Risk factors for advanced colorectal neoplasia and colorectal cancer detected at surveillance: a nationwide study in the modern era.

AIM: Recommendations for surveillance after colonoscopy are based on risk factors for metachronous advanced colorectal neoplasia (AN) and colorectal cancer (CRC). The value of these risk factors remains unclear in populations enriched by individuals with a positive faecal immunochemical test and were investigated in a modern setting. METHODS AND RESULTS: This population-based cohort study included all individuals in the Netherlands of ≥55 years old with a first adenoma diagnosis in 2015. A total of 22,471 patients were included. Data were retrieved from the Dutch Nationwide Pathology Databank (Palga). Primary outcomes were metachronous AN and CRC. Patient and polyp characteristics were evaluated by multivariable Cox regression analyses. During follow-up, 2416 (10.8%) patients were diagnosed with AN, of which 557 (2.5% from the total population) were CRC. Adenomas with high-grade dysplasia (hazard ratio [HR] 1.60, 95% confidence interval [CI] 1.40-1.83), villous histology (HR 1.91, 95% CI 1.59-2.28), size ≥10 mm (HR 1.12, 95% CI 1.02-1.23), proximal location (HR 1.12, 95% CI 1.02-1.23), two or more adenomas (HR 1.28, 95% CI 1.16-1.41), and serrated polyps ≥10 mm (HR 1.67, 95% CI 1.42-1.97) were independent risk factors for metachronous AN. In contrast, only adenomas with high-grade dysplasia (HR 2.49, 95% CI 1.92-3.24) were an independent risk factor for metachronous CRC. CONCLUSIONS: Risk factors for metachronous AN and CRC were identified for populations with access to a faecal immunochemical test (FIT)-based screening programme. If only risk factors for metachronous CRC are considered, a reduction in criteria for surveillance seems reasonable.

Deficient mismatch repair screening of advanced adenomas in the population screening program for colorectal cancer is not effective.

AIM: Currently, screening of colorectal cancers (CRC) by assessing mismatch repair deficiency (dMMR) or microsatellite instability (MSI) is used to identify Lynch syndrome (LS) patients. Advanced adenomas are considered immediate precursor lesions of CRC. In this study we investigate the relevance of screening of advanced adenomas for LS in population screening. METHODS AND RESULTS: Advanced adenomas (n = 1572) were selected from the Dutch colorectal cancer population screening programme, based on one or more of the criteria: tubulovillous (n = 848, 54%) or villous adenoma (n = 118, 7.5%), diameter ≥ 1 cm (n = 1286, 82%) and/or high-grade dysplasia (n = 176, 11%). In 86 cases (5%), all three criteria were fulfilled at the same time. MMR-IHC and/or MSI analyses were performed on all cases. Only five advanced adenomas (0.3%) showed dMMR and MSI, including two cases with hypermethylation. In at least two patients a germline event was suspected based on allelic frequencies. No pathogenic explanation was found in the last case. CONCLUSION: Timely testing of precursor lesions would be preferable to detect new LS patients before CRC development. However, standard assessment of dMMR of advanced adenomas from the population screening is not effective.

High yield of surveillance in patients diagnosed with constitutional mismatch repair deficiency.

BACKGROUND: Constitutional mismatch repair deficiency (CMMRD) is a rare autosomal recessively inherited syndrome that is caused by biallelic pathogenic variants of the mismatch repair genes. It is characterised by the development of multiple tumours in the first and second decade of life including brain, gastrointestinal and haematological tumours often resulting in early death. In order to improve the prognosis of these patients, the European collaborative group 'care for CMMRD' developed a surveillance programme in 2014 and established a registry of patients with CMMRD in Paris. The aim of the study was to evaluate the outcome of this programme. METHODS: Twenty-two patients with a definitive diagnosis of CMMRD and with at least one follow-up study were selected from the registry. Medical data on the outcome of surveillance were collected from these patients. RESULTS: During a mean follow-up of 4 years, the programme detected eight malignant tumours including three brain tumours, three upper gastrointestinal cancers and two colorectal cancers. Most tumours could successfully be treated. In addition, many adenomas were detected in the duodenum, and colorectum and subsequently removed. Seven patients developed a symptomatic malignancy, including two brain tumours, one small bowel cancer and four haematological malignancies. At the end of the follow-up, 16 out of 22 patients (73%) who participated in the surveillance programme were still alive. CONCLUSION: The study suggests a beneficial effect of surveillance of the digestive tract and brains.

Detection and Yield of Colorectal Cancer Surveillance in Adults with PTEN Hamartoma Tumour Syndrome.

Colorectal cancer surveillance (CCS) with colonoscopy every five years is advised for PTEN Hamartoma Tumour Syndrome (PHTS) patients aged ≥40 due to an increased colorectal cancer (CRC) risk. However, data to support CCS guidelines are scarce and available CRC risks are low (0-5% at age 50) and likely overestimated. We aimed to assess the detection and yield of CCS for PHTS patients without a CRC history. A retrospective cohort study including PHTS patients aged ≥40 with CCS at a PHTS expertise centre between 2011 and 2022. Adenomas with a ≥10 mm size, (tubulo)villous histology, or high-grade dysplasia were considered advanced. During 67 follow-up years, 37 patients (median age 47 years) underwent 61 colonoscopies. CCS yielded no CRCs. Adenomas were diagnosed in 13/37 (35%) patients during 23/100 colonoscopies (95% CI: 14-36), including one advanced adenoma. Baseline adenoma detection rates were similar to follow-up and higher in patients aged above 50 (50/100, 95% CI: 24-76) vs. age 50 or below (11/100, 95% CI: 3-30; p = 0.021). The low CRC and advanced adenoma yield allow for a more personalised surveillance program. Following our findings combined with literature on CRC risk and progression, we suggest starting CCS at age 40 with variable follow-up intervals between 1 and 10 years depending on previous colonoscopy findings.

The Workgroup Serrated Polyps and Polyposis (WASP) classification for optical diagnosis of colorectal diminutive polyps with iScan and the impact of the revised World Health Organization (WHO) criteria.

BACKGROUND AND AIMS: The Workgroup Serrated Polyps and Polyposis (WASP) developed criteria for optical diagnosis of colorectal polyps. The aims of this study were: (1) to improve optical diagnosis of diminutive colorectal polyps, especially SSLs, after training endoscopists in applying WASP criteria on videos of polyps obtained with iScan and (2) to evaluate if the WASP criteria are still useful when polyps are pathologically revised according to the World Health Organization (WHO) 2019 criteria. METHODS: Twenty-one endoscopists participated in a training session and predicted polyp histology on 30 videos of diminutive polyps, before and after training (T0 and T1 ). After three months, they scored another 30 videos (T2 ). Primary outcome was overall diagnostic accuracy (DA) at T0 , T1 and T2 . Polyps were histopathologically classified according to the WHO 2010 and 2019 criteria. RESULTS: Overall DA (both diminutive adenomas and SSLs) significantly improved from 0.58 (95% CI 0.55-0.62) at T0 to 0.63 (95% CI 0.60-0.66, p = 0.004) at T1 . For SSLs, DA did not change with 0.51 (95% CI 0.46-0.56) at T0 and 0.55 (95% CI 0.49-0.60, p = 0.119) at T1 . After three months, overall DA was 0.58 (95% CI 0.54-0.62, p = 0.787, relative to T0 ) while DA for SSLs was 0.48 (95% CI 0.42-0.55, p = 0.520) at T2 . After pathological revision according to the WHO 2019 criteria, DA of all polyps significantly changed at all time points. CONCLUSION: A training session in applying WASP criteria on endoscopic videos made with iScan did not improve endoscopists' long-term ability to optically diagnose diminutive polyps. The change of DA following polyp revision according to the revised WHO 2019 criteria suggests that the WASP classification may need revision.

Associations of Pathogenic Variants in MLH1, MSH2, and MSH6 With Risk of Colorectal Adenomas and Tumors and With Somatic Mutations in Patients With Lynch Syndrome.

BACKGROUND & AIMS: Lynch syndrome is caused by variants in DNA mismatch repair (MMR) genes and associated with an increased risk of colorectal cancer (CRC). In patients with Lynch syndrome, CRCs can develop via different pathways. We studied associations between Lynch syndrome-associated variants in MMR genes and risks of adenoma and CRC and somatic mutations in APC and CTNNB1 in tumors in an international cohort of patients. METHODS: We combined clinical and molecular data from 3 studies. We obtained clinical data from 2747 patients with Lynch syndrome associated with variants in MLH1, MSH2, or MSH6 from Germany, the Netherlands, and Finland who received at least 2 surveillance colonoscopies and were followed for a median time of 7.8 years for development of adenomas or CRC. We performed DNA sequence analyses of 48 colorectal tumors (from 16 patients with mutations in MLH1, 29 patients with mutations in MSH2, and 3 with mutations in MSH6) for somatic mutations in APC and CTNNB1. RESULTS: Risk of advanced adenoma in 10 years was 17.8% in patients with pathogenic variants in MSH2 vs 7.7% in MLH1 (P < .001). Higher proportions of patients with pathogenic variants in MLH1 or MSH2 developed CRC in 10 years (11.3% and 11.4%) than patients with pathogenic variants in MSH6 (4.7%) (P = .001 and P = .003 for MLH1 and MSH2 vs MSH6, respectively). Somatic mutations in APC were found in 75% of tumors from patients with pathogenic variants in MSH2 vs 11% in MLH1 (P = .015). Somatic mutations in CTNNB1 were found in 50% of tumors from patients with pathogenic variants in MLH1 vs 7% in MSH2 (P = .002). None of the 3 tumors with pathogenic variants in MSH6 had a mutation in CTNNB1, but all had mutations in APC. CONCLUSIONS: In an analysis of clinical and DNA sequence data from patients with Lynch syndrome from 3 countries, we associated pathogenic variants in MMR genes with risk of adenoma and CRC, and somatic mutations in APC and CTNNB1 in colorectal tumors. If these findings are confirmed, surveillance guidelines might be adjusted based on MMR gene variants.

Constitutional mismatch repair deficiency as a differential diagnosis of neurofibromatosis type 1: consensus guidelines for testing a child without malignancy.

Constitutional mismatch repair deficiency (CMMRD) is a rare childhood cancer predisposition syndrome caused by biallelic germline mutations in one of four mismatch-repair genes. Besides very high tumour risks, CMMRD phenotypes are often characterised by the presence of signs reminiscent of neurofibromatosis type 1 (NF1). Because NF1 signs may be present prior to tumour onset, CMMRD is a legitimate differential diagnosis in an otherwise healthy child suspected to have NF1/Legius syndrome without a detectable underlying NF1/SPRED1 germline mutation. However, no guidelines indicate when to counsel and test for CMMRD in this setting. Assuming that CMMRD is rare in these patients and that expected benefits of identifying CMMRD prior to tumour onset should outweigh potential harms associated with CMMRD counselling and testing in this setting, we aimed at elaborating a strategy to preselect, among children suspected to have NF1/Legius syndrome without a causative NF1/SPRED1 mutation and no overt malignancy, those children who have a higher probability of having CMMRD. At an interdisciplinary workshop, we discussed estimations of the frequency of CMMRD as a differential diagnosis of NF1 and potential benefits and harms of CMMRD counselling and testing in a healthy child with no malignancy. Preselection criteria and strategies for counselling and testing were developed and reviewed in two rounds of critical revisions. Existing diagnostic CMMRD criteria were adapted to serve as a guideline as to when to consider CMMRD as differential diagnosis of NF1/Legius syndrome. In addition, counselling and testing strategies are suggested to minimise potential harms.

Features of incident colorectal cancer in Lynch syndrome.

BACKGROUND AND OBJECTIVE: Despite intensive colonoscopic surveillance, a substantial proportion of Lynch syndrome (LS) patients develop colorectal cancer (CRC). The aim of this study was to characterize incident CRC in LS patients. METHODS: All patients diagnosed with incident CRC after start of colonoscopic surveillance were identified in the Dutch LS Registry of 905 patients. A retrospective analysis of patient records was carried out for patient characteristics, survival, CRC characteristics and findings of previous colonoscopy. RESULTS: Seventy-one patients (7.8%) were diagnosed with incident CRC. Median interval between incident CRC diagnosis and previous colonoscopy was 23.8 (range 6.7-45.6) months. Median tumor diameter was 2.5 cm, and 17% of the tumors were sessile or flat. Most patients (83%) had no lymph node metastases. There was no association between tumor size and colonoscopy interval or lymph node status. Most patients (65%) had no adenomas during previous colonoscopy. Two patients (2.8%) eventually died from metastatic CRC. CONCLUSION: The high frequency of incident CRC in LS likely results from several factors. Our findings lend support to the hypothesis of fast conversion of adenomas to CRC, as 65% of patients had no report of polyps during previous colonoscopy. High-quality colonoscopies are essential, especially as tumors and adenomas are difficult to detect because of their frequent non-polypoid appearance. Early detection due to surveillance as well as the indolent growth of CRC, as demonstrated by the lack of lymph node metastases, contributes to the excellent survival observed.

No Difference in Colorectal Cancer Incidence or Stage at Detection by Colonoscopy Among 3 Countries With Different Lynch Syndrome Surveillance Policies.

BACKGROUND & AIMS: Patients with Lynch syndrome are at high risk for developing colorectal cancer (CRC). Regular colonoscopic surveillance is recommended, but there is no international consensus on the appropriate interval. We investigated whether shorter intervals are associated with lower CRC incidence and detection at earlier stages by comparing the surveillance policies in Germany, which evaluates patients by colonoscopy annually, in the Netherlands (patients evaluated at 1-2-year intervals), and Finland (patients evaluated at 2-3-year intervals). METHODS: We collected data from 16,327 colonoscopic examinations (conducted from 1984 through 2015) of 2747 patients with Lynch syndrome (pathogenic variants in the MLH1, MSH2, or MSH6 genes) from the German HNPCC Consortium, the Dutch Lynch Syndrome Registry, and the Finnish Lynch Syndrome Registry. Our analysis included 23,309 person-years of cumulative observation time. Time from the index colonoscopy to incident CRC or adenoma was analyzed using the Kaplan-Meier method; groups were compared using the log-rank test. We performed multivariable Cox regression analyses to identify factors associated with CRC risk (diagnosis of CRC before the index colonoscopy, sex, mutation, age, and presence of adenoma at the index colonoscopy). RESULTS: The 10-year cumulative CRC incidence ranged from 4.1% to 18.4% in patients with low- and high-risk profiles, respectively, and varied with age, sex, mutation, and prior detection of CRC or adenoma. Observed colonoscopy intervals were largely in accordance with the country-specific recommendations. We found no significant differences in cumulative CRC incidence or CRC stage at detection among countries. There was no significant association between CRC stage and time since last colonoscopy. CONCLUSIONS: We did not find a significant reduction in CRC incidence or stage of detection in Germany (annual colonoscopic surveillance) than in countries with longer surveillance intervals (the Netherlands, with 1-2-year intervals, and Finland, with 2-3-year intervals). Overall, we did not find a significant association of the interval with CRC risk, although age, sex, mutation, and prior neoplasia were used to individually modify colonoscopy intervals. Studies are needed to develop and validate risk-adapted surveillance strategies and to identify patients who benefit from shorter surveillance intervals.

Colorectal Cancer Risk in Patients With Lynch Syndrome and Inflammatory Bowel Disease.

Lynch syndrome and inflammatory bowel diseases (IBD) are associated with an increased risk of colorectal cancer (CRC). However, it is not clear whether the risk of CRC is even higher for patients with a combination of Lynch syndrome and IBD. We investigated the risk for CRC in this subgroup by establishing a Lynch syndrome cohort from the Radboud University Medical Center (Nijmegen, The Netherlands) and the Academic Medical Center (Amsterdam, The Netherlands). Patients with heterozygous germline mutations in MLH1, MSH2 (and EPCAM deletion-mediated MSH2 methylation), MSH6, or PMS2 who were tested and/or treated from 1998 through 2014 were included. Patients who developed IBD were identified by linkage of this cohort to the Dutch nationwide Pathology Registry (PALGA). Subsequently, we compared the risk of CRC between Lynch syndrome patients with IBD and without IBD. Of 1046 patients with Lynch syndrome, 15 developed IBD (1.4%). Patients with Lynch syndrome and IBD were significantly younger (median age, 38.0 y) than patients with Lynch syndrome without IBD (median age, 52.0 y; P = .001). Nevertheless, a similar proportion of patients in each group developed CRC: 4 of the 15 patients (26.7%) with Lynch syndrome and IBD compared with 311 of the 1031 patients (30.2%) with Lynch syndrome without IBD. Patients with Lynch syndrome and IBD developed CRC at a younger age (median age, 36.0 y) than patients with Lynch syndrome without IBD (median age, 46.0 y; P = .045). However, the cumulative incidence of CRC was similar between groups (P = .121). All patients with Lynch syndrome and IBD who developed CRC had ulcerative colitis, producing a higher cumulative incidence of CRC for this IBD subgroup (P < .001). In conclusion, patients with Lynch syndrome and IBD develop CRC risk at a younger age than patients without IBD; patients with ulcerative colitis are at especially high risk.

[A man with multiple mucosal lesions and pancytopenia]. / Een man met pancytopenie en mucosale afwijkingen.

A 57-year-old man came to the Emergency Department because of painful oral ulcers and skin lesions. He used methotrexate because of psoriasis, but he stopped using folic acid. Laboratory tests showed signs of dehydration and pancytopenia. We made the diagnosis 'methotrexate-intoxication'.

Patients' perception of colonoscopy: patients with inflammatory bowel disease and irritable bowel syndrome experience the largest burden.

BACKGROUND: Colonoscopy is a frequently performed procedure worldwide with a negative perception, leading to reluctance to undergo the procedure. Perceptions could differ depending on the specific indication for the colonoscopy. AIMS: To compare patient satisfaction with the colonoscopy procedure between five different patient groups: inflammatory bowel disease (IBD), familial predisposition for cancer, adenoma/carcinoma surveillance, symptoms suggestive of cancer, and irritable bowel syndrome (IBS). METHODS: A prospective questionnaire study was carried out in two regional hospitals and two tertiary teaching hospitals in the Netherlands. A total of 797 consecutive patients scheduled for colonoscopy between October 2009 and June 2010, 146 (18%) IBD, 153 (19%) adenoma or carcinoma surveillance, 104 (13%) familial predisposition, 280 (35%) symptoms suggestive of cancer, and 114 (14%) IBS-like symptoms, were included. Two questionnaires were administered: one on the day of the procedure and another 6 weeks after the procedure. The main outcome measurements were embarrassment, pain, burden, most burdensome aspect, and overall level of satisfaction. RESULTS: Patients with IBD and IBS reported significantly more embarrassment and burden from the bowel preparation phase (P=0.040 and 0.018, respectively) and more pain during the colonoscopy procedure (P=0.018). This difference in pain was also observed when adjusting for volume of sedation administered, familiarity with the endoscopist, duration of the colonoscopy, or whether or not an intervention was performed. All patient groups were less satisfied with the procedure at 6 weeks than directly after the colonoscopy; they recalled more embarrassment and burden, but less pain. CONCLUSION: Patient groups, defined by indication for colonoscopy, experience the colonoscopy procedure differently.

A prospective study of bowel preparation for colonoscopy with polyethylene glycol-electrolyte solution versus sodium phosphate in Lynch syndrome: a randomized trial.

Lynch gene carriers undergo regular surveillance colonoscopies. Polyethylene glycol-electrolyte solution (PEG) is routinely prescribed for bowel cleansing, but often poorly tolerated by patients. Sodium phosphate (NaP) may be an alternative. Prospective and random comparison of bowel preparation with PEG and NaP on colon cleansing and patients' acceptance. Patients, who previously underwent a colonoscopy, were invited to participate and randomly assigned to either PEG or NaP. They were asked to fill in a questionnaire about preparation tolerability and future preferences. The endoscopist filled out a report about the quality of colon cleansing. 125 Patients were included in the study. Nine (7%) were excluded because of missing data. The remaining 116 patients (53 PEG and 63 NaP) were included in the analysis. Baseline characteristics did not differ between groups. Before colonoscopy 20 (38%) patients using PEG experienced the preparation almost intolerable, in contrast to 7(11%) of those using NaP (P = 0.001). Eleven patients in the PEG group and 48 in the NaP group would prefer NaP in the future. The colonoscopy was poorly tolerated in 17% of the individuals in both groups (P = 0.963). The endoscopist observed a more than 75% clean colon in 83% of patients on PEG and in 71% of patients on NaP (P = 0.076), however the coecum (P = 0.025) and ascending colon was cleaner after PEG. Lynch patients tolerated NaP better and preferred this formula for future bowel preparation. Colon cleansing was suboptimal with both treatments with a tendency towards a cleaner proximal colon with PEG.

Management of sporadic duodenal adenomas and the association with colorectal neoplasms: a retrospective cohort study.

GOALS: To evaluate management, outcome, and follow-up of patients with sporadic duodenal adenomas and assess the presence of colorectal neoplasms. BACKGROUND: With the widespread use of esophagogastroduodenoscopy, an increasing number of sporadic duodenal adenomas are diagnosed. An optimal algorithm for management has not been fully defined. Accumulating data suggest an association with colorectal neoplasms. STUDY: Patients diagnosed with sporadic duodenal adenomas at our institute from 1986 until 2008 were retrospectively reviewed. Data were collected from medical records. RESULTS: Fifty-four patients (28 men, 52%) were diagnosed with a sporadic duodenal adenoma at a median age of 59 years (range, 27 to 84 y); 33 patients (61%) underwent endoscopic or surgical intervention, 5 (9%) were only followed endoscopically, and 16 (30%) underwent no intervention or follow-up. Complete endoscopic removal was accomplished in at least 81% of cases, and no complications were reported; surgical intervention was complicated in 4 patients, with 1 resulting in death. Adenoma recurrence was 20% at a median follow-up of 18 months (range, 4 to 54 mo), but no carcinoma developed. Colorectal neoplasms were found in 16 of 29 patients (55%) who underwent colonoscopy, including 2 cancers (7%), 7 advanced adenomas (24%), and 7 nonadvanced adenomas (24%). CONCLUSIONS: Although no consistent approach to management of sporadic duodenal adenomas was followed, no duodenal carcinoma developed during the follow-up. Endoscopic intervention is preferred over surgical intervention, whenever possible. Once complete removal is ascertained, there is no strict indication for regular follow-up esophagogastroduodenoscopy, especially in elderly patients or patients with relevant comorbidity. Colonoscopic assessment is warranted in all patients diagnosed with sporadic duodenal adenomas.

Does (supra)gastric belching trigger recurrent hiccups?

Twenty-four hours multichannel intraesophageal impedance and pH monitoring in a patient who suffered from recurrent hiccups for more than a year revealed frequent supragastric belching and pathological oesophageal acid exposure. Furthermore, a temporal relationship between the start of a hiccup episode and gastric belching was observed. The data support the hypothesis that there is an association between supragastric belching, persistent recurrent hiccups and gastro-oesophageal reflux disease, and that gastric belching may evoke hiccup attacks.

One to 2-year surveillance intervals reduce risk of colorectal cancer in families with Lynch syndrome.

BACKGROUND & AIMS: Two percent to 4% of all cases of colorectal cancer (CRC) are associated with Lynch syndrome. Dominant clustering of CRC (non-Lynch syndrome) accounts for 1%-3% of the cases. Because carcinogenesis is accelerated in Lynch syndrome, an intensive colonoscopic surveillance program has been recommended since 1995. The aim of the study was to evaluate the effectiveness of this program. METHODS: The study included 205 Lynch syndrome families with identified mutations in one of the mismatch repair genes (745 mutation carriers). We also analyzed data from non-Lynch syndrome families (46 families, 344 relatives). Patients were observed from January 1, 1995, until January 1, 2009. End points of the study were CRC or date of the last colonoscopy. RESULTS: After a mean follow-up of 7.2 years, 33 patients developed CRC under surveillance. The cumulative risk of CRC was 6% after the 10-year follow-up period. The risk of CRC was higher in carriers older than 40 years and in carriers of MLH1 and MSH2 mutations. After a mean follow-up of 7.0 years, 6 cases of CRC were detected among non-Lynch syndrome families. The risk of CRC was significantly higher among families with Lynch syndrome, compared with those without. CONCLUSIONS: With surveillance intervals of 1-2 years, members of families with Lynch syndrome have a lower risk of developing CRC than with surveillance intervals of 2-3 years. Because of the low risk of CRC in non-Lynch syndrome families, a less intensive surveillance protocol can be recommended.

Noninvasive monitoring of colonic carcinogenesis: feasibility of [(18)F]FDG-PET in the azoxymethane model.

BACKGROUND: Azoxymethane (AOM) is a potent carcinogen that induces colorectal cancer and adenomas in rats. [(18)F]FDG-PET is a molecular imaging technique that is based on the elevated uptake and retention of radiolabeled glucose. At present, it is unknown at which stage FDG accumulation occurs during the adenoma carcinoma sequence. To address this issue, we studied the FDG uptake in AOM-induced rat colorectal adenocarcinoma (CRC) and correlated this with histopathological findings. METHODS: Seventy Fischer 344 rats were injected with AOM. Terminal autopsy took place 20-38 weeks after the first AOM injection. After [(18)F]FDG PET scanning, the rats were sacrificed, tissue [(18)F]FDG uptake was measured, followed by histopathological examination. RESULTS: Macroscopic examination revealed 21 tumors (7 located in the small bowel and 14 in the colon) in 19 rats. On histological examination, we found 10 colonic adenocarcinomas (the first being observed at Week 22) and 7 adenocarcinoma in the small bowel. In total, seven colon adenomas were found in five rats, six of which expressed high-grade dysplasia. The [(18)F]FDG accumulation in small intestine carcinomas was well beyond background accumulation (P<.0001). On PET scanning, two rats showed focal accumulation of the abdominal area, corresponding to small intestine carcinomas. CONCLUSION: Adenocarcinomas had a significantly higher [(18)F]FDG uptake than background bowel uptake. [(18)F]FDG uptake was lower in adenomas than in carcinomas. These data suggest that the AOM model allows the evaluation of intervention strategies with [(18)F]FDG uptake as a valid outcome measure.

Ability of FDG-PET to detect all cancers in patients with familial adenomatous polyposis, and impact on clinical management.

PURPOSE: Familial adenomatous polyposis (FAP) is characterised by colonic and duodenal adenomatous polyps that carry a risk of malignant transformation. Malignant degeneration of duodenal adenomas is difficult to detect. We speculated that 2-((18)F)-fluoro-2-deoxy-D: -glucose positron emission tomography (FDG-PET) might be able to detect early duodenal cancer in FAP. Accordingly, we investigated the role of FDG-PET in the management of FAP patients. METHODS: FDG-PET was performed in 24 FAP patients. Eight had advanced duodenal adenomas (Spigelman IV), including two patients with duodenal cancer. Scans were defined as positive on the basis of focal FDG accumulation. RESULTS: Pathological FDG accumulation was absent in 19 of 24 patients. All six patients with Spigelman IV duodenal adenomas (without cancer) were negative; two of these underwent a duodenectomy and pathological examination did not reveal duodenal cancer. In five patients, FDG-PET revealed significant uptake, in the duodenum (2), lower abdomen (1), lung (1) and multiple sites in the abdomen (1). These hot spots correlated with duodenal cancer (2), abdominal metastasis (1) and sclerosing haemangioma of the lung (1). We failed to make a histopathological diagnosis in the single patient with multiple intra-abdominal sites of FDG uptake. None of the patients from the FDG-PET-negative group developed cancer during follow-up (mean 2.8 years). CONCLUSION: FDG-PET detected all the cancers present, and none of the patients with negative FDG-PET developed cancer. This suggests that positive FDG-PET in FAP patients should lead to further examinations to rule out cancer. In patients with negative FDG-PET a more conservative approach seems justified.

FDG-PET in the detection of early pancreatic cancer in a BOP hamster model.

BACKGROUND: The prognosis of pancreatic cancer (PC) is highly dependent on the stage of the disease, and early recognition improves survival. Positron emission tomography (PET) using (18)F-fluoro-2-deoxyglucose ([(18)F]FDG) has been established as an important clinical tool for PC diagnosis, but it is not known whether FDG-PET detects premalignant stages of PC. We speculate that [(18)F]FDG uptake precedes the onset of PC in a hamster model. We used the N-nitrosobis(2-oxopropyl)amine (BOP) model, as these animals consistently develop PC within 20 weeks after first injection. METHODS: Male Syrian hamsters were injected once a week with 10 mg BOP/kg body weight for 10 consecutive weeks. Terminal autopsy took place in groups of five hamsters from 4 weeks until 28 weeks after first BOP injection. After an 8-h fast, hamsters were injected with [(18)F]FDG and sacrificed 1 h after [(18)F]FDG injection. The pancreata were histopathologically examined, and the [(18)F]FDG uptake was determined and expressed as percentage of the injected dose per gram tissue (%ID/g). RESULTS: Seven of 55 hamsters developed macroscopic signs of tumor. Histopathological examination revealed PC in 13 hamsters. [(18)F]FDG uptake increased gradually with time and was significantly higher in the group with PC compared to the group without PC. CONCLUSION: [(18)F]FDG accumulates preferentially in PC, and pancreata exposed to BOP showed a gradual increase in [(18)F]FDG accumulation.

2-(18F)-fluoro-2-deoxy-D-glucose positron emission tomography detects clinical relevant adenomas of the colon: a prospective study.

PURPOSE: 2-(18F)-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) is a noninvasive imaging technique used clinically to detect malignant tumors. FDG-PET has been established as a tool for diagnosis of recurrent or metastatic colorectal carcinoma. Several case series suggest that FDG-PET also detects larger adenomas. The goal of this study was to investigate whether FDG-PET is able to detect colonic adenomas. PATIENTS AND METHODS: FDG-PET was performed in 100 consecutive patients in whom colonic adenomas were suspected on barium enema (n = 47) or sigmoidoscopy (n = 53). A positive scan was defined as focal large bowel FDG accumulation. FDG-PET was followed in all cases by colonoscopy, and removed adenomas were examined histopathologically. RESULTS: Colonoscopy confirmed the presence of adenomas in 68 of 100 patients. In 35 patients, there was focal FDG accumulation at site of the adenoma. The sensitivity of FDG-PET increased with adenoma size (21%, adenomas 1 to 5 mm; 47%, 6 to 10 mm; and 72%, > 11 mm). The sensitivity of FDG-PET also increased with the grade of dysplasia (33%, low grade; 76%, high grade; and 89%, carcinomas). The overall specificity was 84%. CONCLUSION: FDG-PET detects colonic adenomas and the diagnostic test characteristics improve with size and grade of dysplasia of the adenoma.