While open thyroidectomy (OT) is advocated as the gold standard treatment for differentiated thyroid cancer, the contemporary use of robotic thyroidectomy (RT) is often controversial. Although RT combines the unique benefits of the surgical robot and remote access thyroidectomy, its applicability on cancer patients is challenged by the questionable oncological benefits and safety. This review aims to analyze the current literature evidence in comparing RT to OT on thyroid cancers for their perioperative and oncological outcomes. To date, no randomized controlled trial is available in comparing RT to OT. All published studies are nonrandomized or retrospective comparisons. Current data suggests that RT compares less favorably than OT for longer operative time, higher cost, and possibly inferior oncological control with lower number of central lymph nodes retrieved. In terms of morbidity, quality of life outcomes, and short-term recurrence rates, RT and OT are comparable. While conventional OT continues to be appropriate for most thyroid cancers, RT should better be continued by expert surgeons on selected patients who have low-risk thyroid cancers and have high expectations on cosmetic outcomes. Future research should embark on prospective randomized studies for unbiased comparisons. Long-term follow-up studies are also needed to evaluate outcomes on recurrence and survival.
Since the first introduction of endoscopic endocrine neck surgery in 1996 [
Despite the vast abundance of literature reports supporting the safety and effectiveness of robotic thyroidectomy (RT) [
There are three most commonly described RT approaches for thyroid cancers. They are gasless transaxillary approach (TA), bilateral axillobreast approach (BABA), and gasless unilateral axillobreast approach (GUAB). At present, RT is almost exclusively applied on differentiated thyroid cancers (DTC) alone [
In the literature, more than 25 studies had been published comparing the outcomes between RT and OT for differentiated thyroid cancers [
As consistently shown in 19 comparative studies [
The length of hospital stay was analyzed in 15 comparative studies [
In addition to pain in the neck, pain at remote wound sites and skin flaps are inherently associated with RT. Using different assessment scales, postoperative pain had been compared in 8 studies [
In the literature, there was no universal consensus in defining transient and permanent recurrent laryngeal nerve (RLN) injuries. Their quoted incidences in RT varied between 1–7% for transient injury and 0–2% for permanent injury (Table
Summary of recurrent laryngeal nerve injury in published studies.
First author/year | RT approach | Sample size (RT versus OT) | Definition of transient RLN injury | Rates of transient RLN injury (%) |
Definition of permanent RLN injury | Rates of permanent RLN injury (%) |
---|---|---|---|---|---|---|
Lee, 2013 [ |
TA | 62 : 66 | Not stated | 3.2 : 4.5 |
Not stated | 0 : 0 |
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Ryu, 2013 [ |
TA | 45 : 45 | — | NR | Not stated | 0 : 0 |
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Tae, 2012 [ |
GUAB | 75 : 226 | Vocal cord palsy on laryngoscopy with recovery within 6 months | 8.0 : 3.1 |
Vocal cord palsy on laryngoscopy failed to recover after 6 months | 0 : 0.4 |
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Lee, 2012 [ |
TA | 192 : 266 | Not stated | 2.6 : 0.4 |
Not stated | 6.8 : 0 |
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Kang, 2012 [ |
TA | 56 : 109 | Not stated | 3.6 : 2.8 |
Not stated | 0 : 0 |
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Lee, 2010 [ |
TA | 41 : 43 | Vocal cord palsy on laryngoscopy with recovery within 6 months | 2.4 : 0 |
Vocal cord palsy on laryngoscopy not recovered after 6 months | 0 : 0 |
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Tae, 2011 [ |
GUAB | 41 : 163 | Not stated | 2.4 : 2.5 |
Not stated | 0 : 0.6 |
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Kim, 2011 [ |
BABA | 69 : 138 | Vocal cord palsy on laryngoscopy not recovering within 6 months | 1.4 : 0.7 |
Failure of voice change to normalize after 6 months | 0 : 0 |
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Yi, 2013 [ |
TA | 98 : 423 | Not stated | 1.0 : 0.5 |
— | NR |
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Kim, 2015 [ |
BABA | 13 : 65 | Vocal cord palsy on laryngoscopy lasting for <6 months | 0 : 4.6 |
Vocal cord palsy on laryngoscopy lasting for >6 months | 0 : 3.1 |
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Kwak, 2015 [ |
BABA | 206 : 634 | Vocal cord palsy on stroboscopy from 2 weeks to 6 months | 0.9 : 0.5 |
— | NR |
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Noureldine, 2013 [ |
TA | 24 : 35 | Vocal cord palsy on laryngoscopy lasting for <6 months | 4.1 : 5.7 |
Vocal cord palsy on laryngoscopy persisting after 6 months | 0 : 0 |
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Lee, 2014 [ |
TA | 60 : 56 | Not stated | 5.0 : 0 |
— | NR |
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Tae, 2014 [ |
GUAB | 62 : 183 | Not stated | 6.5 : 2.2 |
Not stated | 0 : 0 |
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Lee, 2014 [ |
TA | 43 : 51 | Not stated | 2.3 : 0 |
— | NR |
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Kim, 2014 [ |
BABA | 123 : 392 | Vocal cord palsy persisted <6 months | 4.9 : 6.1 |
Vocal cord palsy persisted >6 months | 0 : 0.3 |
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Song, 2014 [ |
GUAB | 118 : 176 | Not stated | 0.8 : 2.8 |
Not stated | 0 : 0 |
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Lee, 2012 [ |
TA | 42 : 46 | Vocal fold motion impairment on videolaryngostroboscopy from 1 week to 3 months | 21.4 : 19.5 |
— | NR |
RT, robotic thyroidectomy; OT, open thyroidectomy; RLN, recurrent laryngeal nerve; TA, transaxillary approach; GUAB, gasless unilateral axillobreast approach; BABA, bilateral axillobreast approach;
The definitions of postoperative transient and permanent hypoparathyroidism also varied among different studies (Table
Summary of hypoparathyroidism in published studies.
First author/year | RT approach | Sample size |
Definition of transient hypoparathyroidism | Rates of transient hypoparathyroidism (%) |
Definition of permanent hypoparathyroidism | Rates of permanent hypoparathyroidism (%) |
---|---|---|---|---|---|---|
Lee, 2013 [ |
TA | 62 : 66 | Drop in PTH with recovery <6 months | 38.7 : 34.8 |
Drop in PTH with no recovery after 6 months | 0 : 0 |
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Ryu, 2013 [ |
TA | 45 : 45 | — | NR | Not stated | 0 : 0 |
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Tae, 2012 [ |
GUAB | 75 : 226 | PTH below normal limit but recovered within 6 months | 27.5 : 49.5 |
PTH below normal limit and persisted for >6 months | 0 : 1.8 |
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Lee, 2012 [ |
TA | 192 : 266 | Not stated | 44.4 : 40.0 |
Not stated | 0 : 3.0 |
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Kang, 2012 [ |
TA | 56 : 109 | Not stated | 48.2 : 45.9 |
Not stated | 0 : 0 |
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Lee, 2010 [ |
TA | 41 : 43 | Not stated | 19.2 : 15.3 |
Not stated | 0 : 0 |
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Tae, 2011 [ |
GUAB | 41 : 163 | Not stated | 20.0 : 30.1 |
Not stated | 0 : 4.2 |
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Aliyev, 2013 [ |
TA | 16 : 30 | Serum Ca <8 mg/dL for ≤2 weeks | 12 : 13 |
— | NR |
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Kim, 2011 [ |
BABA | 69 : 138 | Normalization of PTH within 6 months | 33.3 : 27.5 |
Failure of normalization of PTH after 6 months | 1.4 : 2.9 |
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Yi, 2013 [ |
TA | 98 : 423 | Symptomatic and/or serum Ca <7.5 mg/dL for ≤6 months | 53.1 : 43.0 |
Symptomatic and/or serum Ca <7.5 mg/dL for >6 months | 3.1 : 0.7 |
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Kim, 2015 [ |
BABA | 13 : 65 | Serum ionized Ca <4.0 mEq/L or symptoms requiring Ca replacement | 0 : 15.4 |
Not stated | 0 : 1.5 |
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Kwak, 2015 [ |
BABA | 206 : 634 | Serum ionized Ca <4.4 mg/dL or PTH <8 pg/mL within 1 year | 15 : 14.6 |
Serum ionized Ca <4.4 mg/dL or PTH <8 pg/mL persisted after 1 year and need of Ca supplement | 0.3 : 0.5 |
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Noureldine, 2013 [ |
TA | 24 : 35 | Abnormal Ca level persisted <6 months | 8.3 : 11.4 |
Abnormal Ca level persisted >6 months | 0 : 0 |
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Lee, 2014 [ |
TA | 60 : 56 | Not stated | 42 : 45 |
— | NR |
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Tae, 2014 [ |
GUAB | 62 : 183 | Not stated | 43.5 : 37.1 |
Not stated | 1.6 : 1.6 |
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Lee, 2014 [ |
TA | 43 : 51 | Not stated | 46.5 : 31.4 |
— | NR |
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Kim, 2014 [ |
BABA | 123 : 392 | Low PTH within 6 months | 23.4 : 22.0 |
Low PTH persisted for >6 months | 0 : 0 |
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Song, 2014 [ |
GUAB | 118 : 176 | Not stated | 35.7 : 55.9 |
Not stated | 0 : 0.7 |
RT, robotic thyroidectomy; OT, open thyroidectomy; TA, transaxillary approach; GUAB, gasless unilateral axillobreast approach; BABA, bilateral axillobreast approach; PTH, parathyroid hormone; Ca, calcium;
Although bleeding and hematoma are the major lethal complications of thyroidectomy, the reported incidences in RT remained below 2-3% and were comparable with those of OT in 16 studies [
According to the results from the latest meta-analyses, the outcomes of RT and OT were comparable for the rates of seroma formation [
Postoperative voice change independent of RLN injury had been compared in 5 studies [
In three studies evaluating the subjective swallowing dysfunction, RT was shown to have significantly less dysfunction than OT in two studies [
Due to more extensive skin flap dissection, chest paresthesia was significantly more common after RT than OT in both TA and BABA techniques [
Cosmetic superiority was considered to be the most concerned advantage of RT. In all 6 studies comparing cosmetic satisfaction between RT and OT at different time-points from postoperative 1 day to 6 months, RT was associated with significantly higher cosmetic satisfaction scores irrespective of the operative approaches [
One of the greatest disadvantages of RT is cost. Based on a cost model consisting of operating room charges, anesthesia fee, consumable cost, equipment depreciation, and maintenance cost, Cabot et al. found that RT was 1.5 times more expensive than OT (USD
Radical central compartment nodal dissection (CCD) often represents the hallmark of favorable oncological control. In 15 studies comparing the number of LN retrieved during CCD [
Summary of oncological outcomes in published studies.
First author/year | RT approach | Sample size |
Mean number of |
Mean ablation |
---|---|---|---|---|
Lee, 2013 [ |
TA | 62 : 66 | 8.1 : 7.9 |
NR |
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Ryu, 2013 [ |
TA | 45 : 45 | 5.7 : 7.0 |
NR |
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Tae, 2012 [ |
GUAB | 75 : 226 | 4.4 : 7.7 |
12.7 : 4.9 |
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Lee, 2012 [ |
TA | 192 : 266 | 4.6 : 5.7 |
NR |
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Kang, 2012 [ |
TA | 56 : 109 | 6.5 : 8.6 |
NR |
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Lee, 2010 [ |
TA | 41 : 43 | 4.4 : 4.3 |
NR |
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Tae, 2011 [ |
GUAB | 41 : 163 | 4.7 : 9.6 |
NR |
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Kim, 2011 [ |
BABA | 69 : 138 | 4.7 : 4.8 |
0.8 : 0.8 |
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Yi, 2013 [ |
TA | 98 : 423 |
6.5 : 7.0 |
26% : 10.6% |
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Kim, 2015 [ |
BABA | 13 : 65 | 12.8 : 12.7 |
2.5 : 2.8 |
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Kwak, 2015 [ |
BABA | 206 : 634 | 5.8 : 8.4 |
NR |
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Lee, 2014 [ |
TA | 60 : 56 | NR | 5.3 : 1.6 |
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Tae, 2014 [ |
GUAB | 62 : 183 | 4.1 : 5.4 |
10.2 : 3.8 |
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Lee, 2014 [ |
TA | 43 : 51 | 4.9 : 6.3 |
4.4 : 4.1 |
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Kim, 2014 [ |
BABA | 123 : 392 | 8.7 : 10.4 |
1.3 : 1.1 |
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Lee, 2015 [ |
TA | 206 : 206 | 5.8 : 6.6 |
NR |
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Lee, 2011 [ |
BABA | 174 : 237 | NR | 1.4 : 1.2 |
RT, robotic thyroidectomy; OT, open thyroidectomy; LN, lymph nodes; sTg, thyrotropin-stimulated serum thyroglobulin; TA, transaxillary approach; GUAB, gasless unilateral axillobreast approach; BABA, bilateral axillobreast approach;
In thyroid cancer, surgical completeness of resection is commonly estimated by the serum thyroglobulin (Tg) levels and the RAI uptake levels on posttherapy whole-body scan (RxWBS) at radioiodine (RAI) ablation. The thyrotropin- (TSH-) stimulated Tg (sTg) level is a reliable surrogate marker for the amount of remnant thyroid tissue after total thyroidectomy. It is measured upon TSH stimulation by either thyroid hormone withdrawal or human recombinant TSH stimulation. Ablation sTg is measured at the time of RAI ablation while control sTg is measured at 6–12 months after RAI. In the literature, ablation sTg levels were reported to be significantly higher in RT than in OT in 4 studies [
Short-term locoregional recurrence within the first two postoperative years was comparable between RT and OT in 7 studies [
In the literature, the survival outcomes between RT and OT were only compared in one study [
As stated before, almost all the available evidences about the use of RT on thyroid cancer were originated from South Korea. The generalizability of these results to the North American or European populations is questionable because of the differences in body habitus, incidence of subcentimeter nodules, prevalence of obesity, and occurrence of thyroiditis in different ethnic groups [
Despite the established advantages on cosmesis, current data suggests that RT compares less favorably than OT for longer operative time, higher cost, and possibly inferior oncological control with lower number of central LN retrieved. In terms of morbidity and quality of life outcomes, RT and OT are comparable for thyroid cancer patients. While conventional OT continues to be appropriate for most thyroid cancer patients, RT should better be continued by expert surgeons on selected patients who have low-risk thyroid cancers and have high expectations on cosmetic outcomes. More prospective long-term follow-up studies are needed to define the oncological safety of RT.
All authors declare that there is no conflict of interests regarding the publication of this paper.