Endocuff-Assisted versus Cap-Assisted Colonoscopy Performed by Trainees: A Retrospective Study

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Clin Endosc. 2020;53(3):339-345

Publication date (electronic) : 2020 January 10

doi : https://doi.org/10.5946/ce.2019.124

Yutaka Okagawa, Tetsuya Sumiyoshi, Yusuke Tomita, Shutaro Oiwa, Fumihiro Ogata, Takashi Jin, Masahiro Yoshida, Ryoji Fujii, Takeyoshi Minagawa, Kohtaro Morita, Hideyuki Ihara, Michiaki Hirayama, Hitoshi Kondo

Department of Gastroenterology, Tonan Hospital, Sapporo, Hokkaido, Japan

Correspondence: Yutaka Okagawa Department of Gastroenterology, Tonan Hospital, North 4, West 7, Chuo-ku, Sapporo, Hokkaido 060-0004, Japan Tel: +81-11-231-2121, Fax: +81-13-762-2753, E-mail: yutaka.okagawa@tonan.gr.jp

Received 2019 June 24; Revised 2019 September 5; Accepted 2019 September 9.

Abstract

INTRODUCTION

Colorectal cancer is the second leading cause of cancer death worldwide, and its incidence is increasing [1]. The removal of colon adenomas reduces colorectal cancer-related deaths, so it is important that colon adenomas are not missed during routine colonoscopy [2,3]. A post-colonoscopy colorectal cancer (PCCRC) is a cancer detected after a negative screening colonoscopy, and the reported incidence of PCCRC is 6.0%–8.2% of all colorectal cancers [4,5]. Moreover, it has been reported that around half of PCCRCs result from undetected lesions [6]. Several reports have suggested that the adenoma detection rate (ADR) and mean number of adenomas detected per patient (MAP) are colonoscopy quality indicators because of their association with PCCRC [7,8]. Colonoscopy trainees—not only have a low cecal intubation rate but also are more likely to exhibit incomplete inspection of the colonic mucosa, leading to missed colon adenomas [9,10]. The use of a small plastic transparent cap attached to the tip of the colonoscope reportedly improved the cecal intubation rate and reduced the incidence of missed lesions [11-14]. Additionally, cap-assisted colonoscopy (CAC) was reportedly more effective for the detection of polyps by colonoscopy trainees [14]. Endocuff (Arc Medical Design Ltd., Leeds, England) is a new endoscopic cap made of a soft plastic material with two rows of flexible arms. This device stretches the colorectal lumen to enable enhanced viewing of the mucosa, resulting in fewer missed polyps hidden behind folds or in the corners of the colorectal lumen. The use of Endocuff in colonoscopy has been shown to improve the ADR compared to conventional colonoscopy (CC) [15-18]. Many studies have compared the efficacy of Endocuff-assisted colonoscopy (EAC) and CAC with CC; however, few studies have compared the usefulness of EAC and CAC. Recently, Sola-Vera et al. conducted a randomized study comparing EAC and CAC and concluded that there was no significant difference in ADR between the two groups [19]. However, the experience level of the endoscopist was not discussed in detail in that study; thus, differences between EAC and CAC in trainees remain controversial. Thus, the aim of the present study was to retrospectively compare the efficacy between EAC and CAC performed by trainees.

MATERIALS AND METHODS

RESULTS

Patient characteristics

A total of 305 patients underwent colonoscopy performed by three trainees between January and December 2018. Trainee A performed 94 colonoscopies in three months, trainee B performed 121 colonoscopies in four months, and trainee C performed 90 colonoscopies in three months. Of the 305 patients, 18 were excluded due to a history of colorectal surgery (n=15), a history of IBD (n=2), and inadequate bowel preparation (n=1). Therefore, 94 and 193 patients who underwent EAC and CAC, respectively, were included in the analysis (Fig. 1). Evaluation of the patients’ baseline characteristics showed no significant differences in age, sex, or indication for colonoscopy between the two groups (Table 1).

Fig. 1.

Flow diagram of patient selection for the study. CAC, cap-assisted colonoscopy; EAC, Endocuff-assisted colonoscopy; IBD, inflammatory bowel disease.

Table 1.

Patient Characteristics

Procedure-related outcomes

There was no significant difference in the cecal intubation rate of the trainees between the EAC and CAC groups (93.6% vs. 92.2%, p=0.849). In cases where the trainee failed cecal intubation, an expert instead performed the intubation phase, and cecal intubation was ultimately achieved in all patients. The mean intubation times of the trainees in the EAC and CAC groups were 7.50 and 8.38 min, respectively, and this difference was not significantly different (p=0.081). Similarly, there was no significant difference in the mean withdrawal time between the EAC and CAC groups (9.52 min vs. 9.63 min, p=0.167) (Table 2).

Table 2.

Colonoscopy Results

Polyp detection rate

A total of 365 polyps were endoscopically detected: 167 in the EAC group and 198 in the CAC group. The PDR was significantly higher in the EAC group than in the CAC group (66.0% vs. 51.8%, p=0.044). The mean number of polyps detected per patient was also higher in the EAC group (1.77 vs. 1.03, p=0.009). A total of 291 resected polyps (79.7% of all polyps) were examined pathologically; 128 polyps in the EAC group and 143 in the CAC group were diagnosed as adenomas. One advanced colon cancer was found in the EAC group. There were 27 and 47 unresected polyps in the EAC and CAC groups, respectively (Table 3).

Table 3.

Polyp Detection Rate and Adenoma Detection Rate

Adenoma detection rate

ADR was significantly higher in the EAC group than in the CAC group (54.3% vs. 37.3%, p=0.019). Although there was no significant difference in the ADR of each trainee between the two groups, it was higher in the EAC group than in the CAC group (trainee A, 55.9% vs. 38.5%, p=0.174; trainee B, 57.9% vs. 41.8%, p=0.159; trainee C, 50.0% vs. 30.6%, p=0.179) (Table 3). Although we used colonoscopes from two companies in this study, there was no significant difference in the rate of scope selection (Olympus vs. Fujifilm; EAC, 37.2% vs. 62.8%; CAC, 33.2% vs. 66.8%, p=0.559) or in ADR (Olympus vs. Fujifilm; EAC, 51.4% vs. 55.9%, p=0.716; CAC, 39.1% vs. 36.4%, p=0.766) between the two companies. The number of resected adenomas was 128 in the EAC group and 143 in the CAC group, and the MAP was significantly higher in the EAC group than in the CAC group (1.36 vs. 0.74, p=0.003). Moreover, MAP of all colon segments was higher in the EAC group and significantly higher in the sigmoid colon in this group (Table 4). There was no significant difference in the mean size of detected adenomas between the EAC and CAC groups (6.1 mm vs. 5.4 mm, p=0.088). Similarly, when detected adenoma size was classified as ≤5 mm, >5 to <10 mm, and ≥10 mm, there was no significant difference between the two groups. Additionally, there was no significant difference in the morphology of adenomas between the two groups (Table 4). Detachment of the Endocuff occurred in two cases; however, in both cases, the device was easily retrieved using forceps. There were no major complications, such as massive bleeding or perforation, in both groups.

Table 4.

The Mean Number of Adenomas Detected per Patient and Features of Detected Adenomas

DISCUSSION

Colonoscopy is a widely performed procedure used to prevent colorectal cancer. The ADR is considered the prime quality indicator of colonoscopy [7]. ADR of trainees is generally lower than that of experts [23,24] and has been reported to be 23%–36% [25-27]. Although a previous study reported no significant difference in ADR between EAC and CAC [19], differences between these procedures when performed by trainees remain unclear. In the present study, the cecal intubation rate and time were similar between the two groups. The Endocuff is bulkier than the transparent cap and has an attached flap, which did not prove to be difficult to insert as it was easily folded at the time of insertion. The ADR and MAP were significantly higher in the EAC group than in the CAC group in the present study. Our findings suggest that trainees were able to detect more adenomas because the Endocuff ’s flap caught the colon fold, indicating that fewer polyps were missed. Therefore, the Endocuff was more effective for adenoma detection, particularly in the sigmoid colon, which is an area that is often difficult to observe in detail due to flexion. Several studies showed that Endocuff improves the ADR of the sigmoid colon compared with CC [28,29], supporting our findings. Although there was no significant difference in the ADR of each trainee between the two groups, this result was thought to be influenced by the small number of patients. Several previous studies reported that compared to CC, colonoscopy using Endocuff improved MAP [30,31] and resulted in a higher detection rate of polyps <10 mm or of type Is morphology [28,29]. In the present study, MAP was higher in the EAC group than in the CAC group, but no differences were noted in polyp size or morphology probably because this was a comparison between EAC and CAC, and not between EAC and CC, and CAC was also useful for polyp detection. In the present study, even though trainees were experienced in performing colonoscopies, ADR and MAP were relatively higher in both the EAC and CAC groups compared to the results of previous studies [25-27]. However, we did not investigate ADR of CC, so it is unclear whether ADR improved compared to CC. Furthermore, because we did not investigate the efficacy of EAC and CAC performed by experts, differences between trainees and experts remain unclear. Cap detachment occurred in two cases in the EAC group, but it was easily retrieved using forceps. In both cases, cap detachment occurred at the time of withdrawal of the scope from the anus. We, therefore, suggest that scope withdrawal from the anus should be performed carefully to prevent detachment of the Endocuff. Although not a cap-related complication, delayed bleeding after polypectomy occurred in one case in the EAC group. We could not evaluate the minor mucosal lacerations due to the retrospective design of the study, but no major complications such as massive bleeding or perforation were noted.

The present study has some limitations. First, this was a single-center, retrospective study with a small number of subjects. Because of the retrospective design, we could not investigate the patient’s family history of colorectal cancer, which is known to be a risk factor of colorectal neoplasms. Furthermore, the body mass index and history of gynecologic surgery of each patient, which may affect the cecal intubation time and rate, were also unable to be investigated [32-34]. In addition, more males were included in EAC group, although this was not statistically significant. In previous reports, it has been shown that the ADR of males is higher than that of females [35,36], so the male to female ratio in this study may have affected the ADR results. Second, the ADR may not be accurate as the unresected polyps were not pathologically evaluated. However, because the PDR and the mean number of polyps detected per patient were higher in the EAC group, we believe the ADR exhibited a similar trend. Third, it was difficult to evaluate the bowel preparation quality accurately due to the study’s retrospective design. Therefore, we excluded patients with obviously inadequate bowel preparation as determined by reviewing the images. Fourth, each trainee performed colonoscopies for a different length of time, introducing potential selection bias.

In conclusion, to the best of our knowledge, this is the first study comparing the efficacy of EAC and CAC in trainees. The ADR and MAP of EAC were significantly higher than those of CAC, suggesting that EAC may be more useful than CAC when performed by trainees. A future, multicenter, randomized controlled trial is therefore required to further the results of this study.

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