Small Tubular Adenomas Research Articles

Colonoscopy quality measures and adherence to follow-up guidelines among endoscopists participating in a U.S. endoscopy registry

Colonoscopy screening can substantially reduce colorectal cancer incidence and mortality. Colonoscopies may achieve maximum benefit when they are performed with high quality and accompanied by follow-up recommendations that adhere to clinical guidelines. This study aimed to determine to what extent endoscopists met targets for colonoscopy quality from 2016 through 2019 (the most recent years prior to the COVID-19 pandemic). We examined measures of colonoscopy quality and recommended follow-up intervals in the GI Quality Improvement Consortium, a large nationwide endoscopy registry. The analysis included over 2.5 million outpatient screening colonoscopies in average risk adults aged 50-75 years. At least 90% of endoscopists met performance targets for adequate bowel preparation, cecal intubation rate, and adenoma detection rate. However, nonadherence to guidelines for follow-up intervals was common. For patients with no colonoscopy findings, 12.0% received a follow-up interval recommendation of ≤5 years instead of the guideline-recommended 10 years. For patients with 1-2 small tubular adenomas, 13.5% received a follow-up interval recommendation of ≤3 years instead of the guideline-recommended 5-10 years. For patients with small sessile serrated polyps, 30.7% received a follow-up interval recommendation of ≤3 years instead of the guideline-recommended 5 years. Some patients with higher risk findings received a follow-up interval recommendation of ≥5 years instead of the guideline-recommended 3 years, including 18.2% of patients with advanced serrated lesions. Additional attention may be needed to achieve more consistent adherence to guidelines for colonoscopy follow-up recommendations.

Randomized Trial of Patient Outreach Approaches to De-implement Outdated Colonoscopy Surveillance Intervals

Guidelines now recommend patients with low-risk adenomas receive colonoscopy surveillance in 7-10 years and those with the previously recommended 5-year interval be re-evaluated. We tested 3 outreach approaches for transitioning patients to the 10-year interval recommendation. This was a 3-arm pragmatic randomized trial comparing telephone, secure messaging, and mailed letter outreach. The setting was Kaiser Permanente Northern California, a large integrated healthcare system. Participants were patients 54-70 years of age with 1-2 small (<10 mm) tubular adenomas at baseline colonoscopy, due for 5-year surveillance in 2022, without high-risk conditions, and with access to all 3 outreach modalities. Patients were randomly assigned to the outreach arm (telephone [n= 200], secure message [n= 203], and mailed letter [n= 201]) stratified by age, sex, and race/ethnicity. Outreach in each arm was performed by trained medical assistants (unblinded) communicating in English with 1 reminder attempt at 2-4 weeks. Participants could change their assigned interval to 10 years or continue their planned 5-year interval. Sixty-day response rates were higher for telephone (64.5%) and secure messaging outreach (51.7%) vs mailed letter (31.3%). Also, more patients adopted the 10-year surveillance interval in the telephone (37.0%) and secure messaging arms (32.0%) compared with mailed letter (18.9%) and rate differences were significant for telephone (18.1%; 97.5% confidence interval: 8.3%-27.9%) and secure message outreach (13.1%; 97.5% confidence interval: 3.5%-22.7%) vs mailed letter outreach. Telephone and secure messaging were more effective than mailed letter outreach for de-implementing outdated colonoscopy surveillance recommendations among individuals with a history of low-risk adenomas in an integrated healthcare setting. (ClinicalTrials.gov, Number: NCT05389397).

The frequency of dysplastic branching crypts in colorectal polypoid tubular adenomas.

Dysplastic crypt branching (DCB) was recently found in ulcerative colitis-associated dysplasia. The aim was to assess the frequency and the branching phenotype of DCB in polypoid colorectal tubular adenomas (TA). A total of 3956 DCB were found in the 139 TA: 98% were in asymmetric branching (DCAB) and the remaining 2% in symmetric branching (DCSB). A linear correlation was found between DCB frequency and the increasing digital size in TA (p < .05). Using a digital ruler, adenomas were divided into small TA (<5 mm) and larger TA (≥5 mm). The difference between the frequency of DCB in small TA (n=75) vs. larger TA (n=64), was significant (p < .05). DCB frequency was not influenced by age, gender or TA localization. In the normal colorectal mucosa (≈2 m2 ), only occasional CSB is found and no CAB. And yet, multiple DCB (mean 16.7 DCB), mostly DCAB, was found in small TA, occupying <5 mm of the mucosal area. In larger TA, as many as 42.1 DCB (mean), mostly DCAB, occurred in merely 7.8 mm (mean) of the colon mucosa. Thus it is suggestedthat DCB is a standard histologic element of TA. The natural expansion of the adenomatous tissue in larger TA appears to be follow on from newly produced, mostly DCAB, by DCSB and by the accumulation of their dysplastic offspring's progenies. The findings strongly suggest that DCB is a central microstructure in the histological events unfolding in polypoid colorectal TA.

Disclosure and Reflection After an Adverse Event: Tips for Training and Practice

A 73-year-old woman with hypertension and hypothyroidism undergoes a surveillance colonoscopy for a history of nonadvanced adenomas. Her last colonoscopy was 5 years ago where 5 small tubular adenomas were removed with cold snare. A third-year gastroenterology (GI) fellow and attending meet and consent the patient for colonoscopy. Diverticula are noted throughout the left colon with associated restricted colonic mobility and a narrow luminal caliber, making insertion moderately difficult. Two small polyps are removed with cold snare from the ascending colon.

Diagnostic yield of repeat screening colonoscopy ten years after an adenoma-negative index screening endoscopy.

In Germany, colonoscopy was introduced as a screening instrument about 20 years ago. Ten years after an adenoma-negative index endoscopy, a second screening colonoscopy can be performed in younger persons, but this approach is based on limited evidence. We therefore prospectively analyzed the diagnostic yield of second screening colonoscopies in clinical routine.Ten years following adenoma-negative screening endoscopy a second screening colonoscopy was performed in 401 persons (210 women and 191 men); mean age was 70 years. A total of 244 benign neoplastic lesions were removed in 135 persons (34%). Eight persons had three or more small tubular adenomas removed; 19 persons had at least one tubular adenoma measuring ≥ 10 mm; 14 persons had adenomas with villous characteristics; 19 persons had serrated adenomas; one person had an adenoma with high grade dysplasia. Thus 61 persons (33 men and 28 women) were classified as bearing a significant risk for the development of colorectal cancer (15%). An additional patient had a low-risk malignant polyp removed endoscopically.We conclude that a significant number of small and advanced adenomas can be identified in a second screening colonoscopy ten years after an adenoma-negative index screening endoscopy, but malignant lesions are rare. Whether or not removal of the benign lesions in a second screening colonoscopy will reduce incidence and mortality of colorectal carcinoma remains to be seen in this elderly group.

Risk of total metachronous advanced neoplasia in patients with both small tubular adenomas and serrated polyps

The impact of concomitant small serrated polyps (SPs) on the risk of subsequent neoplasia when small tubular adenomas (TAs) are found is uncertain. Patients who on index colonoscopy had≤2 TAs of<10mm in size in isolation were compared with those with concomitant≤2 small-sized SPs. SP was inclusive of polyps described by pathology as sessile serrated lesions (SSLs) or proximal hyperplastic polyps (HPs)<10mm in size. The primary endpoint was the rate of total metachronous advanced neoplasia (T-MAN) compared among the TAs in the isolation group and the groups inclusive of SPs (SSLs or proximal HPs). For patients with TAs and small SPs found concomitantly, the rate of T-MAN was 9.6% (24/251), which was significantly higher than the rate of T-MAN in patients with isolated small TAs (5.2% [59/1138], P= .011). Within the concomitant SP cohort, the rate of T-MAN in the proximal HP subgroup remained significantly increased (9% [19/212]) compared with the isolated small TA group (P= .037). When small TAs are found concomitantly with small SPs, there is an increase in the rate of T-MAN in comparison with isolated TAs. This increase in T-MAN also occurs when small TAs are found in conjunction with small proximal HPs. The presence of concomitant small SPs should be considered in determining surveillance intervals when small TAs are identified in colonoscopy screening programs.

A Rare Hidden Mole, an Incidental Finding in Colonoscopy

Question: An 82-year-old man with hypertension, auricular fibrillation, with a pacemaker and mitral/aortic biological protheses was referred to our hospital for total colonoscopy owing to a positive fecal occult blood test. Two small tubular adenomas were found. In addition, a dark 3-mm-diameter macule in the anal canal closely below the pectinate line in the right anal wall was detected (Figure A). An endoscopic biopsy was performed under local anesthesia with mepivacaine and epinephrine. Histopathological images are shown in Figures B to D.

S234 Small Low-Risk Tubular Adenomas 5-9 mm Have an Increased Risk for Post Colonoscopy Colorectal Cancer: Data From the New Hampshire Colonoscopy Registry

S234 Small Low-Risk Tubular Adenomas 5-9 mm Have an Increased Risk for Post Colonoscopy Colorectal Cancer: Data From the New Hampshire Colonoscopy Registry

S3127 Colonic Polyp Surveillance Guidelines Are Appropriate for Younger Patients Despite Having Higher Grade Polyps on Surveillance Colonoscopy Compared With Older Patients

INTRODUCTION: Over the past few decades, the incidence of colorectal cancer (CRC) in the United States has been decreasing for older patients (OP, ≥50 years old), but increasing for younger patients (YP, < 50 years old). Current colonic polyp surveillance guidelines are primarily based on data from OP and may not be appropriate to use in YP given the reported increase in rates of CRC in YP. Our aim was to investigate whether existing colonic polyp surveillance guidelines created for OP are appropriate for use in YP. METHODS: We performed a retrospective cohort study of patients from two academic medical centers. We generated Risk Stratification Groups (RSG) based on surveillance colonoscopy intervals recommended by the USMSTF for CRC (Table 1). To determine if current colonic polyp surveillance guidelines were appropriate, we measured whether a patient's RSG worsened from index to surveillance colonoscopy, signifying that higher grade polyps were found on the subsequent surveillance colonoscopy compared to the index colonoscopy. Changes in RSG between OP and YP was determined using a McNeamer Test. A multivariate analysis was used to determine independent risk factors for RSG worsening. RESULTS: 1892 patients were included in the study, comprising 1521 OP and 371 YP. At both index and surveillance colonoscopies, YP were more likely to be assigned to a lower RSG (lower grade polyps) compared with OP. However, a greater percentage of YP had their RSG worsen from index to surveillance colonoscopy compared with OP (32.34% vs 25.18%, P < 0.01) (Figure 1). YP were 1.63 times more likely to have RSG worsening compared with OP (95% CI = 1.2–2.2) after controlling for confounding factorsTable 1.: Risk Stratification of Patients Based on Surveillance Colonoscopy Time Recommendations from the US Multi-Society Task Force on Colorectal CancerFigure 1.: Risk Stratification Group (RSG) Changes Between Index and Surveillance Colonoscopies for Older Patients and Younger Patients.Figure 2.: Tier to Tier Risk Stratification Group (RSG) Changes Between Index and Surveillance Colonoscopies for Older Patients and Younger Patients.Most of the RSG worsening was from RSG 1 (normal colonoscopy or small hyperplastic polyps) to RSG 2 (1–2 small tubular adenomas) for both YP and OP (21.02% & 15.06%, respectively) (Figure 2). There were no cases of CRC found in YP and 5 cases of CRC diagnosed in OP on surveillance colonoscopy. CONCLUSION: In our cohort, RSG worsening between index and surveillance colonoscopy was more prevalent in YP compared with OP. Yet, most of the RSG worsening was not clinically meaningful in terms of progression to CRC. This would imply that for the sake of CRC prevention, current surveillance guidelines were indeed appropriate for YP in our cohort of patients. Further study is needed to determine why RSG worsening was higher in YP compared with OP and whether there is any clinical or practical significance to this RSG worsening.

Follow-up Colonoscopy in Patients with Small Nonadvanced Adenomas

Many average-risk patients who undergo screening colonoscopy have a few small tubular adenomas without high-grade dysplasia. Although the 2012

Art in Endoscopy: “The Whale”

This is a sessile serrated lesion after submucosal dye injection, just before endoscopic mucosal resection. The prominent adenomatous nodule reveals progression to cytologic dysplasia, which is a late step in the serrated neoplasia pathway to colorectal cancer. Often, an adenomatous nodule in a polyp is mistaken for a small tubular adenoma by the endoscopist, while the surrounding nondysplastic area of sessile serrated lesion is easily overlooked because of its subtle appearance. This might lead to resection of only the adenomatous nodule, leaving in situ the rest of the lesion.

Does Colon Polyp Surveillance Improve Patient Outcomes?

Colon polyp surveillance now accounts for 25% of all colonoscopies performed. The evidence that colonoscopy surveillance reduces colorectal cancer (CRC) incidence or mortality is weak. The biology of the baseline lesions and quality of the baseline exam are two primary factors contributing to post-colonoscopy CRC. Prior recommendations for surveillance were based largely on the likelihood that patients with adenomas would develop advanced adenomas, a surrogate for CRC. There is now evidence that baseline colonoscopy findings are strongly associated with the risk of incidence or death from CRC. This evidence provides a basis for updated evidence-based recommendations for surveillance. In addition, there is also growing evidence that the quality of the baseline exam is an important predictor of the likelihood of developing post-colonoscopy CRC.

1955 An Ulcerated Lipoma as the Cause of Obscure Gastrointestinal Bleeding

INTRODUCTION: GI bleeding remains one of the most common reasons for GI consultation, with top causes including peptic ulcer disease, erosive disease, angiodysplastic lesions, varices, Mallory Weiss tears, dieulafoy lesions, and malignancy. Obscure GI bleeding (OGIB), defined as recurrent or persistent bleeding or anemia despite negative endoscopic evaluation, makes up 5% of all GI bleed cases. Approximately 75% of OGIB are found to have small bowel lesions. We outline a case of a rare cause of OGIB. CASE DESCRIPTION/METHODS: A 78-year-old female with history of HTN, HLD, CAD, STEMI s/p DES placement, biliary colic s/p cholecystectomy, is referred to GI clinic for symptomatic anemia. She was found to have a hemoglobin of 8 g/dL from baseline 11–12 g/dL. She had been on dual antiplatelet therapy with ticagrelor until 3 months ago, now on aspirin 81 mg. Anemia workup revealed iron deficiency. CT scan negative. Started on po iron with improvement in symptoms. Denied abdominal pain, weight loss, or overt bleeding. No NSAID use. No prior endoscopy or colonoscopy. No family history of GI malignancy. An upper endoscopy and colonoscopy were done. There was antral erythema, otherwise normal EGD. Duodenal and gastric biopsies were negative. Colonoscopy only notable for extensive diverticulosis and a small tubular adenoma. Capsule endoscopy identified active bleeding in the proximal small bowel and a potential submucosal mass. Push enteroscopy revealed a long polypoid lesion extending from the third to fourth portion of the duodenum, approximately 15 mm in width and at least 100 mm in length with visible ulcerated tip. Mucosa was otherwise normal. Endoloop was applied and tissue removed with a hot snare. Pathology resulted in a submucosal lipoma. She was followed with serial blood counts and continued on iron therapy. She is doing well with continued GI follow up. DISCUSSION: This case of an ulcerated lipoma as the cause of an OGIB is among a handful of other case reports and seem to be similarly found in patients on antiplatelet or anticoagulation therapy. Other cases have undergone surgical resection for symptomatic lipomas, however our case suggests that perhaps in those that are able to stop antiplatelet therapy and have a lesion within reach of an enteroscope, resection of the ulcerated portion may be sufficient treatment and may avoid invasive surgery.

232 Numerous Non-Advanced Adenomas Are Not Associated With Metachronous Advanced Neoplasia

INTRODUCTION: Studies using standard definition colonoscopes in the early 2000s demonstrated the risk of metachronous advanced neoplasia (MAN) was doubled in patients with &gt;3 vs 1–2 small tubular adenomas. In the last decade, attention to the importance of adenoma detection rate and the use of high definition (HD) colonoscopes, increases small adenoma detection. We analyzed the association between baseline adenoma features, particularly multiplicity of non-advanced adenomas, on the risk of MAN in patients undergoing HD colonoscopy. METHODS: Patients undergoing first colonoscopy at age ≥50 in the era of HD colonoscopes (≥2006) and follow-up colonoscopy &gt;24 months from baseline exam were identified from the electronic medical record. Exclusions included inflammatory bowel disease, history of colorectal cancer or colon surgery, incomplete colonoscopy, and inadequate bowel preparation. High risk adenoma (HRA) patients included those with an advanced adenoma (≥10 mm in size, adenoma with villous features/high-grade dysplasia) or ≥3 adenomas. Low risk adenoma (LRA) patients included those with 1–2, &lt;10 mm tubular adenomas. The risk of MAN was calculated according to baseline adenoma features. Multivariable analysis compared the risk of MAN between individuals with LRA vs HRA on baseline HD colonoscopy adjusted for interval between first and follow-up colonoscopies. RESULTS: 159,273 patients underwent colonoscopy at age ≥50 in 2006 or later. After exclusions, 3,383 were included. Mean age was 60.5 ± 7.8 and 54.6% were females. The median time interval between the first and follow-up colonoscopy was 59.9 (42.5–66.7) months for the LRA group and 41.8 (36.3–52.2) months for the HRA group. The risk of MAN was 3.8% in individuals with no baseline adenomas; 4% with LRA; and 9.2% with HRA. The risk of MAN in individuals with &gt;3 non-advanced adenomas was 6.3%; 6.1% with 3–4 and 7.4% with &gt;5 non-advanced adenomas (Table 1). On multivariable analysis, the risk of MAN was not different between HRA and LRA based upon the number of non-advanced adenomas: &gt;3 [OR 1.6, (0.7, 3.9)]; 3–4 [OR 1.6, (0.61, 4.0)] and &gt;5 non-advanced adenomas [OR 2.2, (0.27, 17.0)] (Table 2). CONCLUSION: In the contemporary era of HD colonoscopy, compared to LRA patients, patients with ≥3 non-advanced adenomas are not at increased risk of MAN including patients with 3–4 and ≥5 non-advanced adenomas. These data support a longer colonoscopy interval (&gt;5 years) in these individuals.

1504 Case Report: A Rare Case of Community-Acquired Clostridium difficile Infection After Colonoscopy

INTRODUCTION: Clostridium difficile (C.diff) infection (CDI) is commonly related to recent antibiotic use, usually occurring in hospitals and other health care facilities where a significantly higher percentage of people carry the bacteria. Here we reported a rare case of community acquired C.diff 3 days after colonoscopy in a low risk patient without a history of antibiotic use or recent hospitalization. CASE DESCRIPTION/METHODS: A 50-year-old healthy female with no past medical history presented for screening colonoscopy. She tolerated the bowel preparation regimen with polyethylene glycol well. The colonoscopy was unremarkable with one small tubular adenoma removed by snare polypectomy. Patient tolerated the procedure well without any complications. She ate raw blueberry from the local supermarket one day after colonoscopy. Then she presented with watery diarrhea up to 10 times per day with nocturnal symptoms 3 days after colonoscopy. Stool studies were ordered. Diarrhea gradually resolved with hydration and clear liquid diet after 3 days without antibiotics treatment. Stool studies came back with positive C. diff toxins. Patient has no risk factors include recent hospitalization, antibiotic use. She took proton pump inhibitor intermittently a few months prior to colonoscopy. All the other patients had procedures done on the same day in the endoscopy suite had no complications. DISCUSSION: The risk factors of CDI include antibiotics use, advanced age (&gt;65), gastrointestinal surgery, IBD and immunosuppression, etc. The effect of anti-acid use remains unsure because the C. diff spores are acid resistant. Recent studies reported a 7-fold and 13-fold increase in C. diff infection rate after colonoscopy for patients with Crohn's disease and ulcerative colitis compared with non-IBD patients. Another study reported the preoperative use of mechanical bowel preparation was not associated with increased risk of C. diff infection after colectomy. Generally, mechanical bowel preparation and colonoscopy are not risk factors of CDI for a healthy population. This is a rare case with no traditional risk factors acquired CDI by eating raw blueberry 3 days after colonoscopy. Bowel preparation might be a risk factor to disturb the normal gut flora, which increases the risk of CDI. The use of probiotics afterward to prevent C. diff colonization could be a safe and easily adoptable control strategy, but the routine use for prevention or treatment of active infection is not recommended.

The significance of the small adenoma: a longitudinal study of surveillance colonoscopy in an Australian population.

The international guidelines for surveillance following the finding of a small tubular adenoma vary between no surveillance or colonoscopy at 5 or 10 years, whereas surveillance after an advanced adenoma is 3 years. Optimization of surveillance reduces the risk of colorectal cancer (CRC) with efficient use of colonoscopy resources. We assessed the risks of advanced colorectal neoplasia following a baseline finding of a small adenoma compared with advanced adenoma. A retrospective audit was undertaken of patients enrolled in a CRC surveillance program, wherein regular colonoscopies and screening with faecal immunochemical test (FIT) were provided. Patients diagnosed with either small or advanced adenoma followed by at least one surveillance colonoscopy were included. Advanced adenoma included adenomas with features of villous change, size of at least 10 mm, high-grade dysplasia, three or more small tubular adenomas and traditional and sessile serrated adenomas. Subdistribution hazard ratios were calculated for advanced neoplasia (CRC or advanced adenoma). Overall, 378 patients (62.6±11.2 years, 57.9% male) were included, with 44.2% diagnosed with small adenoma and 55.5% with advanced adenoma at baseline. The crude cumulative incidence of advanced neoplasia at first surveillance was 13.2 and 18.5% after small and advanced adenoma (P=0.16) (at 45.9 and 35.6 months, respectively), which became significant for advanced adenoma after adjustment (subdistribution hazard ratio=2.55, 95% confidence interval=1.49-4.35, P<001). A positive FIT was the only independent predictor of advanced neoplasia after a small adenoma at baseline colonoscopy (odds ratio=5.05, 95% confidence interval=1.27-20.02, P=0.02). The risk of advanced neoplasia following a small adenoma was lower than that following an advanced adenoma, but was strongly predicted by a positive FIT. Reducing frequency of colonoscopy while providing regular FIT might be a more efficient use of resources for this population.

Melanosis Coli

A 59-year-old man taking an oral Aloe vera supplement and with a history of colonic polyps 6 years prior, presented for a surveillance colonoscopy. From the anal verge to the ileocecal valve the colonic mucosa was diffusely darkly pigmented, consistent with marked melanosis coli. Melanosis coli is a benign condition in which macrophages in the colonic lamina propria are stained by lipofuscin pigment as a result of phagocytosis of apoptotic epithelial cells caused by exposure to plant-based anthraquinone laxatives, usually over a period of at least 2–3 months. Senna, cascara, aloe, and rhubarb supplements are some of the most common sources of anthraquinones. Neither the small bowel nor colonic polyps are stained as a result of anthraquinone exposure, as can be seen in photographs of the ileocecal valve (Figure A) and polyps (Figures B and C). The sharp contrast produced by the lack of color change in neoplastic polyp tissue can render otherwise subtle polyps more readily visible. In this patient the presence of melanosis coli aided in the detection and removal of a 10-mm flat cecal tubular adenoma and 10 additional small sessile tubular adenomas.

Risk factors for advanced duodenal and ampullary adenomatosis in familial adenomatous polyposis: a prospective, single-center study.

Background and study aims To determine the clinical features associated with advanced duodenal and ampullary adenomas in familial adenomatous polyposis. Secondarily, we describe the prevalence and clinical significance of jejunal polyposis. Patients and methods This is a single center, prospective study of 62 patients with familial adenomatous polyposis. Duodenal polyposis was classified according to Spigelman and ampullary adenomas were identified. Patients with Spigelman III and IV duodenal polyposis underwent balloon assisted enteroscopy. Predefined groups according to Spigelman and presence or not of ampullary adenomas were related to the clinical variables: gender, age, family history of familial adenomatous polyposis, type of colorectal surgery, and type of colorectal polyposis. Results Advanced duodenal polyposis was present in 13 patients (21 %; 9 male) at a mean age of 37.61 ± 13.9 years. There was a statistically significant association between family history of the disease and groups according to Spigelman ( P = 0.03). Seven unrelated patients (6 male) presented ampullary adenomas at a mean age of 36.14 ± 14.2 years. The association between ampullary adenomas and extraintestinal manifestations was statistically significant in multivariate analysis ( P = 0.009). Five endoscopic types of non-ampullary adenoma were identified, showing that lesions larger than 10 mm or with a central depression presented foci of high grade dysplasia. Among 28 patients in 12 different families, a similar Spigelman score was identified; 10/12 patients (83.3 %) who underwent enteroscopy presented small tubular adenomas with low grade dysplasia in the proximal jejunum. Conclusions Advanced duodenal polyposis phenotype may be predictable from disease severity in a first-degree relative. Ampullary adenomas were independently associated with the presence of extraintestinal manifestations.

Presence of Villous Histology in Otherwise Low-Risk Small Adenomas Does not Significantly Increase Risk of Advanced Neoplasia Upon Surveillance: 2017 Presidential Poster Award

Introduction: The USMSTF recommends shortened surveillance intervals in the presence of any adenoma >10mm in size, >3 adenomas in number, high-grade dysplasia (HGD) or villous histology. The risk of metachronous advanced neoplasia (MAN) when villous histology or HGD is found in isolated small polyps has not been well described. We aimed to assess rates of MAN based on the presence of villous histology or HGD in small adenomas compared to small tubular adenomas in its absence. Methods: Colonoscopy and pathology reports from all patients found to have 1 or 2 adenomas whose maximum size was <10 mm from 2005 and 2011 at two medical centers were reviewed. These patients were stratified into three groups based on initial colonoscopy findings as follows (1) isolated low-risk adenoma [LRA], (2) small adenoma by size with presence of villous histology [small villous], and (3) small adenoma by size with presence of HGD [small HGD]. Patients with serrated lesions were excluded. Concordance in interpretation of villous histology in small polyps between two GI pathologists was assessed through random review of 50 cases with both pathologists blinded to the other's interpretation. Results: There were 3,185 patients with 1 or 2 small tubular adenomas found on index colonoscopy. The rate of villous histology was 2% (55/2,685) in adenomas <5mm compared to 12% (60/500) in adenomas 6-9mm in size, thus an overall rate of 3.6%. Of these, there were 790 patients with follow-up colonoscopy data available. The rate of MAN in the small villous group (9/79, 11.4%) is similar to the conventional LRA group (56/697, 8%; P=0.287). Conversely, the rate of MAN in the small HGD group (4/14, 28.6%) is significantly greater compared to the LRA group (P=0.024). Polyp size >10 mm was the predominant defining feature of AN at surveillance in all three groups. There was pathology concordance in 37 out of 50 cases with a Kappa score of 0.553 (SE=0.123). Conclusion: The rate of advanced neoplasia on follow-up in patients with small adenomas containing villous histology appears comparable to patients with low-risk adenomas in their absence. Villous histology appears to occur infrequently in diminutive polyps. Given the lack of evidence that isolated villous features portends significant risk and the variation in pathology interpretation, we question the utility of describing villous features in small polyps, especially when diminutive, and making surveillance recommendations based on this determination.Table: No Caption available.

Therapy-associated Polyposis: Additional Cases in Support of This Novel Form of Acquired Gastrointestinal Polyposis

Childhood cancer survivors who received abdominopelvic XRT and/or chemotherapy, are at higher risk for gastrointestinal cancers in adulthood. Recognized hereditary polyposis syndromes that typically present in early to mid-adulthood and lead to gastrointestinal cancers include familial adenomatous polyposis (FAP), attenuated FAP, MYH-associated polyposis, and hamartomatous polyposis syndromes. Yurgelun et al. published a series of 5 childhood cancer survivors who developed gastrointestinal polyposis later in life. None of these patients had detectable APC or MYH mutations. We report two more cases of intestinal polyposis in childhood cancer survivors whose genetic testing and family history were not consistent with a hereditary syndrome. Our cases add to the evidence that chemotherapy and/or radiation exposure may be a risk factor for acquired gastrointestinal polyposis. Case 1 was diagnosed with stage IV adrenal neuroblastoma at age 2, treated with cyclophosphamide and whole body XRT. At 29, he had rectal bleeding with a colonoscopy revealing multiple tubulovillous adenomas >1 cm, one with high grade dysplasia (HGD) and one with multiple foci of HGD and intramucosal adenocarcinoma. He had a sigmoidectomy. Surveillance has found two small colonic tubular adenomas and a 3 cm duodenal serrated adenoma. At 30, he was diagnosed with papillary thyroid microcarcinomas. Case 2 was diagnosed with stage IIIA Hodgkin's lymphoma at age 10, treated with MOPP chemotherapy and mantle/splenic pedicle radiation therapy (40 Gy). Screening colonoscopy at age 45 showed over 30 tubular adenomas and 40 sessile serrated adenomas. He had a right hemicolectomy. Surveillance every 6 months has found more tubular adenomas. At 47, he developed bilateral papillary thyroid cancer. Both patients had no significant family history of gastrointestinal polyps/cancers and genetic testing was negative for APC and MYH mutations. We present two cases consistent with an acquired gastrointestinal polyposis syndrome. Our cases are similar to the 5 patients published by Yurgelun et al, and add to the evidence that childhood exposure to chemotherapy and/or XRT may result in acquired gastrointestinal polyposis in adulthood. The extracolonic and future gastrointestinal polyp risks in these patients may differ from established hereditary polyposis syndromes. Establishing acquired therapy-associated polyposis as a separate entity has important implications for future surveillance in these patients.