Colon Capsule Endoscopy for the Detection of Colorectal Polyps: An Evidence-Based Analysis

Abstract

Background: Colorectal cancer, a leading cause of mortality and morbidity in Ontario, can be prevented through early diagnosis and removal of precancerous polyps. Colon capsule endoscopy is a relatively new, minimally invasive test for detecting colorectal polyps.

Objective: The objectives of this analysis were to evaluate the diagnostic accuracy and safety of colon capsule endoscopy for the detection of colorectal polyps among adult patients with signs or symptoms of colorectal cancer or with increased risk of colorectal cancer, and to compare colon capsule endoscopy with alternative procedures.

Review methods: A literature search was performed using Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid EMBASE, the Wiley Cochrane Library, and the Centre for Reviews and Dissemination database, for studies published between 2006 and 2014. Data on diagnostic accuracy and safety were abstracted from included studies. Quality of evidence was assessed using Grading of Recommendations Assessment, Development, and Evaluation (GRADE).

Results: The search yielded 2,189 citations. Five studies, all of which evaluated PillCam COLON 2 (PCC2), met the inclusion criteria. The per-patient sensitivity and specificity for detecting colorectal polyps were meta-analyzed. Colon capsule endoscopy, using PCC2, had a pooled sensitivity and specificity of 87% (95% confidence interval [CI] 77%-93%) and 76% (95% CI 60%-87%), respectively, for the detection of a colorectal polyp at least 6 mm in size (GRADE: very low). PCC2 had a pooled sensitivity and specificity of 89% (95% CI 77%-95%) and 91% (95% CI 86%-95%), respectively, for the detection of a colorectal polyp at least 10 mm in size (GRADE: low). One study directly compared PCC2 with computed tomographic (CT) colonography and found no statistically significant difference in accuracy (GRADE: low). Few adverse events were reported with PCC2; 3.9% of patients (95% CI 2.4%-6.5%) experienced adverse effects related to bowel preparation. Capsule retention was the most serious adverse event and occurred in 0.8% of patients (95% CI 0.2%-2.4%) (GRADE: very low).

Conclusions: In adult patients with signs, symptoms, or increased risk of colorectal cancer, there is low-quality evidence that colon capsule endoscopy using the PCC2 device has good sensitivity and specificity for detecting colorectal polyps. Low-quality evidence does not show a difference in accuracy between colon capsule endoscopy and CT colonography. There is very low-quality evidence that PCC2 has a good safety profile with few adverse events; capsule retention is the most serious complication.

Figure 1:. Citation Flow Chart

Figure 2:. Forest Plots of Accuracy of PillCam COLON 2 in the Detection of Colorectal Polyps of Varying Sizes

Figure 3:. SROC Curves of PillCam COLON 2 in the Detection of Colorectal Polyps of Various Sizes