Surveillance after positive colonoscopy based on adenoma characteristics

BackgroundPatients with adenomatous polyps are at increased risk for developing colorectal cancer based on the characteristics and number of polyps, but less is known about the individual and combined contribution of these factors. This study aimed to better characterize the risk of advanced adenoma and cancer in patients with positive baseline colonoscopy.MethodsPatients who had polyps at baseline colonoscopy were included in this retrospective cohort study (N = 1165) and were categorized into 6 groups: (1) 1–2 non-advanced adenomas (NAA’s), (2) ≥3 NAA’s, (3) advanced tubular adenoma, (4) small tubulovillous adenoma (TVA), (5) large TVA and (6) multiple advanced adenomas (MAA’s). Findings at surveillance colonoscopy were documented in each group.ResultsThe combined incidence of advanced adenoma, ≥3 NAA’s, and colorectal cancer at surveillance colonoscopy was significantly higher in the baseline large TVA (29.2%) than small TVA groups (13.5%, P < 0.001), as well as in the MAA’s group (44.1%) compared with large TVA group (P = 0.02). The incidence of colorectal cancer, however, was not significantly different between the groups.ConclusionsThe size of the polyp and the number of advanced lesions are more important than its histology for predicting the risk of high-risk metachronous lesions at follow-up.     

Colonoscopy in patients with psoriasis before the initiation of treatment with biological agents

Psoriasis may lead to subsequent colorectal cancer, since chronic systemic inflammation is the common etiologic factor in both psoriasis and colorectal cancer. It is a matter of dispute whether biological agents used in the treatment of psoriasis cause predisposition to colorectal cancer as a result of their immunosuppressive effect. Medical records of psoriasis patients who underwent colonoscopy before biological agents were reviewed. Colonoscopy was performed in all patients who were aged 50 years and older and in patients younger than 50, if they had positive fecal occult blood test results. The study included 95 patients between the age of 34 to 84. Colonoscopy results revealed tubular adenoma in 16 (16.8%) patients, hyperplastic polyps in 7 (7.4%) patients, villous adenoma in 1 (1.1%) patient, and tubulovillous adenoma in 1 (1.1%) patient. Two patients were diagnosed with colon cancer detected by a former colonoscopy, which was recommended by their dermatologist before the biological agent treatment plan. These results revealed that adenomatous polyps which can evolve to colon adenocarcinoma were the most frequent polyp type in patients with psoriasis. We suggest that routine colonoscopy should be performed before the initiation of biological therapy in psoriasis patients who are aged 50 years old and over.     

Full-driving soft robotic colonoscope in compliant colon tissue

Robotic colonoscopy is an efficient examination method for finding malignant tumour in its early stage. This research developed a novel robotic endoscope with 13?mm diameter, 105?mm length and 22.3?g weight. A contact biomechanical model is proposed to increase the locomotion safety and efficiency in the soft tissue. The model shows that the friction difference between the robot and the tissue is a key factor to locomotion capability. A soft, full bellow with excellent compatibility was designed to package the robot body. The bellow increased the static friction and decreased the kinetic friction given the change in the contact state. The bellow is divided into three segments. Each segment is composed of a linear locomotor with micromotor, turbine-worm and wire wrapping–sliding mechanism. The robot is tested in in vivo pig colon, which revealed an excellent locomotion capability and safety in soft tissues.     

CAD techniques, challenges, and controversies in computed tomographic colonography

Computer-aided diagnosis (CAD) for computed tomographic colonography (CTC) automatically detects the locations of suspicious polyps and masses on CTC and provides radiologists with a second opinion. CAD has the potential to increase radiologists' diagnostic performance in the detection of polyps and masses and to decrease variability of the diagnostic accuracy among readers without significantly increasing the reading time. Technical developments have advanced CAD substantially during the past several years, and a fundamental scheme for the detection of polyps has been established. The most recent CAD systems based on this scheme produce a clinically acceptable high sensitivity and a low false-positive rate. However, CAD for CTC is still under active development, and the technology needs to be improved further. This report describes the expected benefits, the current fundamental scheme, the key techniques used for detection of polyps and masses on CTC, the current detection performance, as well as the pitfalls, challenges, controversies, and the future of CAD.