Journal of Cancer Research and Therapeutics

ORIGINAL ARTICLE
Year
: 2016  |  Volume : 12  |  Issue : 2  |  Page : 550--555

Comparison between endoscopic thyroidectomy and conventional open thyroidectomy for papillary thyroid microcarcinoma: A meta-analysis


Yujie Li1, Xiaodong Zhou2,  
1 Department of Surgical Oncology, Ningbo No. 2 Hospital, Ningbo, China
2 Yuyao People's Hospital, Zhejiang Province, China

Correspondence Address:
Xiaodong Zhou
Department of Surgical Oncology, Ningbo No. 2 Hospital, Ningbo, Zhejiang Province
China

Abstract

Background: Endoscopic thyroidectomy (ET) has gained acceptance among surgeons as its feasibility has been well-documented. The aim of this systematic review with meta-analysis has been to assess and validate the safety and feasibility of ET when compared to conventional open thyroidectomy (COT) for papillary thyroid microcarcinoma (PTMC) and to verify other potential benefits and drawbacks. Materials and Methods: PubMed, Web of Knowledge are searched for studies concerning treatment for papillary thyroid microcarcinoma between 2000 and 2013, the method of meta-analysis is performed to compare the effect of different treatment. Result: Six studies with a total of 1081 patients were included. Primary outcomes include transient recurrent laryngeal nerve (RLN) palsy, permanent PLN palsy, transient hypocalcemia, permanent hypocalcemia, and overall recurrence. ET experienced a higher incidence of transient RLN palsy than COT. There were no statistically significant differences for the presence of permanent PLN palsy, transient hypocalcemia, and permanent hypocalcemia. Tumor recurrence was detected in the both group, but the difference was not statistically significant. Secondary outcomes include operative time, length of hospitalization, and cosmetic results. Patient satisfactory score significantly favored ET (mean difference [MD] = −1.64, 95% confidence interval [CI] [−1.85, −1.43], P < 0.00001). Operative time was significantly longer in ET (MD = 38.18, 95% CI [22.24, 54.11], P < 0.00001). The length of hospitalization was not significantly different in both groups (MD = −0.46, 95% CI = [−1.40, 0.47], P = 0.33). Conclusion: For PTMC, ET is a feasible, practical, and safe alternative with better cosmetic benefits, and it can be performed with an ease of manipulation that is similar to that of COT.



How to cite this article:
Li Y, Zhou X. Comparison between endoscopic thyroidectomy and conventional open thyroidectomy for papillary thyroid microcarcinoma: A meta-analysis.J Can Res Ther 2016;12:550-555


How to cite this URL:
Li Y, Zhou X. Comparison between endoscopic thyroidectomy and conventional open thyroidectomy for papillary thyroid microcarcinoma: A meta-analysis. J Can Res Ther [serial online] 2016 [cited 2020 Jul 5 ];12:550-555
Available from: http://www.cancerjournal.net/text.asp?2016/12/2/550/157353


Full Text



 Introduction



Endoscopic neck surgery for the thyroid was developed by Hüscher et al. in 1997.[1] Since then, various methods, including axillary, breast, and anterior chest approaches have been introduced by many surgeons.[2],[3],[4] The use of endoscopy for complete thyroidectomy has been viewed with concern, although many surgeons have regarded benign thyroid disease as an indication for endoscopic surgery.[5] In 2002, however, Miccoli et al. attempted to apply minimally invasive video-assisted thyroidectomy to resection of a papillary thyroid carcinoma.[6] Afterward, endoscopic thyroidectomy (ET) has gained the greatest acceptance among surgeons between endoscopic and video-assisted techniques, as its feasibility has been well-documented.[7],[8]

Till date, four meta-analyses have been performed to compare and summarize the results of ET with those of the conventional open thyroidectomy (COT).[9],[10],[11],[12] However, most included trials were compared for the benign lesion. The aim of this study has been to assess and validate the safety and feasibility of ET when compared to COT and to verify other potential benefits and drawbacks for papillary thyroid microcarcinoma (PTMC).

 Materials and Methods



Search strategy

PubMed, Web of Knowledge, The Net of Chinese Journal were searched from January 2000 to December 2013 without language restrictions. The search terms used were “ET,” “COT,” and “PTMC.” The reference lists of relevant studies were checked manually to locate any missing studies.

Study selection

Identified studies were assessed for eligibility for inclusion in the review by scrutinizing the titles, abstracts, and keywords of every record retrieved. Studies were restricted to those published in English and Chinese. Clinical studies concerning comparisons of any aspects between the ET and COT for PTMC were also included.

Data extraction

Two co-authors (LY and ZX) independently selected studies for inclusion and exclusion and reached consensus when they did not agree in the initial assignment. The following variables were recorded: Authors, journal and year of publication, number of patients, age, duration of operation, blood loss, visual analog scale for pain at 6, 24, and 48 h, score for cosmetic skin result, transient recurrent laryngeal nerve (RLN) palsy, permanent RLN palsy, transient hypocalcemia, and permanent hypocalcemia. If necessary, the corresponding authors of studies were contacted to obtain supplementary information.

Statistical analysis

A formal meta-analysis was made for all studies comparing the results of ET and COT for PTMC. The outcomes used for this study were perioperative variables (lymph nodes retrieved, duration of operation, duration of hospitalization), adverse events (transient RLN palsy, permanent RLN palsy, transient hypocalcemia and permanent hypocalcemia and recurrence), and skin cosmesis concerning the incision. Pooled estimates of outcomes were calculated using a fixed-effects model, but a randomized-effects model was used according to heterogeneity. The test of homogeneity of effects was performed using χ2 tests, with P ≤ 0.05 indicating significant heterogeneity. When the hypothesis of homogeneity was not rejected, the fixed-effects model was used to estimate the pooled effect of outcomes; when the reverse was true, the random effects model was also calculated. For dichotomous data, the results for each study were expressed as an odds ratio (OR) with 95% confidence intervals (CIs). For continuous outcomes, the effect size was measured as the weighted mean difference (MD) with 95% CIs. Bias was studied using sensitivity analysis by removing individual studies from the data set and analyzing the overall effect size and the weighted regression tests described by Egger et al.[13] For each total or subtotal the test for heterogeneity; the statistic I2 (measuring the extent of inconsistency among results and is interpreted as approximately the proportion of total variation in study estimates that is due to heterogeneity rather than sampling error) and the test for overall effect (Z statistic with P- value) is given. The Cochrane Collaboration's Review Manager Software (RevMan version 5.0, Cochrane collaboration) was used for the data analysis, and StatsDirect version 2.6.5 (StatsDirect, Cheshire, UK) for evaluating the potential publication bias.

 Results



Study selection

We identified 265 potentially relevant articles [Figure 1]. After exclusion of duplicate references, none-relevant literature, and those that did not satisfy inclusion criteria, 29 candidate articles were considered for the meta-analysis. After careful review of the full text of these articles, six studies were included. The study characteristics are summarized in [Table 1],[Table 2],[Table 3]. Patient demographics for the six studies are presented in [Table 1]. All papers were retrospective chart reviews. The publication dates ranged from 2000 to 2013. Study sizes ranged from 67 to 499 patients.{Figure 1}{Table 1}{Table 2}{Table 3}

Primary outcome measures

The RLN frequently lies on the thyroid at the site of the ligament of berry; just before the nerve enters the cricothyroid muscle, the RLN is vulnerable to injury in the area. Transient RLN palsy was observed in five studies, COT group had less transient RLN palsy [OR = 2.06, 95% CI (1.28, 3.31), P = 0.003; [Figure 2]. The prevalence of permanent RLN palsy was 0.72% in the ET group versus 0.63% in the COT group without significant difference [OR = 1.48, 95% CI (0.20–10.97), P = 0.70; [Figure 3]. Four studies assessed patients for transient hypocalcemia. The prevalence of transient hypocalcemia was 21.1% in the ET group versus 17.1% in the COT group. However, this difference was not statistically significant [OR = 1.27, 95% CI (0.50–3.21), P = 0.62; [Figure 4]. Two studies reported permanent hypocalcaemia, and there was no significant difference in the occurrence [OR = 0.28, 95% CI (.05–1.52), P = 0.14; [Figure 5]. The overall recurrence rate was lower in the ET group than in the COT group, but this difference was not statistically significant [OR = 0.36, 95% CI (0.10–1.30), P = 0.12; [Figure 6].{Figure 2}{Figure 3}{Figure 4}{Figure 5}{Figure 6}

Secondary outcome measures

The operative time was measured to the nearest minute from initiation of the incision to skin closure. The operation time [MD = 38.18, 95% CI (22.24, 54.11), P < 0.00001; [Figure 7] was significantly shorter in favor of COT. The length of hospitalization was not significantly different in both groups [MD = −0.46, 95% CI = (−1.40, 0.47), P = 0.33; [Figure 8].{Figure 7}{Figure 8}

Objective evaluation of cosmetic results is difficult at present. Cosmetic results are difficult to demonstrate without some bias because of the subjective judgment of the patients. Cosmetic results were evaluated with a scoring system (1: Extremely; 2: Fairly; 3: Normal; 4: Not at all) 6 months after the operation. Two of the six studies reported that patients in the ET group were more satisfied with the cosmetic results [MD = −1.64, 95% CI (−1.85, −1.43), P < 0.00001; [Figure 9].{Figure 9}

 Discussion



Thyroid disease usually occurs in women, and the incidence in young women is on the rise. At this time, patients are interested not only in the treatment of the disease, but also the postoperative quality of life, such as operative scarring, degree of pain, and the ability to rapidly return to work. These interests have focused on the cosmetic results and noninvasiveness of the surgery and resulted in the development of techniques of endoscopic surgery.

Endoscopic thyroid surgery is considered to be appropriate for benign thyroid disease. However, several reports about the application of ET for PTMC patients in the low-risk group have emerged. Kitano et al. reported that indications for ET in thyroid carcinoma are as follows: (1) Age <45 years, (2) tumor size <2 cm, and (3) no evidence of lymph node or local invasion.[4] Miccoli et al. showed that there was no difference between COT and ET in surgical completeness.[6]

The common complications of ET were transient/permanent hypocalcemia and transient/permanent RLN palsy. Randolph reported that the incidence of transient/permanent RLN palsy was 0–6% and <1%, respectively.[14] The incidence of transient/permanent hypocalcemia was 0.3–49% and 0–13%, respectively. Our meta-analysis showed that the ET was of similar efficacy with the COT. Though ET experienced a higher incidence of transient RLN palsy than COT, the patients with transient RLN palsy recovered within 2 months. We believed that transient RLN palsy was related to the thermal injury caused by the ultrasonic coagulation device. Tumor recurrence was detected in the both group, but the difference was not statistically significant.

Endoscopic thyroidectomy had a much better cosmetic result and smaller incision length, which was also one of its most obvious advantages; most of the patients could accept a 1.5 cm scar rather than a scar that measures not <5 cm for a thyroidectomy. A longer operative time was required in ET because the minimally invasive approach to the thyroid may increase the complexity of the operation. In addition, the learning curve also plays an important role. Surgeon's experience together with the evolution of the surgical instrumentation such as the introduction of the harmonic scalpel will significantly decrease the duration of the operative endoscopic time.[9] There were no significant differences in length of hospital stay between the two groups.

As described above, ET is an effective alternative for selected patients with PTMC compared with COT. Although we know that long-term follow-up and a more number of patients will be necessary, the ET outcomes in this study were favorable compared with COT.[20]

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