META-ANALYSIS
Hui-Min Guo, Xiao-Qi Zhang, Min Chen, Shu-Ling Huang, Xiao-Ping Zou, Department of Gastroenterology, the Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing 210008, Jiangsu Province, China
Author contributions: Guo HM and Zou XP designed the re
-search; Chen M and Huang SL completed the literature -search; Guo HM, Zhang XQ and Chen M analyzed the data; Guo HM and Zhang XQ wrote the paper.
Correspondence to:Xiao-Ping Zou, PhD,Department of
Gastroenterology, the Affiliated Drum Tower Hospital of Nan
-jing University Medical School, 321 Zhongshan Road, Nan-jing 210008, Jiangsu Province, China. zouxiaoping795@hotmail.com Telephone:+86-25-83106666 Fax: +86-25-83105321 Received:August 26, 2013 Revised:December 13, 2013 Accepted:January 19, 2014
Published online: May 14, 2014
Abstract
AIM: To investigate the effectiveness of endoscopic submucosal dissection (ESD) and endoscopic mucosal resection (EMR) in treating superficial esophageal can -cer (SEC).
METHODS: Studies investigating the safety and ef-ficacy of ESD and EMR for SEC were searched from the databases of Pubmed, Web of Science, EMBASE and the Cochrane Library. Primary end points included the en bloc resection rate and the curative resection rate. Secondary end points included operative time, rates of perforation, postoperative esophageal stricture, bleed-ing and local recurrence. The random-effect model and the fixed-effect model were used for statistical analysis. RESULTS: Eight studies were identified and included in the meta-analysis. As shown by the pooled analy -sis, ESD had significantly higher en bloc and curative resection rates than EMR. Local recurrence rate in the ESD group was remarkably lower than that in the EMR group. However, operative time and perforation rate for ESD were significantly higher than those for EMR.
As for the rate of postoperative esophageal stricture and procedure-related bleeding, no significant differ -ence was found between the two techniques.
CONCLUSION: ESD seems superior to EMR in the treatment of SEC as evidenced by significantly higher en bloc and curative resection rates and by obviously lower local recurrence rate.
© 2014 Baishideng Publishing Group Co., Limited. All rights reserved.
Key words: Superficial esophageal cancer; Endoscopic mucosal resection; Endoscopic submucosal dissection; Meta-analysis
Core tip: This meta-analysis was performed on the basis of previously published reports aiming to com-pare endoscopic submucosal dissection (ESD) with endoscopic mucosal resection (EMR) in treating super-ficial esophageal cancer. Eight studies involving 1081 patients were analyzed. Of those, 448 lesions were treated by ESD and 744 were treated by EMR. Com -pared with EMR, ESD had significantly higher overall en bloc and curative resection rates, and lower local recurrence rate. There was no significant difference in the complication rate between the two methods. Guo HM, Zhang XQ, Chen M, Huang SL, Zou XP.Endoscopic submucosal dissection vsendoscopic mucosal resection for superficial esophageal cancer. World J Gastroenterol 2014; 20(18): 5540-5547 Available from: URL: http://www.wjgnet. com/1007-9327/full/v20/i18/5540.htm DOI: http://dx.doi. org/10.3748/wjg.v20.i18.5540
INTRODUCTION
Nowadays superficial esophageal cancer (SEC) is in-creasingly detected with the innovation of endoscopy doi:10.3748/wjg.v20.i18.5540 © 2014 Baishideng Publishing Group Co., Limited. All rights reserved.
Endoscopic submucosal dissection
vs
endoscopic mucosal
resection for superficial esophageal cancer
Hui-Min Guo, Xiao-Qi Zhang, Min Chen, Shu-Ling Huang, Xiao-Ping Zoutechniques. Before the advent of endoscopic therapy, radical esophagectomy served as a standard therapeutic strategy for SEC, which was however reported to be related with high mortality and impaired quality of life (QOL)[1,2]. Later, the technique of endoscopic mucosal
resection (EMR) initiated a new era of endoscopic treat-ment for SEC[3]. To date, EMR has been widely applied
in clinical practice due to less invasion, lower cost, more patient tolerance, and better postoperative QOL. Never-theless, when applying EMR techniques to large lesion, it is always difficult to evaluate the margin of specimen by histopathology or to determine the risk of lymph node metastasis. In addition, EMR was reported to have high local recurrence rates after piecemeal resection[4].
In 1990s, endoscopic submucosal dissection (ESD) was developed to remove large lesions in the alimentary tract, thus providing en bloc specimens for adequate pathological evaluation of lateral and deep margins[5].
Us-ing improved needle-knife, the technique of ESD makes it possible to dissect the tumors from the submucosal layer. However, some studies showed that ESD could have a higher rate of complications, such as bleeding, perforation and postoperative esophageal stricture result-ing from complicated procedures[6]. To date, several
stud-ies[7-11] have compared the technique of ESD with EMR
for the treatment of SEC in terms of safety and efficacy, while the results of these studies were confounding when pooled together. To our knowledge, there was still a lack of a systematic review that specifically compares the safety and efficacy of ESD and EMR in the treatment of SEC. Aiming to provide a clinical basis for endoscopic treatment of SEC, this meta-analysis included several retrospective studies that evaluated the efficacy and safety of ESD and EMR in patients with SEC.
MATERIALS AND METHODS
Search strategy
To identify all relevant studies that compared ESD with EMR from 1995 to October 31, 2012, a systematical lit-erature search was performed through the databases of Pubmed, Web of Science, EMBASE, and the Cochrane Library with the language restricted to English. The fol-lowing search terms were used: “ESD”, “EMR”, “endo-scopic submucosal dissection”, “endo“endo-scopic mucosal re-section”, “esophageal” and “esophagus”. The references listed in the retrieved articles were screened manually.
Selections of studies
The studies were included in our meta-analysis accord-ing to the followaccord-ing criteria: (1) enrollaccord-ing patients diag-nosed with SEC by histology test; (2) comparing ESD and EMR for the treatment of SEC; (3) reporting the endpoints regarding therapeutic effect and complica-tions; and (4) having the sample size of more than ten. In case of duplicated reports, the one with more cases was selected. Any comment, review, or guideline articles without original data were excluded. Besides, studies
comparing ESD and EMR for lesions resulting from Barret’s esophagus were also excluded, as such lesions were mostly located in the gastroesophageal junction and the neoplasms were mostly adenoma.
Data extraction and study quality assessment
In this meta-analysis, primary end points included the rates of both en bloc and curative resections; secondary end points included surgical duration and rates of bleed-ing, perforation, postoperative esophageal stricture and local recurrence. In this study “en bloc” was defined as resection of the lesion in one piece without piecemeal, and “curative resection” was defined as resection with -out undifferentiated-type cell nests or lymphvascular in-vasion that could be detected by histopathology in both lateral and vertical margins. Surgical duration was defined as the time from marking to resection of the lesions. Bleeding was defined as the blood loss during surgical procedures. Perforation was diagnosed endoscopically when mediastinal connective tissue was observed during surgical procedures, or by the presence of free air on an imaginological examination. Postoperative stricture was defined as a stricture requiring endoscopic dilation. Lo -cal recurrence was defined as the same histology type of the neoplasm diagnosed by histology at the resection site during the follow-up of the patient.
Two investigators extracted detailed data indepen-dently and reached consensus by discussing possibly different opinions. The data were extracted from each literature including name of the first author, year of the publication, country of the study, the number of pa-tients and lesions, and duration of the follow-up.
The quality of each study was assessed according to the following six items: number of patients (more or fewer than ten patients); follow-up (more or less than 6 mo); comparable; comparison of operative procedures, ESD vs EMR; consecutive; and whether there was a clear protocol for the evaluation of surgical outcome. A qual-ity score was calculated for each study, with a maximum of six points indicating the best quality[12].
Statistical analysis
RevMan 5.0 software (Cochrane Collaboration) was used in this study. The forest plot can provide the summary data entered for each study including the weight for each study, the overall effect estimate, and the statistical significance of the analysis, while a summary receiver operating characteristic curve analysis can be used to select the optimal threshold under a variety of clinical circumstances, thereby showing an optimum cut-off for sensitivity and specificity. Since the primary purpose of current study was to compare the effectiveness of two different therapeutic methods for superficial esopha-geal cancer, the forest plot was applied for the statistical analysis. The weighted mean difference (WMD) was recommended for continuous data of surgical dura-tion, and the ORs with 95%CIs were recommended for dichotomous data, such as en bloc resection, curative
Table 1 Details of included studies (mean ± SD)
resection, local recurrence, perforation, and stricture. In the meta-analyses, we estimated heterogeneity with Chi-square and I2. P values < 0.1 or I2 more than 50% were
considered significantly heterogeneous[13]. Pooled data
were calculated using a fixed-effects model when there was no heterogeneity; or a random-effects model would be applied instead. Software Stata 11 (Stata Corporation, College Station, TX, United States) was used to detect publication bias, and then the symmetry of the funnel plot was confirmed by Egger’s test with a P value less than 0.05[14].
RESULTS
Study inclusion and assessment
A total of 145 studies were initially yielded using the above-mentioned search strategy. According to inclu-sion/exclusion criteria, eight reports were finally includ -ed in our meta-analysis[7-11,15-17]. The procedure of study
selection was shown in Figure 1. Overall, a total of 1080 patients with SEC were enrolled in the selected eight studies, which contained 448 lesions in the ESD group and 744 lesions in the EMR group. The main charac-teristics and quality assessment of the finally included reports are shown in Table 1.
En bloc resection rate
The en bloc resection rate was reported in eight pa-pers[7-11,15-17]. Since there was no heterogeneity among
these studies (P = 0.26; I2 = 22%), a fixed-effect model
was applied, and the overall analysis showed a signifi-cantly higher en bloc resection rate (97.1%; 435/448) in the ESD group than in the EMR group (49.3%; 367/744) irrespective of the diameter of the lesion (OR = 52.76; 95%CI: 25.57-108.84; P < 0.001) (Figure 2A). Four studies[7,8,11,16] subgrouped the patients according to
tumor size with the cut-off point set at 20 mm. In both subgroups, the en bloc resection rates were significantly
Potentially relevants studies
identified through search strategy
(n = 145)
Studies included in meta-analysis (n = 8)
Studied retrieved for
more evaluation with full
text (n = 116)
Potentially appropriate studies for inclusion in meta-analysis
(n = 9)
Mixed comparison excluded (n = 1)
Excluded by inclusion/exclusion (n = 107)
Duplicated studies excluded (n = 29)
Figure 1 process of article screening.
Ref. Country Full text/Abstract Patient n (ESD/EMR) Lesion n (ESD/EMR) Quality score Follow-up (mo)
Ishihara et al[11] 2008 Japan Full Text 148 (29/119) 171 (31/140) 5 Not recorded
Jung et al[15] 2008 South Korea Abstract 62 (34/28) 69 (37/32) 4 Not recorded
Kubota et al[16] 2010 Japan Abstract 165 (129/36) 167 (36/131) 5 ESD 29.8
EMR 64.0
Takahashi et al[10] 2010 Japan Full Text 300 (116/184) 300 (116/184) 6 65 (8-174)
Teoh et al[9] 2010 China Full Text 28 (18/10) 35 (22/13) 5 22.20 ± 17.31
Urabe et al[7] 2011 Japan Full Text 122 (59/63) 162 (79/83) 6 ESD 18.9
EMR 30.7
Yamashita et al[8] 2011 Japan Full Text 112 127 (71/56) 6 39 (8-123)
Konishi et al[17] 2012 Japan Abstract 143 (93/50) 161 (56/105) 5 ESD 15 (1-48)
EMR 70 (4-146) ESD: Endoscopic submucosal dissection; EMR: Endoscopic mucosal resection.
higher in the ESD group than in the EMR group (OR = 14.99; 95%CI: 3.30-68.03; P = 0.0005, OR = 115.88; 95%CI: 23.35-575.12; P < 0.00001, respectively).
Curative resection rate
Seven studies[7-11,15,16] provided the data of curative
resec-tion rate for SEC. There was significant heterogeneity among these studies (P = 0.02; I2 = 71%), therefore a
random-effect model was applied to perform the analy-sis, which showed a higher curative resection rate in the ESD group (92.3%; 362/392) than in the EMR group (52.7%; 337/639) (OR = 13.9; 95%CI: 4.84-39.95; P
< 0.001) (Figure 2B). On the basis of the result of the sensitivity analysis, one study[9] that might bias the result
was excluded. The result of remaining data still showed a higher curative resection rate in the ESD group (OR = 20.17; 95%CI: 8.30-49.05; P < 0.00001), and the hetero-geneity could be partially explained (P = 0.05; I2 = 56%). Surgical duration
Five involved studies[7,8,10,11,17] reported the comparison
of surgical duration between the ESD group and EMR group. A random-effect model was applied since there was heterogeneity among the studies (P < 0.00001; I2 =
96%). The result demonstrated that significantly longer surgical duration was needed in the ESD group than in the EMR group (WMD = 44.72; 95%CI: 18.46-70.98; P
= 0.0008) (Figure 3).
ESD EMR Odds ratio Odds ratio
Study or subgroup Events Total Events Total Weight M-H, fixed, 95%CI M-H, fixed, 95%CI Ishihara 2008 31 31 110 140 13.9% 17.39 [1.03, 292.42] Jung 2008 36 37 12 32 7.6% 60.00 [7.26, 495.86] Konishi 2012 56 56 53 105 7.1% 110.89 [6.68, 1841.77] Kubota 2010 29 36 3 131 5.5% 176.76 [43.10, 724.94] Takahashi 2010 116 116 98 184 7.1% 204.61 [12.53, 3340.41] Teoh 2010 21 22 9 13 11.2% 9.33 [0.91, 95.57] Urabe 2011 77 79 57 83 30.6% 17.56 [4.00, 77.03] Yamashita 2011 69 71 25 56 17.1% 42.78 [9.53, 191.98] Total (95%CI) 448 744 100.0% 52.76 [25.57, 108.84] Total events 435 367 Heterogeneity: χ2 = 8.93, df = 7 (P = 0.26); I2 = 22%
Test for overall effect: Z = 10.73 (P < 0.00001) 0.01 0.1 1 10 100Favours EMR Favours ESD
ESD EMR Odds ratio Odds ratio
Study or subgroup Events Total Events Total Weight M-H, fixed, 95%CI M-H, fixed, 95%CI Ishihara 2008 30 31 81 140 11.7% 21.85 [2.90, 164.79] Jung 2008 32 37 17 32 16.3% 5.65 [1.75, 18.21] Kubota 2010 23 36 2 131 14.2% 114.12 [24.14, 539.48] Takahashi 2010 113 116 144 184 16.2% 10.46 [3.16, 34.70] Teoh 2010 18 22 11 13 12.5% 0.82 [0.13, 5.23] Urabe 2011 77 79 57 83 14.6% 17.56 [4.00, 77.03] Yamashita 2011 69 71 25 56 14.5% 42.78 [9.53, 191.98] Total (95%CI) 392 639 100.0% 13.90 [4.84, 39.95] Total events 362 337 Heterogeneity: Tau2 = 1.42; χ2 = 20.96, df = 6 (P = 0.002); I2 = 71%
Test for overall effect: Z = 4.89 (P < 0.00001)
Favours EMR Favours ESD 0.005 0.1 1 10 200
A
B
Figure 2 Comparison of en bloc resection (A) and curative rates (B) between endoscopic submucosal dissection and endoscopic mucosal resection. ESD: Endoscopic submucosal dissection; EMR: Endoscopic mucosal resection.
ESD EMR Mean difference Mean difference Study or subgroup Mean SD Total Mean SD Total Weight Ⅳ, random, 95%CI Ⅳ, random, 95%CI Takahashi 2010 73.6 45.8 116 44.4 32.6 184 33.3% 29.50 [19.93, 39.07]
Urabe 2011 49.7 3.3 79 19.1 6.1 83 33.9% 30.60 [23.21, 37.99] Yamashita 2011 88.5 46.6 71 13.7 10.3 56 32.8% 74.80 [63.63, 85.97] Total (95%CI) 266 323 100.0% 44.72 [18.46, 70.98]
Heterogeneity: Tau2 = 515.11; χ2 = 48.11, df = 2 (P < 0.00001); I2 = 96%
Test for overall effect: Z = 3.34 (P = 0.0008) -100 -50 0 50 100Favours ESD Favours EMR
Figure 3 Forest plot showing the procedural time for endoscopic submucosal dissection and endoscopic mucosal resection. ESD: Endoscopic submucosal dissection; EMR: Endoscopic mucosal resection.
Comparison of complications
Perforation rate: All the included studies[7-11,15-17]
report-ed the data of procreport-edure-relatreport-ed perforation. A fixreport-ed- fixed-effect model was applied as there was no heterogeneity among the studies (P = 0.26; I2 = 21%). The pooled
analysis demonstrated that the perforation rate for ESD was higher than that for EMR (OR = 2.19; 95%CI: 1.08-4.47; P = 0.03) (Figure 4A).
Postoperative esophageal stricture: Six studies[7-11,15]
re-ported the data of postoperative esophageal stricture. A fixed-effect model was applied as there was no hetero -geneity (P = 0.24; I2 = 26%). The overall result
demon-strated that there was no significant difference between the ESD group and the EMR group concerning the esophageal stricture rate (OR = 1.14; 95%CI: 0.71-1.84;
P = 0.59) (Figure 4B).
Bleeding rate: Five studies[7,9,11,15,16] reported
operation-related bleeding. There was no heterogeneity (P = 0.70;
I2 = 0%) among the studies, thereby a fixed-effect model
was applied. No statistical difference was noted in terms of bleeding rates between the two groups (OR = 0.74; 95%CI: 0.20-2.74; P = 0.65) (Figure 4C).
Recurrence rate: Seven studies[7-11,15,17] reported the data
of local recurrence. The pooled analysis showed a sig-nificantly lower recurrence rate in the ESD group (0.3%; 1/398) than in the EMR group (11.5%; 80/695) (OR = 0.08; 95%CI: 0.03-0.23; P < 0. 001). As there was no heterogeneity among the studies (P = 0.80; I2 = 0%), a
fixed-effect model was applied (Figure 5). However, sub -group analysis showed that the recurrence rate for ESD was not higher than that for EMR when lesion size was smaller than 20 mm (OR = 0.34; 95%CI: 0.06-2.08; P
ESD EMR Odds ratio Odds ratio
Study or subgroup Events Total Events Total Weight M-H, fixed, 95%CI M-H, fixed, 95%CI Ishihara 2008 1 31 0 140 1.7% 13.82 [0.55, 347.43] Jung 2008 1 37 0 32 4.9% 2.67 [0.11, 67.89] Konishi 2012 3 56 0 105 3.1% 13.80 [0.70, 272.14] Kubota 2010 2 36 1 131 3.9% 7.65 [0.67, 86.86] Takahashi 2010 3 116 3 184 21.6% 1.60 [0.32, 8.07] Teoh 2010 1 22 0 13 5.5% 1.88 [0.07, 49.67] Urabe 2011 6 79 2 83 17.2% 3.33 [0.65, 17.01] Yamashita 2011 1 71 4 56 42.1% 0.19 [0.02, 1.71] Total (95%CI) 448 744 100.0% 2.19 [1.08, 4.47] Total events 18 10 Heterogeneity: χ2 = 8.90, df = 7 (P = 0.26); I2 = 21%
Test for overall effect: Z = 2.16 (P = 0.03)
ESD EMR Odds ratio Odds ratio
Study or subgroup Events Total Events Total Weight M-H, fixed, 95%CI M-H, fixed, 95%CI Ishihara 2008 0 31 3 140 4.1% 0.62 [0.03, 12.38] Jung 2008 3 37 3 32 9.5% 0.85 [0.16, 4.55] Takahashi 2010 20 116 17 184 34.8% 2.05 [1.02, 4.09] Teoh 2010 2 22 0 13 1.8% 3.29 [0.15, 74.06] Urabe 2011 4 79 8 83 23.7% 0.50 [0.14, 1.73] Yamashita 2011 6 71 8 56 26.2% 0.55 [0.18, 1.70] Total (95%CI) 356 508 100.0% 1.14 [0.71, 1.84] Total events 35 39 Heterogeneity: χ2 = 6.73, df = 5 (P = 0.24); I2 = 26%
Test for overall effect: Z = 0.54 (P = 0.59)
ESD EMR Odds ratio Odds ratio
Study or subgroup Events Total Events Total Weight M-H, fixed, 95%CI M-H, fixed, 95%CI Ishihara 2008 0 31 1 140 10.3% 1.48 [0.06, 37.09]
Jung 2008 2 37 1 32 19.1% 1.77 [0.15, 20.50] Kubota 2010 0 36 0 131 Not estimable Teoh 2010 0 22 1 13 34.4% 0.19 [0.01, 4.89]
Urabe 2011 1 79 2 83 36.3% 0.52 [0.05, 5.84] Total (95%CI) 205 399 100.0% 0.74 [0.20, 2.74] Total events 3 5
Heterogeneity: χ2 = 1.43, df = 3 (P = 0.70); I2 = 0%
Test for overall effect: Z = 0.45 (P = 0.65)
A
B
C
Figure 4 Incidence of perforation (A), stricture (B) and bleeding (C) between endoscopic submucosal dissection and endoscopic mucosal resection. ESD: Endoscopic submucosal dissection; EMR: Endoscopic mucosal resection.
0.01 0.1 1 10 100
Favours ESD Favours EMR 0.01 0.1 1 10 100
Favours ESD Favours EMR
Favours ESD Favours EMR 0.01 0.1 1 10 100
= 0.25), and there was no heterogeneity (P = 0.77; I2 =
0%). The result was not influenced when lesion size was larger than 20 mm (OR = 0.05; 95%CI: 0.01-0.28; P = 0.0006), and no heterogeneity was found among studies (P = 0.82; I2 = 0%).
Publication bias: No publication bias was detected by
funnel plot and the Egger test when the data of en bloc resection and perforation were used as the outcome (P = 0.792 and 0.413, respectively).
DISCUSSION
Compared with traditional surgery, endoscopic therapy was widely accepted due to less invasion and better QOL of patients after removal of mucosal lesions[18], which
could ideally facilitate en bloc and curative resection and reduce the risk of local recurrence[11]. The current study
confirmed a distinct advantage of ESD over EMR in terms of clinical effectiveness. The en bloc resection rate in the ESD group was significantly higher than that in the EMR group, which was consistent with the previous meta-analysis studies[19,20] on the efficacy and safety of
ESD and EMR in early gastric cancer and rectal carci-noid tumours. Considering that ESD was more applied to the lesion larger than 20 mm, we did subgroup analy-ses that demonstrated the same superiority of ESD in the en bloc resection for SEC than EMR regardless of the lesion size[11].
Compared with piecemeal resection, en bloc resec-tion could be more effective to achieve an entire patho-logic specimen and provide precise histopathopatho-logic assessment, making it possible to raise the curative re-section rate for SEC[21]. In our study, the pooled result
showed that the curative resection rate was higher in the ESD group than in the EMR group. Considering that endoscopist teams in Japan and South Korea could be more experienced, we did a sensitivity analysis after ex-cluding one study from Hongkong which has quite dif-ferent result from that of other studies. The sensitivity analysis still showed a superior curative resection rate in the ESD group than in the EMR group. Along with the high curative rate for SEC in the ESD group, the pooled
analysis showed the local recurrence rate in the ESD group was much lower than that in the EMR group. The subsequent subgroup analysis demonstrated that this advantage was only observed when lesion size was larger than 20 mm.
ESD is composed of a series of complicated pro-cedures[22], and some authors reported that some
pro-cedure-related complications can remarkably prolong the surgical duration. In this study, the pooled analysis showed that surgical duration in the ESD group was significantly longer than that in the EMR group. Nev -ertheless, with the accumulation of surgical experience of endoscopists, the procedure time for ESD may be reduced[23].
Although showing great advantages in terms of en bloc resection rates, curative resection rates, and local re-currence rates, ESD was found to have a higher rate of perforation in our study. Perforation is a common and serious complication of endoscopic treatment, which might be associated with lesion size and the depth of invasion[24]. Another serious complication related to the
procedure of ESD is postoperative esophageal stricture, which might lead to severe dysphagia and decrease the QOL of the patient[25]. However, the pooled data of our
study showed that the rate of stricture in the ESD group was comparable with that in the EMR group. From data of studies reporting the rate of esophageal stricture, we found that stricture mostly occurred in patients with large lesions, reflecting the fact that lesion resection in such patients can inevitably result in cicatricial stenosis since the mucosal defects always exceeded three-fourths of the circumference[10].
Several limitations existed in our study. Similar to earlier meta-analysis on endoscopic methods, the current study included a limited number of studies that were currently available. Inevitably, there was heterogeneity in the quality of the studies, such as the definitions of complication were not unified across the studies. Finally, the results of our analysis was dominated by studies from Asian population, therefore the conclusions may not be applicable to patients in other populations.
ESD showed considerable advantages regarding the en bloc resection rate, curative resection rate, and local
ESD EMR Odds ratio Odds ratio
Study or subgroup Events Total Events Total Weight M-H, fixed, 95%CI M-H, fixed, 95%CI Ishihara 2008 0 31 2 140 1.7% 0.88 [0.04, 18.77] Konishi 2012 0 56 9 105 12.7% 0.09 [0.01, 1.57] Kubota 2010 0 36 40 131 33.6% 0.03 [0.00, 0.52] Takahashi 2010 1 116 18 184 26.5% 0.08 [0.01, 0.61] Teoh 2010 0 22 1 13 3.5% 0.19 [0.01, 4.89] Urabe 2011 0 66 6 66 12.4% 0.07 [0.00, 1.27] Yamashita 2011 0 71 4 56 9.6% 0.08 [0.00, 1.55] Total (95%CI) 398 695 100.0% 0.08 [0.03, 0.23] Total events 1 80 Heterogeneity: χ2 = 3.03, df = 6 (P = 0.80); I2 = 0%
Test for overall effect: Z = 4.78 (P < 0.00001) 0.01 0.1 1 10 100Favours ESD Favours EMR Figure 5 Comparison of recurrence rate between endoscopic submucosal dissection and endoscopic mucosal resection. ESD: Endoscopic submucosal dis-section; EMR: Endoscopic mucosal resection.
recurrence rate when compared with EMR for SEC. Al-though there was a higher rate of perforation for ESD, the rates of esophageal stricture and bleeding for ESD in the treatment of SEC was similar to those for EMR. High quality and randomize-control trials from more countries with larger samples are warranted to validate these results. Compared with EMR, ESD had signifi-cantly higher en bloc and curative resection rates in the treatment of SEC, while its local recurrence rate was lower. A multicentre randomized controlled trial is war-ranted in order to acquire stronger evidence.
COMMENTS
Background
Nowadays superficial esophageal cancer (SEC) is increasingly detected with the innovation of endoscopy techniques. Both endoscopic submucosal dissec
-tion (ESD) and endoscopic mucosal resec-tion (EMR) can overcome the short
-coming of radical esophagectomy, and thus extensively used in the treatment of SEC.
Research frontiers
In earlier literature concerning the treatment of SEC, EMR was demonstrated to have advantages in terms of less invasion, lower cost, more patient tolerance, and better postoperative quality of life of patient, which was however reported to have high local recurrence rates after piecemeal resection. By contrast, ESD was found to yield lower local recurrence rate, which nevertheless could have higher rates of procedure-related bleeding, perforation and postoperative esophageal stricture. To date, several studies have compared the technique of ESD with EMR for the treatment of SEC in terms of safety and efficacy, while the results of these studies were confounding when pooled together.
Innovations and breakthroughs
This meta-analysis demonstrated that ESD is superior to EMR in the treatment of SEC as evidenced by significantly higher en bloc and curative resection rates and by obviously lower local recurrence rate.
Applications
This meta-analysis provided a clinical basis for endoscopic treatment of SEC. Terminology
Superficial esophageal cancer means the cancer confined to mucosal or sub
-mucosal layer of the esophagus, without lymph node metastasis. EMR and ESD are endoscopic therapy methods, which can remove the lesions of the alimentary tract without surgical procedures and have been extensively used in
clinical practice.
Peer review
This paper was performed to compare ESD and EMR in terms of safety and effectiveness when treating SEC, and it was concluded that ESD could be su
-perior to EMR in the treatment of SEC as evidenced by significantly higher en bloc and curative resection rates and by obviously lower local recurrence rate. The study is concise and informative.
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P- Reviewers: Shi HY, Snyder N
