

24 (0.06)

14 (0.06)

Radiation

25,177 (65.90)

14,513 (60.08)

< 0.001

Yes

13,028 (34.10)

9,644 (39.92)

Median follow-up (months)

Survival status

Alive

36,302 (95.02)

23,515 (97.34)

< 0.001

Death from thyroid cancer

122 (0.32)

44 (0.18)

Death from other causes

1,781 (4.66)

598 (2.48)

**Table 2.** Univariate Variate and Multivariate Fine-Gray Competing Risk Model for Thyroid Cancer Specific Survival
Characteristics	SHR	P	aSHR^a	P
^aAdjusted for age, sex, race, tumor stage, multifocality, surgery of thyroid and radiation. SHR: subdistribution hazard ratio; aSHR: adjusted subdistribution hazard ratio; CLND: central lymph node dissection.
Age
< 55	1 (reference)		1 (reference)
≥ 55	6.91 (4.78 - 10.00)	< 0.001	6.87 (4.74 - 9.95)	< 0.001
Sex
Female	1 (reference)		1 (reference)
Male	2.09 (1.50 - 2.91)	< 0.001	1.53 (1.10 - 2.14)	0.012
Race
White	1 (reference)		1 (reference)
Black	1.30 (0.76 - 2.22)	0.335	1.25 (0.73 - 2.15)	0.411
Other	0.59 (0.31 - 1.12)	0.106	0.65 (0.34 - 1.24)	0.187
Tumor size
T1	1 (reference)		1 (reference)
T2	2.04 (1.47 - 2.84)	< 0.001	2.14 (1.51 - 3.03)	< 0.001
Multifocal
No	1 (reference)		1 (reference)
Yes	0.76 (0.19 - 3.07)	0.701	0.87 (0.19 - 4.06)	0.859
Unknown	0.89 (0.22 - 3.61)	0.866	0.96 (0.20 - 4.53)	0.957
Surgery
Total thyroidectomy	1 (reference)		1 (reference)
Other surgery	0.94 (0.65 - 1.35)	0.720	0.93 (0.63 - 1.38)	0.726
Unknown	7.57 (1.04 - 54.89)	0.045	10.19 (1.15 - 90.21)	0.037
Radiation
No	1 (reference)		1 (reference)
Yes	1.20 (0.88 - 1.63)	0.246	1.15 (0.81 - 1.64)	0.433
CLND
Yes	1 (reference)		1 (reference)
No	1.58 (1.12 - 2.23)	0.010	1.35 (0.95 - 1.93)	0.098

Table 2. Univariate Variate and Multivariate Fine-Gray Competing Risk Model for Thyroid Cancer Specific Survival

Characteristics

SHR

aSHR^a

^aAdjusted for age, sex, race, tumor stage, multifocality, surgery of thyroid and radiation. SHR: subdistribution hazard ratio; aSHR: adjusted subdistribution hazard ratio; CLND: central lymph node dissection.

Age

< 55

1 (reference)

≥ 55

6.91 (4.78 - 10.00)

< 0.001

6.87 (4.74 - 9.95)

< 0.001

Sex

Female

1 (reference)

Male

2.09 (1.50 - 2.91)

< 0.001

1.53 (1.10 - 2.14)

0.012

Race

White

1 (reference)

Black

1.30 (0.76 - 2.22)

0.335

1.25 (0.73 - 2.15)

0.411

Other

0.59 (0.31 - 1.12)

0.106

0.65 (0.34 - 1.24)

0.187

Tumor size

1 (reference)

2.04 (1.47 - 2.84)

< 0.001

2.14 (1.51 - 3.03)

< 0.001

Multifocal

1 (reference)

Yes

0.76 (0.19 - 3.07)

0.701

0.87 (0.19 - 4.06)

0.859

Unknown

0.89 (0.22 - 3.61)

0.866

0.96 (0.20 - 4.53)

0.957

Surgery

Total thyroidectomy

1 (reference)

Other surgery

0.94 (0.65 - 1.35)

0.720

0.93 (0.63 - 1.38)

0.726

Unknown

7.57 (1.04 - 54.89)

0.045

10.19 (1.15 - 90.21)

0.037

Radiation

1 (reference)

Yes

1.20 (0.88 - 1.63)

0.246

1.15 (0.81 - 1.64)

0.433

CLND

Yes

1 (reference)

1.58 (1.12 - 2.23)

0.010

1.35 (0.95 - 1.93)

0.098

**Table 3.** Univariate and Multivariate Cox Proportional Hazards Regression for Overall Survival
Characteristics	HR	P	aHR^a	P
^aAdjusted for age, sex, race, tumor stage, multifocality, surgery of thyroid and radiation. HR: hazard ratio; aHR: adjusted hazard ratio. CLND: central lymph node dissection.
Age
< 55	1 (reference)		1 (reference)
≥ 55	6.35 (5.80 - 6.95)	< 0.001	5.85 (5.33 - 6.41)	< 0.001
Sex
Female	1 (reference)		1 (reference)
Male	1.93 (1.77 - 2.10)	< 0.001	1.54 (1.41 - 1.68)	< 0.001
Race
White	1 (reference)		1 (reference)
Black	1.63 (1.44 - 1.85)	< 0.001	1.59 (1.41 - 1.81)	< 0.001
Other	0.51 (0.43 - 0.61)	< 0.001	0.56 (0.47 - 0.67)	< 0.001
Tumor size
T1	1 (reference)		1 (reference)
T2	1.02 (0.93 - 1.13)	0.645	1.24 (1.12 - 1.37)	< 0.001
Multifocal
No	1 (reference)		1 (reference)
Yes	1.01 (0.69 - 1.19)	0.035	0.99 (0.67 - 1.46)	0.975
Unknown	0.92 (0.62 - 1.36)	0.682	0.98 (0.66 - 1.45)	0.915
Surgery
Total thyroidectomy	1 (reference)		1 (reference)
Other surgery	1.29 (1.19 - 1.41)	< 0.001	1.06 (0.97 - 1.16)	0.218
Unknown	1.54 (0.50 - 4.79)	0.453	2.13 (0.68 - 6.70)	0.194
Radiation
No	1 (reference)		1 (reference)
Yes	0.69 (0.63 - 0.75)	< 0.001	0.79 (0.72 - 0.87)	< 0.001
CLND
Yes	1 (reference)		1 (reference)
No	1.72 (1.57 - 1.88)	< 0.001	1.38 (1.26 - 1.51)	< 0.001

Table 3. Univariate and Multivariate Cox Proportional Hazards Regression for Overall Survival

Characteristics

aHR^a

^aAdjusted for age, sex, race, tumor stage, multifocality, surgery of thyroid and radiation. HR: hazard ratio; aHR: adjusted hazard ratio. CLND: central lymph node dissection.

Age

< 55

1 (reference)

≥ 55

6.35 (5.80 - 6.95)

< 0.001

5.85 (5.33 - 6.41)

< 0.001

Sex

Female

1 (reference)

Male

1.93 (1.77 - 2.10)

< 0.001

1.54 (1.41 - 1.68)

< 0.001

Race

White

1 (reference)

Black

1.63 (1.44 - 1.85)

< 0.001

1.59 (1.41 - 1.81)

< 0.001

Other

0.51 (0.43 - 0.61)

< 0.001

0.56 (0.47 - 0.67)

< 0.001

Tumor size

1 (reference)

1.02 (0.93 - 1.13)

0.645

1.24 (1.12 - 1.37)

< 0.001

Multifocal

1 (reference)

Yes

1.01 (0.69 - 1.19)

0.035

0.99 (0.67 - 1.46)

0.975

Unknown

0.92 (0.62 - 1.36)

0.682

0.98 (0.66 - 1.45)

0.915

Surgery

Total thyroidectomy

1 (reference)

Other surgery

1.29 (1.19 - 1.41)

< 0.001

1.06 (0.97 - 1.16)

0.218

Unknown

1.54 (0.50 - 4.79)

0.453

2.13 (0.68 - 6.70)

0.194

Radiation

1 (reference)

Yes

0.69 (0.63 - 0.75)

< 0.001

0.79 (0.72 - 0.87)

< 0.001

CLND

Yes

1 (reference)

1.72 (1.57 - 1.88)

< 0.001

1.38 (1.26 - 1.51)

< 0.001

**Table 4.** Assessing the Survival of Patients Without pCLND Using Multivariate Fine-Gray Model for TCSS and Cox Proportional Hazards Regression Model for OS in Different Subgroups
Subgroups	TCSS^a	P	OS^a	P
^aAdjusted for age, sex, race, tumor stage, multifocality, surgery of thyroid and radiation. TCSS: thyroid cancer-specific survival; OS: overall survival; CLND: central lymph node dissection.
Age
< 55
CLND/yes	1 (reference)		1 (reference)
CLND/no	1.09 (0.53 - 2.27)	0.811	1.22 (1.03 - 1.45)	0.020
≥ 55
CLND/yes	1 (reference)		1 (reference)
CLND/no	1.45 (0.96 - 2.19)	0.079	1.44 (1.29 - 1.61)	< 0.001
Sex
Male
CLND/yes	1 (reference)		1 (reference)
CLND/no	1.75 (0.85 - 3.61)	0.131	1.25 (1.05 - 1.49)	0.011
Female
CLND/yes	1 (reference)		1 (reference)
CLND/no	1.21 (0.80 - 1.82)	0.376	1.43 (1.28 - 1.59)	< 0.001
T stage
T1
CLND/yes	1 (reference)		1 (reference)
CLND/no	1.30 (0.84 - 2.03)	0.240	1.38 (1.25 - 1.53)	< 0.001
T2
CLND/yes	1 (reference)		1 (reference)
CLND/no	1.44 (0.78 - 2.64)	0.242	1.35 (1.11 - 1.66)	0.003

Table 4. Assessing the Survival of Patients Without pCLND Using Multivariate Fine-Gray Model for TCSS and Cox Proportional Hazards Regression Model for OS in Different Subgroups

Subgroups

TCSS^a

OS^a

^aAdjusted for age, sex, race, tumor stage, multifocality, surgery of thyroid and radiation. TCSS: thyroid cancer-specific survival; OS: overall survival; CLND: central lymph node dissection.

Age

< 55

CLND/yes

1 (reference)

CLND/no

1.09 (0.53 - 2.27)

0.811

1.22 (1.03 - 1.45)

0.020

≥ 55

CLND/yes

1 (reference)

CLND/no

1.45 (0.96 - 2.19)

0.079

1.44 (1.29 - 1.61)

< 0.001

Sex

Male

CLND/yes

1 (reference)

CLND/no

1.75 (0.85 - 3.61)

0.131

1.25 (1.05 - 1.49)

0.011

Female

CLND/yes

1 (reference)

CLND/no

1.21 (0.80 - 1.82)

0.376

1.43 (1.28 - 1.59)

< 0.001

T stage

CLND/yes

1 (reference)

CLND/no

1.30 (0.84 - 2.03)

0.240

1.38 (1.25 - 1.53)

< 0.001

CLND/yes

1 (reference)

CLND/no

1.44 (0.78 - 2.64)

0.242

1.35 (1.11 - 1.66)

0.003