Colon capsule endoscopy (CCE) is a minimally invasive method for colon diagnostic imaging. It enables a minimally invasive and painless colonic examination without the need for air inflation or anesthesia. The role of CCE is rapidly changing, for instance, for colorectal screening (colorectal cancer) in patients with average risk, in patients who have had an incomplete colonoscopy, in patients who have refused a conventional colonoscopy, and in patients who have medical conditions that would make them contraindicated for a conventional colonoscopy.
What is a Colon Capsule Endoscope?
Batteries, LEDs, an antenna, and an imaging device are all components of a capsule endoscope. The imaging equipment transmits data to a recorder that the patient wears on their belt. The information is then downloaded as a video onto a computer for viewing and reporting. The smaller lumen and uniform cylindrical shape of the small bowel make it possible for a capsule endoscope to advance distally without considerable side-to-side movement or tumbling, but the higher colonic volume and haustral folds pose difficulties.
To offer simultaneous antegrade and retrograde views, this was addressed by mounting cameras at both ends of the capsule, however, trials with the initial model were underwhelming. However, the second iteration of the colon capsule endoscope is programmed to acquire images for 10–12 hours at a rate that varies according to the speed of transit: four images per second are obtained when the capsule is almost stationary up to a maximum of 35 per second when propelled rapidly by peristalsis. It also has an increased field of view (from 156o to 172o, providing a near 360o view). As per Extrapolate, the colon capsule endoscopy market is projected to grow USD 939.5 Mn in 2028 from USD 465.5 Mn in 2021, at a CAGR of 8.7%.
What is the CCE procedure?
For CCE to be successful, adequate bowel preparation is essential. In contrast to a traditional colonoscopy, extra cleaning techniques like washing and suctioning are not possible during the operation. The detection of colonic polyps may be hampered by even minute amounts of feces. To encourage capsule propulsion and excretion, colon preparation is also crucial. The preparation solution expands the colonic wall and fills the lumen with clear fluid, allowing for close inspection of the colonic mucosa and making capsule propulsion easier.
It is advised that subjects start a low-residue diet two days before CCE and switch to a clear liquid diet the day of CCE for successful CCE. A unique colon preparation regimen was used to maintain a clean colon and a clear capsule picture because the usual colonoscopy regimen (polyethylene glycol solution only) showed an insufficient ingestion rate. In earlier research, a PEG solution and boosters including sodium phosphate produced a successful bowel preparation.
Although a recent study has shown the equal efficacy of a non-split regimen, it is typically preferred to administer PEG on the evening before the exam and the morning of the exam. Boosters are necessary for the exam's completion and capsule excretion. A sodium phosphate booster works well to speed up transit. Other boosters including ascorbic acid and magnesium citrate were looked into because of concerns about sodium phosphate toxicity, such as acute kidney injury and electrolyte imbalance, however, they had low capsule excretion and completion rates.
Presently, a tiny amount of sodium phosphate is utilized as a booster, 40 mL with 1 L of water to be consumed once the capsule has entered the small intestine and 20 mL with 500 mL of water three hours later. Other medications, such as prokinetics for delayed stomach emptying and a suppository for delayed capsule expulsion, may also be given.
Future Scope of CCE
As a first-line diagnostic test for CRC screening, CCE has limitations because tissue samples cannot be obtained, and patients with substantial CCE findings still need to be referred for a traditional colonoscopy. CCE, however, might be useful as a filter test in the future. Although the fecal occult blood test is an effective screening method, its false-positive rate is quite high. The high percentage of people with positive occult blood test findings who do not have advanced adenoma or neoplasia on colonoscopy, places a financial burden on the patient and raises the possibility of colonoscopy-related problems. In a recent experiment, CCE was carried out following a fecal occult blood test to identify people who need a traditional colonoscopy.
CCE has been shown to reduce the need for needless conventional colonoscopies by 71% and to be successful in detecting polyps and cancers in people who have a positive fecal occult blood test. Several major prospective trials involving hundreds of individuals are currently being conducted in Europe to determine the relevance of CCE in CRC screening. By assessing the effectiveness of CCE in detecting CRC and advanced adenoma in fecal occult blood-positive individuals or the general population, these studies will offer insight into whether CCE is indeed helpful in CRC screening.
There is a lack of information on the usage of CCE in IBD patients. Because a biopsy and a histological diagnosis are required for the diagnosis of IBD, the function of CCE as a main diagnostic tool for IBD is constrained. To track the progression of the disease, CCE may have a role in the field of IBD by looking at mucosal repair. For a better clinical outcome and lower hospitalization and surgical resection rates, mucosal healing is a key objective of medical treatment for IBD. The utility of CCE in the monitoring of mucosal inflammation has been investigated in a number of research. An earlier study found that first-generation CCE had sensitivity and specificity of 89% and 75%, respectively, for identifying active ulcerative colitis.
CCE seems to be a viable innovative colonic assessment technique. It is a painless, non-invasive method that examines the intestinal mucosa directly. When a colonoscopy is not completed or when a patient is unwilling or unable to have one, CCE might offer extra information. The use of CCE may improve patient compliance because it is well tolerated by patients and can be done even in an outpatient setting. The future of CCE in the domain of CRC screening for the surveillance of polyps and adenomatous lesions as well as for the evaluation of IBD seems optimistic given the fast-evolving technologies.