Hemithyroidectomy or Thyroidectomy in Thyroid Cancer

In This Article

Abstract and Introduction

Abstract

Objective: For 1–4 cm differentiated thyroid cancer (DTC), current ATA guideline recommended hemithyroidectomy (HT) as an acceptable alternative initial procedure to total or near-total thyroidectomy (TT). The aim of this study was to evaluate benefits and harms of HT, TT in 1–4 cm DTC.

Design: Retrospective cohort study.

Patients: DTC patients aged 18 years or older who underwent initial thyroidectomy in a tertiary medical centre were included from January 2008 to July 2018.

Measurements: The structural persistent/recurrent disease, reoperation rates and surgical complications were compared using Cox proportional regression and logistic regression. Propensity score matching was performed to adjust for related clinicopathological variables.

Results: Among 1824 DTC patients, 795 patients sized 1–4 cm were included. A total of 286 patients underwent HT and 509 patients underwent TT. In the matched analysis, no significant difference in disease-free survival (DFS) between HT and TT was observed during the median follow-up period of 56.5 months (hazard ratio [HR] 0.86; 95% CI, 0.37–2.00; p = .733). The difference in DFS between two groups was consistent regardless of age, sex, tumour size, follow-up duration. Meanwhile, HT was associated with a decreased risk of surgical complications (odds ratio [OR] 0.47, 95% CI 0.31–0.71, p < .001), as well as lower proportion of levothyroxine replacement (p = .007). Two cases in HT group received reoperation. Further multivariate analysis showed surgical procedure was not associated with structural persistence/recurrence (HR 0.68; 95%CI, 0.29–1.58, p = .367).

Conclusions: For patients with 1–4 cm DTC without clinical evidence of lymph node metastasis or extrathyroidal extension, HT was associated with lower risk of surgical complications than TT while provided similar benefits as TT.

Introduction

Thyroid cancer is the most prevalent endocrine malignancy, and its incidence rates have been continuously rising worldwide over the last few decades. Among all thyroid malignancies, differentiated thyroid cancer (DTC) accounts for more than 90%.^[1,2] Despite the rising prevalence, the thyroid cancer-related death rate is reported to be stable at approximately 0.5 cases per 100,000 persons.^[3] As a result, many experts advocated for more conservative management for DTC due to concerns about overdiagnosis and overtreatment.^[4–6]

For the treatment of DTC, especially those larger than 1cm, surgery remains the mainstay. In the United States, over 100,000 thyroid operations are performed annually. Currently, there are two surgical procedures for DTC, namely bilateral procedure [total or near-total thyroidectomy (TT)] and unilateral procedure [hemithyroidectomy (HT)]. The 2015 American Thyroid Association (ATA) guidelines recommended that for patients with thyroid cancer 1–4 cm without extrathyroidal extension (ETE), and clinical evidence of any lymph node (LN) metastases, the initial surgical procedure can be either unilateral or bilateral procedure.^[7] Therefore, shared decision-making may be frequently encountered clinical scenarios in the practice of DTC. To better guide shared decision-making conversation, evidence about options of surgical procedure, their potential benefits and possible harms is needed. Previous evidence indicated TT would improve survival^[8,9] and reduce the risk of recurrence^[10–12] as compared with HT. Meanwhile, TT provides advantages such as enabling the routine use of radioactive iodine (RAI) remnant ablation, clearing microscopic cancer foci in the contralateral lobe and facilitating detection of thyroglobulin for monitoring recurrent/persistent disease during follow-up. In addition, those who chose TT as the initial surgical procedure might be at lower risk of reoperation. However, recent data suggested that clinical outcomes are very similar following HT or TT in patients with 1–4 cm DTC.^[13,14] And more importantly, it was reported that HT is associated with lower rates of surgical complications.^[15–17] It has also been recognized that HT preserves thyroid function, thereby reducing the requirement of a lifelong need for hormone replacement therapy.^[18] As a result, it is essential to balance the potential benefits versus possible harms to define the optimal extent of initial treatment. So far, few studies have assessed both benefits and harms of either surgical procedure. Therefore, the present study aimed to evaluate the benefits and harms of HT, TT in patients with 1–4 cm DTC.

Table 1. Baseline characteristics of patients with 1–4 cm differentiated thyroid cancer according to surgical procedure ^a
Variables	Before matching			After matching
Variables	HT (n = 286)	TT (n = 509)	p Value	HT (n = 276)	TT (n = 276)	p Value
Age, median (IQR), y	37.0 (29.0–47.0)	42.0 (33.0–53.0)	<.001	37.0 (29.5–48.0)	38.0 (30.0–46.8)	.475
Sex (female)	219 (76.6)	397 (78.0)	.645	212 (76.8)	213 (77.2)	.919
Neck dissection	196 (68.5)	415 (81.5)	<.001	192 (69.6)	210 (76.1)	.085
Pathology
Papillary	248 (86.7)	479 (94.1)	<.001	241(87.3)	250 (90.6)	.222
Follicular	38 (13.3)	30 (5.9)		35 (12.7)	26 (9.4)
Tumour size, median (IQR), cm	1.8 (1.4–2.5)	1.8 (1.4–2.5)	.411	1.8 (1.4–2.5)	1.8(1.4–2.5)	.556
Multifocality	36 (12.6)	229 (45.0)	<.001	36 (13.0)	33 (12.0)	.699
Hashimoto's thyroiditis	91 (31.8)	167 (32.8)	.775	89 (32.2)	78 (28.3)	.308
Capsular invasion	156 (54.5)	310 (60.9)	.081	154(55.8)	162 (58.7)	.491
Vascular invasion	33 (11.5)	41 (8.1)	.105	31 (11.2)	24 (8.7)	.320
ETE	64 (22.4)	169 (33.2)	.001	64 (23.2)	71 (25.7)	.488
LN metastasis	121 (42.3)	285 (56.0)	<.001	119 (43.1)	139 (50.4)	.088
RAI therapy	2 (0.7)	271 (53.2)	<.001	2 (0.7)	121 (43.8)	<.001
Duration, median (IQR), m	53.8 (34.2–85.7)	55.8 (39.7–79.1)	.549	53.8 (34.1–85.4)	59.0 (41.0–79.9)	.181
Structural persistent/recurrent disease	10 (3.5)	30 (5.9)	.138	10 (3.6)	12 (4.3)	.663

Abbreviations: ETE, Extrathyroidal extension, HT, Hemithyroidectomy, IQR, Interquartile range.
LN, Lymph node, RAI, Radioactive iodine, TT, Total thyroidectomy.
^aData are presented as number (%) of patients unless otherwise indicated.

Table 2. Primary (recurrence) and secondary outcomes ^a
Treatment benefit outcomes	HT (n = 276)	TT (n = 276)	HR (95%CI)	p Value
Total recurrence	10 (3.6)	12.(4.3)	0.86.(0.37–2.00)	.733
Regional LN metastasis	9 (3.3)	10.(3.6)	0.94.(0.38–2.31)	.891
Distant organ metastasis^b	2 (0.7)	4.(1.4)	0.50.(0.09–2.73)	.423
Treatment harm outcomes	HT (n = 276)	TT.(n = 276)	OR (95%CI)	p Value
Reoperation	2.(0.7)	0.(0)	NA	NA
Complications	43.(15.6)	78.(28.3)	0.47.(0.31–0.71)	<.001
Neck haematoma	0.(0)	1.(0.3)	NA	NA
Hypoparathyroidism
Permanent	3.(1.1)	18.(6.5)	0.16.(0.05–0.54)	.003
Transient	12.(4.3)	28.(10.1)	0.36.(0.18–0.72)	.004
RLN palsy
Permanent	8.(2.9)	10.(3.6)	0.72.(0.27–1.96)	.562
Transient	20.(7.2)	22.(7.9)	0.89.(0.45–1.61)	.614
L-T4 therapy	227.(82.2)	276.(100)	0.44.(0.20–0.95)	.007

Abbreviations: CI, Confidence interval, HR, Hazard ratio, HT, Hemithyroidectomy, LN, Lymph node, L-T4, Levothyroxine, OR, Odds ratio, RLN, Recurrent laryngeal nerve, TT, Total thyroidectomy.
^aData are presented as number (%) of patients unless otherwise indicated.
^bDistant organ metastasis Includes lung, bone, brain and subcutaneous muscle tissue.

Table 3. Cox proportional hazard regression analysis for variables associated with structural persistent/recurrent disease
Variables	Univariate analysis (n = 795)		Multivariate analysis (n = 795)
Variables	HR (95% CI)	p value	HR (95% CI)	p value
Sex(male)	0.74 (0.33–1.68)	.473	0.59 (0.26–1.35)	.213
Age ≥55 years	0.94 (0.42–2.13)	.886	1.18 (0.51–2.75)	.698
Neck dissection	2.98 (1.06–8.39)	.038	1.25 (0.39–4.03)	.711
Tumour size(cm)	1.26 (0.84–1.90)	.273	1.23 (0.81–1.86)	.337
Multifocality	2.08 (1.12–3.87)	.021	1.91 (0.98–3.71)	.057
Capsular invasion	2.62 (1.25–5.51)	.011	1.55 (0.64–3.75)	327
Vascular invasion	1.42 (0.56–3.63)	.463	1.59 (0.61–4.16)	.341
ETE	2.63 (1.41–4.89)	.002	2.24 (1.20–4.18)	.011
LN metastasis	4.10 (1.89–8.90)	<.001	4.10 (1.89–8.90)	<.001
RAI therapy	1.44 (0.77–2.70)	.252	0.49 (0.23–1.05)	.065
HT	0.60 (0.29–1.23)	.160	0.68 (0.29–1.58)	.367
HT (after PSM)	0.86 (0.37–2.00)	.733	0.88 (0.30–2.58)	.818

Abbreviations: CI, Confidence interval, ETE, Extrathyroidal extension, HR, Hazard radio, HT, Hemithyroidectomy, LN, Lymph node, PSM, Propensity score matching, RAI, Radioactive iodine.

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Benefits and Harms of Hemithyroidectomy, Total or Near-Total Thyroidectomy in 1– 4 cm Differentiated Thyroid Cancer

Abstract and Introduction

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