SEARCH · Search PubMed

Results for “Polyps”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 253 records · Page 14Linked to original sources

PubMed1994

Frequency, location, and age and sex distribution of various types of gastric polyp.

Data on the frequency and location of the various types of gastric polyps are highly inconsistent. In a retrospective analysis of 5515 gastric polyps obtained from 4852 patients in the period between 1969 and 1989, including reexamination of 197 surgical, 1572 polypectomy, and 3746 biopsy specimens, the most frequent types found were Elster's glandular cysts (fundic gland polyps) (47.0%), followed by hyperplasiogenous polyp (28.3%), tubular adenoma (9.0%), adenocarcinoma (7.2%), inflammatory fibroid polyp (3.1%), carcinoid tumor (1.7%), Brunner's gland heterotopia (1.2%), and tubulopapillary adenoma (1.0%). Peutz-Jeghers polyps, juvenile polyps, and pancreatic heterotopia were found in younger patients (mean ages: 33.39 and 45 years, respectively), whereas the age of most patients (66%) with glandular cysts was between 40 and 69 years. Patients with any of the other types of gastric polyps were mostly (55-100%) over 60 years of age at the time of diagnosis. Glandular cysts, hyperplasiogenous polyps, inflammatory fibroid polyps, and carcinoid tumors were significantly more common in women, while all the other polyps were more or less equally distributed between the sexes. Glandular cysts and carcinoid tumors were relatively small (mean diameter 8 mm), and were mostly located in the corpus (100% and 83%, respectively). Medium-sized pancreatic heterotopias, Brunner's gland heterotopias, and inflammatory fibroid polyps (mean sizes 7-10 mm) were usually located in the antrum (100%, 81%, 80%, respectively), while the other polyps had an average size of between 10 and 16 mm and were distributed equally throughout the stomach.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenocarcinoma↗

PubMed2002

Pressure dye-spray: a simple and reliable method for differentiating adenomas from hyperplastic polyps in the colon.

BACKGROUND: Based on 10 years of experience with chromoendoscopy, our hypothesis was that colonic adenomas can be differentiated from hyperplastic polyps by use of a high-pressure spray-jet of dye (pressure dye-spray). To test the accuracy of pressure dye-spray, classification of colonic polyps as adenomas and hyperplastic polyps by pressure dye-spray and ordinary colonoscopic findings (shape, size, and color surface appearance) were compared. METHODS: Pressure dye-spray chromoendoscopy was performed by using 0.035% indigo carmine, a spray-type cannula, and a water pump. Polyps were first classified as adenomas or hyperplastic polyps by ordinary colonoscopic findings. One or more pressure dye-spray bursts were then focused on the polyp from a distance of 1 to 2 cm. Polyps were classified as adenomas only if oozing of blood was evident; otherwise, they were classified as hyperplastic polyps. A histologic diagnosis was obtained for all polyps, and the results of ordinary colonoscopic findings and pressure dye-spray were compared. RESULTS: This study examined 1468 polyps (1201 adenomas, 267 hyperplastic polyps; mean diameter 4 mm). The sensitivities for polyp differentiation with pressure dye-spray and ordinary colonoscopic findings were, respectively, 97.9% and 73.4% (p < 0.0001); specificities were, respectively, 96.6% and 92.1% (p = 0.077). CONCLUSIONS: Pressure dye-spray was found to be a reliable technique for differentiation between adenomas and hyperplastic polyps.

Adenoma↗

PubMed1998

The relationship between faecal bile acid profile with or without supplementation with calcium and antioxidants on recurrence and growth of colorectal polyps.

Faecal bile acids (FBA) have been implicated in colon carcinogenesis. The results of case-control studies of colorectal cancer and polyp patients are, however, conflicting. The aim of this study was to examine the influence of faecal bile acids on occurrence, growth and recurrence of colorectal polyps, and to see if a mixture of calcium and antioxidants might possibly act on cancer precursors through the effect on FBA. A total of 116 polyp-bearing patients were recruited from the outpatients department. Polyps < 10 mm in diameter were left in situ and measured by annual colonoscopy for 3 years. The patients received placebo or a mixture of antioxidants and calcium carbonate, 1.6 g calcium ion daily. Faecal samples were collected annually; the first, 1 month after start of intervention, freeze dried and subjected to bile acid profile analysis. Two age and sex matched control groups were recruited (n = 35), one from healthy volunteers (healthy controls) and one from the outpatients referred for colonoscopy, with no polyps (hospital controls). Twelve of 47 patients from the healthy volunteers had polyps (healthy polyp patients). One or more adenomas were found in 93 patients. The faeces of the hospital controls had significantly higher concentrations of total and secondary bile acids than did the healthy controls. There was no difference in FBA profile between the polyp group and the hospital controls, but significantly higher concentration of total and secondary faecal bile acids in the healthy polyp patients compared with the healthy control group (P < 0.05). No increased concentration of FBA were found in the polyp patients with multiple polyps (n = 21) or previous treatment for colorectal cancer (n = 7). No associations between FBA profile and growth or recurrence of colorectal polyps were found. The polyp patients receiving active medication had higher faecal concentrations of total and secondary bile acids in the beginning of the study than at the end, in spite of a good compliance. The present study does not support bile acids as being important markers of initiation or growth of small and medium sized colorectal adenomas. In the present study the calcium and antioxidants did not seem to affect the growth or recurrence of colorectal adenomas by increased TBA excretion in the faeces.

Antioxidants↗

PubMed1994

Helicobacter pylori infection and fasting serum gastrin levels in a series of endoscopically diagnosed gastric polyps.

The occurrence of H. pylori infection and the levels of fasting serum gastrin (SEGA) were examined in 97 patients with different morphological types of endoscopically diagnosed gastric polyps. According to the histology of the polyps the series was divided into three groups: inflammatory polyps (43 cases), polyps with foveolar hyperplasia (25 cases), and hyperplastic polyps including adenomas (29 cases). The prevalence of H. pylori infection was significantly lower in patients with hyperplastic polyps (45%) and foveolar hyperplasia (48%) than in the group with inflammatory polyps (81%). SEGA levels were higher in patients with hyperplastic polyps (mean +/- sd: 335 +/- 298 pmol/l) and foveolar hyperplasia (183 +/- 216) than in patients with inflammatory polyps (89 +/- 127). Signs of so-called "autoimmune" gastric, i.e. corpus atrophy and presence of parietal cell antibodies, were commonly found in patients with hyperplastic polyps and foveolar hyperplasia, but rarely in patients with inflammatory polyps. These results suggest that the polyps with hyperplastic changes (hyperplastic polyps and foveolar hyperplasia) are in some of the cases closely related to autoimmune gastritis. The presence of corpus atrophy, hypoacidity and various types of metaplasia, which characterizes autoimmune gastritis, could explain the low prevalence of H. pylori and the high SEGA levels found in these patients.

Adenoma↗

PubMed1995

Ileostomy polyps, adenomas, and adenocarcinomas.

Ileostomy polyps are uncommon and poorly described. The aim of this study was to undertake a retrospective clinicopathological review of ileostomy polyps. Seven patients with 60 polyps arising on ileostomies performed for ulcerative colitis were studied. The histopathological evaluation of archival ileostomy biopsy specimens, polypectomy or excision specimens, and clinical review of patient records was undertaken. Fifty of 60 polyps were inflammatory cap polyps and six further polyps were composed of granulation tissue only. They occurred anywhere on the stoma at any time after ileostomy construction and were strongly associated with overt stomal prolapse. Four neoplastic polyps were identified in two patients 27-36 years after ileostomy construction; all occurred at the mucocutaneous junction. One patient presented with a 2 cm polypoid invasive adenocarcinoma while in the second a 1.7 cm polypoid mucinous adenocarcinoma and a 0.7 cm ileal tubular adenoma with high grade dysplasia occurred at the site of excision of a cap polyp showing focal low grade adenomatous dysplasia six years previously. Neoplastic and non-neoplastic polyps could not be differentiated clinically. It was found that most ileostomy polyps are inflammatory cap polyps associated with stomal prolapse. Less common are polypoid adenomas or adenocarcinomas arising at the mucocutaneous anastomosis > 20 years after ileostomy construction. To prevent ileostomy carcinoma it is recommended that a biopsy of all polyps at the mucocutaneous anastomosis and of any non-prolapse associated polyps elsewhere on the stoma occurring > 15 years after ileostomy construction is done.

Adenocarcinoma↗

PubMed2001

Model of estimated rates of colorectal cancer from polyp growth by year of surveillance.

OBJECTIVE: Most studies show protective effects of non-steroidal anti-inflammatory drugs (NSAIDs) against polyps and colorectal cancers (CRCs) of up to 50%. Current models are unable to directly estimate changes in effects of chemoprevention on CRCs. The purpose is to develop a model to examine effects of changes in growth rates of polyps on surveillance intervals and risk of CRC. METHODS: The growth model simulates 500 people after polypectomy, estimating number and size of polyps annually over 10 years. Each polyp is assigned a random growth rate consistent with distributions of empirically observed growth assumed to follow a log linear model. Rates of CRC were calculated from largest polyps distributed to people. RESULTS: Simulated distributions of polyps and CRCs closely match empirical estimates which confirms the usefulness of the model. If polyp growth is 25% of normal, the number of cancers by year 10 after index colonoscopy decrease from 146 to only 57/100 000 for those in risk group 0 (no polyps at index colonoscopy) and from 840 to 124/100 000 for those of risk group 3 (4 or more polyps). CONCLUSIONS: This is the first model based on polyp growth rates. The CRC rates suggest that for those with no polyps on index colonoscopy, surveillance may be as for people of average risk (7-10 years), whereas those with one polyp or more need more surveillance (2-5 years). The use of the model is the indication that surveillance intervals could be increased by as much as 2-10 years if the growth rates of polyps are slowed.

Colonic Polyps↗

PubMed2002

Computerized detection of colonic polyps at CT colonography on the basis of volumetric features: pilot study.

PURPOSE: To develop a computer-aided diagnosis (CAD) scheme for automated detection of colonic polyps on the basis of volumetric features and to assess its accuracy on the basis of colonoscopy, the standard. MATERIALS AND METHODS: Computed tomographic (CT) colonography was performed in patients with use of standard bowel cleansing, air insufflation, and helical scanning in supine and prone positions. The colon was extracted from volumetric data sets generated from transverse CT sections. Volumetric features characterizing polyps were computed at each point in the extracted colon. Polyps were detected by means of hysteresis thresholding and fuzzy clustering followed by a rule-based test on the basis of feature values. Locations of the detected polyps were compared with those detected at conventional colonoscopy. RESULTS: Forty-one cases were analyzed: nine cases with polyps and 32 without polyps. Each case with polyps had one polyp of clinically important size (six were 5-9 mm; three, 10 mm). Thus, there were 82 volumetric data sets, 18 included polyps. Eighty-nine percent (16 of 18) of the polyps were detected. Each of the two false-negative findings was detected in the other position; thus, 100% of polyp cases were detected, with 2.5 false-positive findings per patient. The false-positive findings were similar to those due to common perceptual errors. Most of the false-positive findings were easily distinguishable from true polyps by experienced radiologists. CONCLUSION: The CAD scheme has the potential to depict polyps with high sensitivity and an acceptable false-positive rate.

Adult↗

PubMed2004

Nonadenomatous polyps at CT colonography: prevalence, size distribution, and detection rates.

PURPOSE: To prospectively investigate with computed tomographic (CT) colonography the prevalence and size distribution of nonadenomatous polyps in asymptomatic adults and to compare the detection rates of adenomatous and nonadenomatous polyps. MATERIALS AND METHODS: A total of 1233 asymptomatic adults (mean age, 57.8 years; 505 women, 728 men) underwent same-day CT colonography and optical colonoscopy procedures. CT colonoscopy studies were interpreted prospectively with a primary three-dimensional approach immediately before optical colonoscopy. Statistical analysis was performed with the chi(2) test. Size, prevalence, and by-polyp detection differences were compared between adenomatous and nonadenomatous polyps. RESULTS: Seven hundred fifty-six (57.7%) colorectal polyps identified at optical colonoscopy in 410 (33.3%) patients were nonadenomatous; of these lesions, 622 (82.3%) were diminutive (</=5 mm). Nonadenomatous polyps accounted for 622 (64.4%) of 966 diminutive lesions and 134 (39.9%) of 344 polyps 6 mm or larger (P <.001). The prevalence rate for nonadenomatous polyps was 8.8% (109 of 1233 patients) and 2.0% (25 of 1233 patients) at 6- and 10-mm thresholds, respectively. CT colonography by-polyp sensitivity for nonadenomatous lesions was 73.1% (98 of 134 patients) and 73.3% (22 of 30 patients) at 6- and 10-mm thresholds, respectively, compared with 85.7% (180 of 210 patients) and 92.2% (47 of 51 patients) for adenomas (P <.01). In 1065 patients that did not have a 6-mm or larger adenoma at optical colonoscopy, CT colonography depicted a nonadenomatous polyp that was 6 mm or larger in 63 (5.9%) patients and a nonadenomatous polyp that was 10 mm or larger in 15 (1.4%) patients. CONCLUSION: More than 80% of nonadenomatous polyps were diminutive, but they accounted for nearly 40% of polyps that were 6 mm or larger. Fortunately, CT colonography is significantly (P <.01) less sensitive in the detection of lesions that have no malignant potential when compared with similar-sized adenomas that have malignant potential.

Aged↗

PubMed1990

Atypical hyperplastic polyps at double-contrast barium enema examination.

At radiography, hyperplastic polyps classically appear as smooth, sessile elevations less than 5 mm in diameter. However, a retrospective review of double-contrast barium enema studies in 22 patients with 31 pathologically proved hyperplastic polyps revealed an average polyp size of 7.3 mm, with a range of 3-21 mm. Fifteen polyps (48%) were 2-5 mm, 12 (39%) were 6-10 mm, and four (13%) were greater than 10 mm in diameter. Twenty-nine polyps (94%) were sessile, and two polyps (6%) were pedunculated. Twenty-three polyps (74%) had a smooth contour, and eight polyps (26%) were lobulated. Twenty-six of the hyperplastic polyps (84%) were located in the rectosigmoid colon. If the radiologic criteria for an atypical hyperplastic polyp at double-contrast barium enema examination include size greater than 5 mm, lobulation, and/or pedunculation, 16 of the 31 hyperplastic polyps (52%) could be classified as atypical. Thus, radiologists should be aware that many hyperplastic polyps seen at double-contrast barium enema examination do not fit the classic description of a smooth, sessile elevation less than 5 mm in size but instead appear as larger, more lobulated lesions that are indistinguishable from adenomatous polyps.

Adult↗

PubMed1998

Colonic polyps in children: frequently multiple and recurrent.

A retrospective chart review on 77 children and adolescents (45 males and 32 females) with colorectal polyps seen over a 15-year period (1980-1994) was undertaken. Their presenting symptoms, demographic data, methods of diagnosis, pathologic diagnosis, and outcome were assessed. The age at presentation varied from 6 months to 19 years (mean age 77 months), 66.2% presenting under 6 years of age. The presenting symptoms were rectal bleeding in 71 patients, mass per rectum in 12, abdominal pain in nine, diarrhea in nine, vomiting in two, and one patient was asymptomatic. Air contrast barium enema was confirmatory in 41/54 patients (76%). Polyps were palpable in 16 patients during the rectal examination. A single polyp was present in 50 patients, whereas two to five polyps were present in 20 patients, and more than five in seven patients. Successful endoscopic removal was accomplished in 71/73 patients (97.3%). In 83.1% of patients polyps were located in the rectosigmoid area and in 32.5% polyps occurred proximal to the sigmoid colon. However, multiple polyps in the same location or at other locations were also present simultaneously. Recurrence was observed in five of 63 patients (7.9%) with juvenile polyps, in one patient with infantile polyposis, and in one with solitary adenomatous polyp. We conclude that a full colonoscopic evaluation should be performed in all patients with suspected polyps if feasible, for multiple polyps occurred in 35% of children without polyposis syndromes in this series. Parents of patients with more than three polyps and/or a family history of juvenile polyposis should be warned regarding the possibility of an increased risk of malignancy in future if polyps continue to recur.

Adolescent↗

PubMed1994

Prospective study of prevalence and endoscopic and histopathologic characteristics of duodenal polyps in patients submitted to upper endoscopy.

BACKGROUND: Retrospective studies of duodenal polyps have shown a prevalence of 0.3%-1.5% in patients referred to upper endoscopy, and histopathologic classifications have been inconsistent. METHODS: A prospective consecutive study was carried out in 584 patients referred to diagnostic upper endoscopy. Symptoms were registered on a questionnaire, endoscopic and histopathologic findings on standard forms. The same pathologist evaluated all biopsy specimens. RESULTS: Twenty-seven patients had polyps in the first and/or second part of the duodenum, for a prevalence 4.6%. Sixteen polyps were either inflammatory (nine polyps) or ectopic gastric mucosa (seven polyps). Both of these polyp types were practically always non-solitary, sessile, small, and located in the duodenal bulb. Seven polyps were covered by normal mucosa, three being endoscopically typical lipomas. Two polyps were adenomas (0.4% of all the patients and 7% of the polyps), and both were found in the descending part. One hyperplastic polyp of the gastric type and one case of fibrosis were found. CONCLUSIONS: 1) Duodenal polyps are found in 4.6% of patients referred to upper endoscopy and should therefore be looked for. 2) Multiple, small polyps in the duodenal bulb are always benign and need neither biopsy nor treatment (in patients with familial polyposis biopsy is recommended). 3) In the descending duodenum polyps are rare, but a substantial number of them are adenomas. Biopsy is therefore mandatory in this localization.

Adenoma↗

PubMedDate not supplied

[Gastric polyps and histological changes in surrounding mucosa].

PURPOSE: Gastric polyps are elevated epithelial lesions which pathogenesis and natural history are not well known. The purpose of this study was to determine the association between gastric polyps and histological changes of the surrounding mucosa. MATERIAL AND METHODS: Prospective, descriptive and transversal study. From 6603 patients examined through upper endoscopy at the National Hospital Edgardo Rebagliati Marins (Lima-Peru) from January 2002 to May 2003,115 gastric polyps were detected (1.74%) 68 of which were included in this study. Gastric polyps were examined through endoscopy and thereafter excised, taking biopsies of the surrounding mucosa. The histological examination established the gastric polyp type and the presence of inflammation, activity (infiltration with polymorphonuclears), atrophy, metaplasia, and Helicobacter pylori in the surrounding mucosa. RESULTS: Frequency of gastric polyps was as follows: hyperplastic: 51 (75%) adenomatous: 11 (16.2%) of fundic glands: 4 (5.9%) and inflammatory: 2 (2.9%). The mucosa surrounding hyperplastic polyps was characterized by the statistically significant presence of inflammation (100%, p=0.0001) and activity (84.3%, p=0.001) while the mucosa surrounding the adenomatous polyps showed statistically significant presence of inflammation (100%, p=0.0001) activity (81.8%, p=0.001), atrophy (72.7%, p=0.017) and metaplasia (72.7%, p=0.017). The severity of atrophy and metaplasia was significantly higher in the mucosa surrounding adenomatous polyps than in that surrounding hyperplastic polyps (p=0.019 and p=0.001). CONCLUSIONS: Hyperplastic polyps are associated with the presence of inflammation and activity in the surrounding mucosa, whereas adenomatous polyps are associated with the presence of inflammation, activity, atrophy, and metaplasia in the surrounding mucosa. Atrophy and metaplasia were more severe in the mucosa surrounding adenomatous polyps.

Aged↗

PubMedDate not supplied

Expression, localization, and significance of vascular permeability/vascular endothelial growth factor in nasal polyps.

BACKGROUND: The exact etiologic mechanisms leading to the formation of nasal polyps have remained largely obscure. A key phenomenon of this specific type of chronic inflammatory disease in nasal respiratory mucosa is remarkable edema. Vascular permeability/vascular endothelial growth factor (VPF/VEGF) plays an important role in inducing angiogenesis and modulating capillary permeability. OBJECTIVE: To study the expression and localization of VPF/ VEGF as a putative key factor in nasal polyp development. METHODS: Specimens of nasal polyps (n = 12) were harvested during endonasal sinus surgery in patients with polypous chronic rhinosinusitis. Specimens of healthy nasal respiratory mucosa (n = 12) served as controls and were obtained from inferior turbinates of patients undergoing surgery for nasal obstruction without signs and symptoms of inflammatory disease. Frozen sections were immunohistochemically stained for VPF/VEGF and quantitatively analyzed, using computer-based image analysis. RESULTS: The expression of VPF/VEGF in specimens of nasal polyps was significantly stronger than in specimens of healthy nasal mucosa of controls. VPF/VEGF in polypous tissue was mainly localized in vascular endothelial cells, in basal membranes and perivascular spaces, and in epithelial cells. CONCLUSION: The markedly increased expression in nasal polyps as opposed to healthy nasal mucosa suggests that VPF/VEGF may play a significant role in both the formation of nasal polyps and in the induction of heavy tissue edema. This finding is discussed with respect to the differential expression of cyclooxygenase (COX) isoenzymes-1 and -2 (COX-1 and COX-2) in nasal polyps was significantly stronger than in specimens of healthy nasal mucosa of controls. VPF/VEGF in polypous tissue was mainly localized in vascular endothelial cells, in basal membranes and perivascular spaces, and in epithelial cells. Conclusion: The markedly increased expression in nasal polyps as opposed to healthy nasal mucosa suggests that VPF/VEGF may play a significant role in both the formation of nasal polyps and in the induction of heavy tissue edema. This finding is discussed with respect to the differential expression of cyclooxygenase (COX) isoenzymes-1 and -2 (COX-1 and COX-2) in nasal polyps.

Adult↗

PubMed2005

The rate of adenocarcinoma in endoscopically removed colorectal polyps.

The purpose of this study was to determine the rate of cancer in a modern series of colorectal polyps. All pathology reports from colon and rectal polyps from 1999 to 2002 were reviewed. Reports of bowel resections, cancer-free polyps, and polyp-free mucosal biopsies were excluded. Polyps were grouped by size, and the rate of adenocarcinoma was determined. x2 was used for analysis. A total of 4,443 polyps were found, of which 3,225 were adenomatous [2,883 (89.4%) tubular adenomas, 399 (9.3%) tubulo-villous adenomas, 32 (1.0%) villous adenomas, and 11 (0.3%) carcinomas]. The rate of adenocarcinoma by size was 0.07 per cent for polyps <1 cm, 2.41 per cent for polyps 1-2 cm, and 19.35 per cent for polyps >2 cm, representing significantly fewer cancers for each category of polyp size than the accepted standard. The rate of carcinoma in colon polyps is much lower than previously thought and currently stated in many texts. These data do not alter the recommendations for polyp removal, however, failure to retrieve a specimen in a polyp <1 cm in size is unlikely to have an adverse outcome because the chances of malignancy are very low.

Adenocarcinoma↗

PubMed1997

Genetic alterations and epithelial dysplasia in juvenile polyposis syndrome and sporadic juvenile polyps.

Juvenile polyps are regarded as hamartomatous polyps and occur in sporadic and familial syndromic settings. There is increased risk of gastrointestinal neoplasia in patients with juvenile polyposis syndrome, but the molecular mechanisms are not known. We therefore studied 78 colorectal juvenile polyposis from 12 patients with juvenile polyps syndrome and 34 sporadic juvenile polyps for epithelial dysplasia and genetic changes associated with colorectal neoplasia. Dysplasia occurred in 31% of syndromic juvenile polyps but not in sporadic juvenile polyps (P < 0.0001). Topographic control of proliferation and expression of the cyclin-dependent kinase inhibitor p21(WAFI/CIP1) seen in native colorectal epithelium was lost in 79% of dysplastic juvenile polyps and in 8% of nondysplastic juvenile polyps (P < 0.000001). Somatic mutations in the adenomatous polyposis coli (APC) gene were demonstrated in 50% of dysplastic juvenile polyps (3 of 6) but not in any of 16 juvenile polyps without dysplasia (P = 0.01). Both sporadic and syndromic juvenile polyps had K-ras mutations (14%) and there was no relationship to dysplasia. p53 gene product overexpression identified by immunohistochemical staining occurred rarely in dysplastic juvenile polyps (2 of 24, 8%). Our results indicate that the multiple genetic alterations involved in usual colorectal neoplasia also play a role in neoplastic transformation of juvenile polyps, predominantly in juvenile polyposis syndrome.

Adenomatous Polyposis Coli↗

PubMed2026

Comparative Efficacy of Different AI Systems for Polyp Detection by Size During Colonoscopy: Systematic Review and Network Meta-Analysis.

BACKGROUND: Colorectal cancer remains a leading cause of death despite being largely preventable through polypectomy. AI systems designed to enhance polyp detection during colonoscopy have shown promise, but the extent to which they improve detection of different-sized polyps remains unclear. OBJECTIVE: This study compared the size-stratified efficacy of AI-assisted colonoscopy vs standard colonoscopy using the Hartung-Knapp-Sidik-Jonkman (HKSJ) method, and generated exploratory rankings while acknowledging all cross-platform comparisons are indirect. METHODS: This systematic review and network meta-analysis (NMA) searched PubMed, Embase, Cochrane CENTRAL, and Web of Science from inception to July 25, 2026, supplemented by citation searching. We included randomized controlled trials (RCTs) comparing AI-assisted vs standard colonoscopy in adults (≥18 years of age), reporting mean polyp detection counts stratified by size (≤5 mm, 6-9 mm, and ≥10 mm). Two reviewers screened studies, extracted data, and assessed risk of bias using the Cochrane Risk of Bias 2.0. We conducted frequentist NMA using the HKSJ method with restricted maximum likelihood estimation, calculated 95% prediction intervals (PIs), and assessed heterogeneity using I2 and τ2. Certainty of evidence was rated using the GRADE (Grading of Recommendations Assessment, Development, and Evaluation) framework. RESULTS: A total of 13 RCTs (4156 participants) compared 8 AI systems to standard colonoscopy, forming a network without direct AI comparisons. For diminutive polyps (≤5 mm), AI showed a modest advantage (standardized mean difference [SMD] 0.21, 95% CI 0.07 to 0.35, 95% PI -1.12 to 1.54), but substantial heterogeneity (I2=86.6%) and wide PI crossing the null indicated high uncertainty. EndoScreener showed the most consistent evidence (SMD 0.36, 95% CI 0.18-0.54). For small and large polyps, effects were minimal (SMD 0.02, 95% CI -0.02 to 0.06, 95% PI -0.03 to 0.07; SMD 0.01, 95% CI 0.00-0.02, 95% PI -0.01 to 0.03). GRADE certainty was very low for diminutive polyps and low for small and large polyps. Sensitivity analysis excluding Tianjin YuJin did not materially change findings. CONCLUSIONS: AI may modestly enhance diminutive polyp detection, but effects on small and large polyps are minimal, with no platform superiority. Given very low to low certainty, findings are hypothesis-generating. This exploratory NMA provides size-stratified comparisons that can inform future head-to-head trial design. Unlike prior reviews aggregating all polyp sizes, we show the overall AI benefit is driven by diminutive polyp detection, providing a framework for targeted deployment-prioritizing AI for diminutive polyp screening, with limited value for larger lesions. Head-to-head trials are urgently needed. TRIAL REGISTRATION: PROSPERO International Prospective Register of Systematic Reviews CRD420251266932; https://www.crd.york.ac.uk/PROSPERO/view/CRD420251266932.

Colonoscopy↗

PubMed2004

Low prevalence of loss of heterozygosity and SMAD4 mutations in sporadic and familial juvenile polyposis syndrome-associated juvenile polyps.

BACKGROUND: Juvenile polyps (JP) may develop sporadically or may be associated with the familial juvenile polyposis syndrome (FJPS). In FJPS, the epithelium is susceptible to dysplasia and, ultimately adenocarcinoma. However, the mechanisms involved in this transformation are unknown. Since the epithelium in colorectal carcinogenesis undergoes a stepwise genetic progression, the purpose of this study was to determine if loss of heterozygosity (LOH) abnormalities can aid in the differentiation between sporadic and FJPS-associated polyps. DESIGN: Ninety-one routinely-processed JP from three groups of patients were evaluated for this study. Group 1 included 39 polyps from 39 patients with a single JP and no personal or family history of FJPS; group 2 consisted of 24 polyps from 15 patients with 2-5 JP and no history of FJPS; and group 3 included 29 polyps from 22 patients with > or =5 polyps either with (7) or without (15) a family history of FJPS. Epithelium from typical, atypical, and overtly dysplastic polyps, when present (2 cases in group 3 only), were evaluated separately by microdissection and PCR analysis for LOH of APC, p53, 3p, 9p, and mutations in exon 9 of the SMAD4 gene. RESULTS: SMAD4 mutations were observed in 3 polyps from 2 patients in group 3 (10% of informative cases; p < 0.05 vs group 1), but not in any of the polyps from the other two groups. Overall, LOH of APC, p53, 3p, and 9p were detected in 1%, 15%, 10%, and 4% of JPs, but no differences were observed between the three clinical groups. Two polyps, both in group 3, with definite dysplasia did not show any genetic alterations. The morphologic appearance of the polyps was not a reliable feature in helping to differentiate sporadic from FJPS-associated polyps. CONCLUSIONS: LOH of APC, p53, 3p, and 9p may not be involved in the carcinogenic pathway of FJPS-associated polyps. SMAD4 gene mutations show a low sensitivity but a high specificity for FJPS.

Adenomatous Polyposis Coli↗

PubMed2000

Somatic mutations of LKB1 and beta-catenin genes in gastrointestinal polyps from patients with Peutz-Jeghers syndrome.

Peutz-Jeghers syndrome (PJS) is characterized by multiple gastrointestinal hamartomatous polyps, mucocutaneous melanin deposition, and increased risk of cancer, mainly in the gastrointestinal tract. We examined mutations of the LKB1, beta-catenin, APC, K-ras, and p53 genes in 27 gastrointestinal hamartomatous polyps from 10 patients in nine PJS families. Of these hamartomatous polyps, one intestinal polyp had an adenomatous lesion, and one gastric polyp contained adenomatous and carcinomatous lesions. Germ-line mutations of the LKB1 gene were detected in six PJS families. Somatic mutations of the LKB1 gene were found in 5 polyps, whereas loss of heterozygosity (LOH) at the LKB1 locus at 19p was seen in 14 other polyps. In adenomatous lesions microdissected from hamartomatous polyps, both beta-catenin mutation and 19p LOH were detected. Furthermore, a carcinomatous lesion in a gastric hamartomatous polyp was found to contain a mutation of the p53 gene and LOH at the p53 locus in addition to LOH at the LKB1 locus and a beta-catenin mutation. K-ras mutations were detected in a few polyps, whereas no APC mutation or 5q LOH was detected in hamartomatous polyps. These results suggest that gastrointestinal hamartomatous polyps in PJS patients develop through inactivation of the LKB1 gene by germ-line mutation plus somatic mutation or LOH of the unaffected LKB1 allele, and that additional mutations of the beta-catenin gene and p53 gene convert hamartomatous polyps into adenomatous and carcinomatous lesions.

AMP-Activated Protein Kinase Kinases↗