放大肠镜在结直肠肿瘤样病变诊断治疗中的应用价值

目的 探讨应用放大肠镜诊断结直肠肿瘤样病变及指导治疗的价值。方法 用放大肠镜对61例结直肠肿瘤患者的78个病灶进行了染色后的放大观察，按工藤分型进行了腺管开口类型诊断；同步进行镜下摘除或手术切除后，将放大肠镜诊断结果与组织病理诊断结果相比较，分析其一致性。结果（1）依据放大肠镜所见，诊断腺瘤等肿瘤性病变，总体符合率为96.2％，敏感性98.4％，特异性85.7％；（2）依据放大肠镜的诊断，对70个（89.7％）良性病变进行了同步微创治疗；（3）结合放大观察的肠镜检查，为决定其他8个病灶的治疗方案提供了重要依据。结论 放大电子肠镜诊断结直肠肿瘤样病变及时、准确，利用它可以同步完成病变的微创治疗。     

Timing and detection of metachronous colorectal cancer

Background: Surveillance following surgery for colorectal cancer aims to detect treatable disease relapse or metachronous neoplasia. Metachronous cancers have been reported within a short duration of follow‐up, and may be due to missed lesions, seeding into polypectomy wounds or accelerated tumorigenesis related to genetic instability. The purpose of this study was to establish the timing and method of detection of metachronous cancers in a large population of patients in a surveillance database. Methods: This retrospective clinical study used patients with an elevated risk of colorectal neoplasia included in a colonoscopy‐based surveillance programme to identify those with two or more colorectal cancers, as well as the timing and method of detection of the tumours. Colonoscopy reports and histopathology results were reviewed to determine quality of bowel preparation, tumour location, and polypectomy data. Results: Fourteen (2.5%) of 569 patients with colorectal cancer developed metachronous malignant tumours, nearly half of which were identified within 3 years of follow‐up by surveillance colonoscopy or an interval faecal immunochemical test for globin. None of these had a previous polypectomy at the site of the second tumour, bowel preparation at the original colonoscopy was good in most cases, and no metachronous tumour occurred at a colonic flexure. Conclusion: Metachronous cancers can occur early during follow‐up after curative intent resection, and early colonoscopic surveillance may be warranted.     

The true incidence of synchronous cancer of the large bowel: A prospective study

The reported incidence of synchronous primary cancers and polyps associated with single cancers of the large bowel is varied. In a prospective study over a 5 year period, 166 patients with primary colorectal cancer had either total colonoscopy preoperatively or total colonoscopy within 6 months of surgical resection. One hundred seventy-eight cancers were detected. Synchronous cancers were found in eight patients (5 percent), and benign neoplastic polyps were demonstrated in 46 patients with single cancers (28 percent) and in 112 patients with synchronous primary cancers (38 percent). Of significance is that seven of eight (88 percent) synchronous cancers would not have been included in the standard resection for the index primary cancer. Similarly 31 of 46 neoplastic polyps (67 percent) were not in the same surgical segment as the primary cancer. Total large bowel evaluation, preferably using colonoscopy, is essential in all patients with cancer of the large bowel.     

The impact of an incomplete preoperative colonoscopy in patients with colorectal cancer

Total large bowel evaluation remains an essential step in the treatment of patients with colorectal cancer (CRC). Colonoscopy is the gold standard in the evaluation of the colon for colorectal tumors, but may be incomplete due to tumor obstruction, which is a frequent event in distal cancers. Double-contrast barium enema has a lower accuracy and is not ideal in the presence of signs of obstruction. In theory, intraoperative colonoscopy is a valid alternative, but its routine use is impeded by various practical limitations. Preoperative survey of the colon in 521 consecutive patients treated for CRC in our department was based on colonoscopy (92.5%). Our series was characterised by a high percentage of distal lesions (76.4%) and therefore by a high percentage of incomplete preoperative colonoscopies (50.4%) due to tumor obstruction. In the presence of an incomplete preoperative colonoscopy, we evaluated the entire colon with a double-contrast barium enema in selected cases (36.7%) and with a postoperative colonoscopy within 3 months of surgery in almost all patients (93.4%). The overall rate of complete endoscopic evaluation, either pre- or postoperatively, was 96.7%. The incidence of adenomas was significantly higher in the preoperative examinations as compared to early postoperative colonoscopy. This means that in distal cancer the vast majority of polyps will be located in the distal colon and therefore included in a standard resection. Four patients (0.8%), required a second operation for treatment of a missed lesion (2 benign and 2 malignant). The need for a repeat surgery apparently did not affect the therapeutic results in these four patients. On the basis of our experience, intraoperative colonoscopy would not appear to be a mandatory procedure in all cases of incomplete preoperative evaluation of the colon. However, in the absence of prospective, randomised trials comparing intraoperative vs early postoperative colonoscopy, the dilemma as to the strategy of choice remains.     

Pre-operative or postoperative colonic examination for synchronous lesions in colorectal cancer

A review of 130 consecutive large bowel examinations at which a cancer of the colon or rectum was diagnosed has been undertaken. Of 50 patients examined by colonoscopy, the whole colon was seen in only 21 (42 per cent) and almost half of these had a tumour in the caecum or ascending colon. In most cases, an incomplete examination was the result of narrowing of the lumen by the tumour preventing passage of the endoscope. Of 80 patients examined by double contrast barium enema, the entire length of the colon was visualized in 83 per cent but the quality of the examination was sufficient to confidently exclude synchronous neoplastic lesions in only 51 per cent. The incidence of synchronous cancer in this series was within the expected range, although two such cancers were not detected until laparotomy, but the incidence of synchronous adenomas was two-thirds of the expected number in colonoscopy patients and one-third in those examined by barium enema. It is concluded that, in patients with known colorectal cancer, preoperative investigation is unreliable for the detection of all synchronous neoplasia and that patients should have postoperative colonoscopy.     

Conventional colonoscopy versus chromoendoscopy and magnifying endoscopy for the diagnosis of colorectal lesions: a comparative prospective study in 995 patients

Early endoscopic diagnosis of colorectal cancers is the best tool for the reduction of colorectal cancer mortality, but conventional colonoscopy seems unable to detect minor changes in the colorectal mucosa. The authors compare the results of conventional colonoscopy and chromoendoscopy plus magnifying endoscopy for the detection of colorectal lesions. This prospective study evaluated 995 consecutive selected patients. All patients with a previous diagnosis of colorectal polyps, inflammatory bowel disease, history of colorectal surgery, high coagulative risk or poor bowel preparation were excluded from the study. All examinations were performed by a single endoscopist. The authors compared the results of conventional endoscopy and chromoendoscopy with a 0.4% indigo carmine solution and magnifying endoscopy. At the end of each examination, data from ordinary and dye-spraying views were carefully recorded. A total of 202 protruding, 99 flat and 5 depressed lesions were detected. The incidence of high-grade dysplasia and early carcinoma was 9.9% for protruding lesions, 13.1% for flat lesions and 60% for depressed lesions. Chromoendoscopy revealed new neoplastic patterns not detectable at conventional endoscopy in 127 patients. This prospective study shows the high accuracy rate of chromoendoscopy for the detection of non-polypoid lesions. Chromoendoscopy could be used as a routine procedure in order to enhance the early diagnosis of colorectal cancers.     

Virtual colonoscopy in stenosing colorectal cancer

In 5-10% of patients it is not possible to achieve a complete endoscopic examination of the colon, because of obstructing cancer, excessive length of the colon, anatomical abnormalities or adhesions. Virtual colonoscopy is currently capable of investigating the colic lumen with a non-invasive technique, with high specificity and sensitivity. From January 2005 to July 2007 we treated 21 patients with obstructing neoplastic colorectal lesions, preventing a complete endoscopic examination. In all patients we performed a virtual colonoscopy, which revealed the presence of synchronous lesions (19%): a pedunculated polyp in two cases, a sessile polyp in one case and a right colonic vegetating lesion. In the 21 patients studied we performed a follow-up colonoscopy 3 months after the surgical treatment. No other endoluminal lesions were found, confirming the results of virtual colonoscopy. In our experience virtual colonoscopy presented 100% sensitivity and specificity. In this selected group of patients with obstructing lesions of the colon, virtual colonoscopy enables the surgeon to evaluate the entire colon, avoiding the execution of an intraoperative colonoscopy and possible surgical reintervention due to the finding of synchronous neoplastic lesions at postoperative follow-up endoscopy.     

From advanced diagnosis to advanced resection in early neoplastic colorectal lesions: Never-ending and trending topics in the 2020s

Colonoscopy represents the most widespread and effective tool for the prevention and treatment of early stage preneoplastic and neoplastic lesions in the panorama of cancer screening. In the world there are different approaches to the topic of colorectal cancer prevention and screening: different starting ages (45-50 years); different initial screening tools such as fecal occult blood with immunohistochemical or immune-enzymatic tests; recto-sigmoidoscopy; and colonoscopy. The key aspects of this scenario are composed of a proper bowel preparation that ensures a valid diagnostic examination, experienced endoscopist in detection of preneoplastic and early neoplastic lesions and open-minded to upcoming artificial intelligence-aided examination, knowledge in the field of resection of these lesions (from cold-snaring, through endoscopic mucosal resection and endoscopic submucosal dissection, up to advanced tools), and management of complications.     

Detection of colorectal lesions with virtual computed tomographic colonography

BACKGROUND: The aim of our study was to compare the performance of virtual computed tomographic colonography with that of conventional colonoscopy in a blinded, prospective study in 165 patients with suspected colorectal lesions. METHODS: There were 165 patients, all referred for conventional colonoscopy, who underwent preliminary virtual computed tomographic colonography. Computed tomograhic images of all suspected lesions were analyzed and subsequently compared with conventional colonoscopy findings. RESULTS: There were 30 colorectal cancers and 37 polyps identified at conventional colonoscopy. Virtual computed tomographic colonography correctly detected all cancers, as well as 11 of 12 polyps of 10 mm in diameter or larger (sensitivity, 92%); 14 of 17 polyps between 6 and 9 mm (sensitivity, 82%); and 4 of 8 polyps of 5 mm or smaller (sensitivity, 50%). The per-patient sensitivity and specificity were 92% and 97%, respectively. CONCLUSIONS: Virtual computed tomographic colonography has a diagnostic sensitivity similar to that of conventional colonoscopy for the detection of colorectal lesions larger than 6 mm in diameter.     

Colonoscopic surveillance after curative colorectal resection: Results of an empirical surveillance programme

Introduction Colonoscopic surveillance after colorectal cancer resection is widely practised despite little evidence that it improves survival. The optimum protocol for colonoscopic follow‐up after colorectal cancer resection has not yet been elucidated. We audited the outcome of an empirical colonoscopic follow‐up programme in a cohort of patients who underwent colorectal resection with a minimum of five years follow‐up to establish patterns of metachronous neoplasia and suitable surveillance intervals. Methods The colonoscopic records, biopsy results and follow‐up details of patients diagnosed with colorectal cancer between June1990 and June1996 were reviewed. The number and type of metachronous neoplastic lesions diagnosed was recorded. Rates of development of new neoplasms were estimated by calculating the time from operation to their first discovery. Factors predictive of further development of polyps or cancer were sought. Results were compared to published reports of intensive follow‐up programmes. Results Seven hundred and ninety‐eight patients underwent colorectal resection with curative intent during the study period. 226 patients had one or more follow‐up colonoscopies (mean time post resection 48.8 months). In total 352 colonoscopies, encompassing 1437 patient years of surveillance, were performed. Nine metachronous cancers in eight patients, five of which were asymptomatic were diagnosed by colonoscopy at a mean of 63 months. Three asymptomatic recurrences were diagnosed but all were inoperable. 70 (31%) patients had adenomatous polyps diagnosed after a mean time from operation of 34 months for simple adenomatous polyps and 21 months for those with advanced features. Patients with multiple polyps or advanced polyps at the initial colonoscopy were more likely to form subsequent polyps. Only 5.8% of patients with a single adenoma or a normal colon formed an advanced adenoma over the next 36 months of surveillance. Conclusion The results of an empirical colonoscopic follow‐up programme compared favourably to the results of the intensive programmes reported in the literature. Most patients are at very low risk of developing significant colonic pathology over the first five years after resection. Colonoscopic surveillance intervals need not be less than five years unless the patient has multiple adenomas or advanced adenomas at the first colonoscopy. Three yearly surveillance intervals are most probably adequate in these individuals.     

Virtual colonoscopy vs conventional colonoscopy in patients at high risk of colorectal cancer – a prospective trial of 150 patients

Objective Virtual colonoscopy (VC)/CT colonography has advantages over the well‐documented limitations of colonoscopy/barium enema. This prospective blinded investigative comparison trial aimed to evaluate the ability of VC to assess the large bowel, compared to conventional colonoscopy (CC), in patients at high risk of colorectal cancer (CRC). Method We studied 150 patients (73 males, mean age 60.9 years) at high risk of CRC. Following bowel preparation, VC was undertaken using colonic insufflation and 2D‐spiral CT acquisition. Two radiologists reported the images and a consensual agreement reached. Direct comparison was made with CC (performed later the same day). Interobserver agreement was calculated using the Kappa method. Postal questionnaires sought patient preference. Results Virtual colonoscopy visualized the caecum in all cases. Five (3.33%) VCs were classified as inadequate owing to poor distension/faecal residue. CC completion rate was 86%. Ultimately, 44 patients had normal findings, 44 had diverticular disease, 11 had inflammatory bowel disease, 18 had cancers, and 33 patients had 42 polyps. VC identified 19 cancers – a sensitivity and specificity of 100% and 99.2% respectively. For detecting polyps > 10 mm, VC had a sensitivity and specificity (per patient) of 91% and 99.2% respectively. VC identified four polyps proximal to stenosing carcinomas and extracolonic malignancies in nine patients (6%). No procedural complications occurred with either investigation. A Kappa score achieved for interobserver agreement was 0.777. Conclusion Virtual colonoscopy is an effective and safe method for evaluating the bowel and was the investigation of choice amongst patients surveyed. VC provided information additional to CC on both proximal and extracolonic pathology. VC may become the diagnostic procedure of choice for symptomatic patients at high risk of CRC, with CC being reserved for therapeutic intervention, or where a tissue diagnosis is required.     

Sensitivity of double contrast barium enema and colonoscopy for the detection of colorectal neoplasms

Background: Double contrast barium enema (DCBE) is the examination carried out most frequently for investigation of patients with large bowel symptoms. The aim of this study was to compare the sensitivity of DCBE and colonoscopy for the detection of colorectal cancer and neoplastic polyps ?1 cm. Methods: All patients undergoing DCBE (1389) or colonoscopy (1081) as the primary investigation for large bowel symptoms or for cancer or polyp surveillance in the first 9 months of 1997 at a large teaching hospital were included in this study. At 1 and 2 years following investigation, a computerized search of appropriate diagnosis and procedure codes to detect any missed cancers or polyps was performed for all patients with a normal investigation. Results: Almost 19% of patients in both groups went on to have an additional large bowel investigation over the 2-year period. In the DCBE group, 47 patients (3.5%) had a cancer diagnosed; eight of them had been missed at the primary investigation (sensitivity 83%). In the colonoscopy group, 37 patients (3.4%) had a cancer; one of them had been missed at the primary investigation (sensitivity 97.5%). Neoplastic polyps ?1 cm were diagnosed in 1.6% of the DCBE group and in 7.7% of the colonoscopy group, with sensitivities of 21.7% and 91.4%, respectively. Nine patients (0.6%) had a false positive diagnosis of cancer in the DCBE group; one had an iatrogenic bowel perforation following flexible sigmoidoscopy. Conclusions: Where adequate facilities and expertise exist, colonoscopy should be the investigation of choice for most patients with large bowel symptoms suggestive of neoplastic disease. apd: 14 May 2001     

The prevalence of small, flat colorectal cancers in a western population

Objective Small, flat colorectal cancers have been widely reported in the Japanese literature but are thought to occur rarely outside Japan. The aim of this retrospective cohort study was to clarify the prevalence of flat colorectal cancer in a Western population. Methods One thousand and twenty‐six consecutive colonoscopies performed by a single experienced endoscopist were retrospectively analysed over a two‐year period. The morphology, site and histological appearance of all documented colorectal cancers (CRC) were recorded. Results Forty‐seven cases of CRC were detected, five of which (10%) demonstrated flat configuration. Flat cancers varied between 8 and 15 mm in diameter (mean 11 mm). Histologically, all flat lesions were moderately differentiated Dukes A adenocarcinomas. Two of these cancers contained no adenomatous component. Conclusion This study confirms that small, flat colorectal cancers are not an uncommon finding at colonoscopy in Western patients. Compared to polypoid neoplastic lesions, flat cancers appear to undergo malignant change at a smaller size.     

Clinical significance of incidental focal colorectal 18F‐fluorodeoxyglucose uptake: our experience and a review of the literature

Aim The aims of the present study were: (i) to evaluate the focal incidental colorectal uptake of ¹⁸F‐fluorodeoxyglucose ([¹⁸F]FDG) and to correlate it with colonoscopy and histological findings; (ii) to evaluate the relationship between the presence/absence of neoplastic disease and clinical data and the anatomical site of [¹⁸F]FDG uptake; and (iii) to compare our results with those reported for incidental colorectal uptake of [¹⁸F]FDG in the literature and those obtained from various screening programmes for colorectal cancer. Method The database of 6000 patients referred for [¹⁸F]FDG positron emission tomography/computed tomography (PET‐CT) to our centre was retrospectively reviewed for incidental colorectal uptake of [¹⁸F]FDG. Patients with focal uptake were selected and the aetiology of PET findings was verified with a subsequent colonoscopy and histopathological analysis when available. Results Incidental colorectal uptake of [¹⁸F]FDG was seen in 144 (2.4%) patients, of whom 64 (1.1%) had focal uptake; 48 out of these 64 patients underwent colonoscopy, which showed malignant tumours in 12 (25%), premalignant lesions in 19 (40%), non‐neoplastic lesions in six (12%) and lesions not confirmed by colonoscopy in 11 (23%). Our data agreed with previously published data. Statistical analysis did not show any significant relationship between the presence/absence of neoplastic disease and patient sex or age, type of primary disease and anatomical site of [¹⁸F]FDG uptake. Comparing our data with various screening programmes, a significant difference was found only with series in which colonoscopy was performed in patients at high risk for colorectal cancer. Conclusion Focal incidental colorectal uptake of [¹⁸F]FDG is observed in about 1% of PET/CT studies and carries a high risk of neoplastic disease. A PET‐CT report should suggest colonoscopy when abnormal findings are reported.     

Frequency of early colorectal cancer in patients undergoing colonoscopy.

BACKGROUND: Early colorectal cancer is defined as carcinoma limited to the mucosa or submucosa. Up to 20 per cent of all colorectal cancers treated in some Japanese institutions are early cancers. These cancers are sometimes flat or depressed, and may be less than 1 cm in diameter. The aim of this study was to identify the frequency and morphology of early colonic cancers detected at colonoscopy by a surgeon aware of and looking for such lesions. METHODS: A review was made of all colonoscopies performed by or under the supervision of a single endoscopist between 1990 and 1998. Follow-up and outcome of all patients with early colorectal cancer was undertaken. RESULTS: Ninety-five invasive colorectal cancers were identified from 2198 colonoscopies. Eighteen were early colorectal cancers (T1). Macroscopically these were flat (nine tumours), villous (four) and pedunculated (five). Two patients had lymph node metastasis. The median size of flat cancers was 20 (range 9-30) mm. Median follow-up was 3 years. One patient had local recurrence, and another, whose early cancer was metachronous, died from metastatic cancer. CONCLUSION: This study identified early colonic cancer with similar frequency and morphology to that reported by the Japanese. Colonoscopy should be considered as the investigation of choice for patients with large bowel symptoms.     

A novel indicator for surveillance colonoscopy following colorectal cancer resection

Introduction Current surveillance for recurrent intraluminal or metachronous colorectal cancer following resection is largely undertaken by colonoscopic examination of the remaining colon. The burden on colonoscopic services is high and the procedure is expensive. Immunological faecal occult blood testing (FOBT) is a sensitive and specific test for detecting colorectal cancer, and may fine tune the need for timely surveillance colonoscopy. Methods Consecutive patients due for surveillance colonoscopy following colonic resection for cancer were prospectively studied. Each patient had a single faecal sample obtained at per rectal examination on a gloved examining finger. This was subjected to immunological FOBT in the clinic, and patients were categorized as FOBT positive or negative, according to the result. Colonoscopy as well as ultrasound or CT of the liver were performed within eight weeks of FOBT. Results Six hundred and eleven patients had both FOBT and colonoscopy. Fifty‐nine (13.6%) were categorized as FOBT‐positive. Of these, nine had biopsy‐proven recurrent or metachronous cancer, 12 patients had one, or more adenomatous polyps, one patient had radiation proctitis and two patients had pan‐colonic mucositis following chemotherapy. In the remaining 552 FOBT‐negative patients, no cancers were found. Thirty‐eight patients had polyps that were removed. The sensitivity and specificity for detecting cancer by immunological FOBT was 100% sensitivity for detecting adenomatous polyps was 24% but specificity was 93%. Conclusion The immunological faecal occult blood test provides sensitive detection of metachronous and recurrent cancer in postoperative surveillance. Routine application may be used to reduce the frequency of colonoscopic surveillance, as a negative FOBT may be taken as a sign that colonoscopy may be deferred safely.     

Multiple colorectal carcinomas and colorectal carcinoma associated with extracolonic malignancies

In this study, we analyzed 149 surgical cases of colorectal cancer between January 1983 and August 1989. Thirteen cases (8.7 per cent) of colorectal primary cancer associated with extracolonic primary malignancy of 14 lesions and 10 cases (6.7 per cent) of multiple primary colorectal cancers were included. Among the 14 lesions of extracolonic primary malignancy, there were 6 gastric carcinomas, 2 endometrial carcinomas, 2 urinary bladder carcinomas, and one each in the esophagus, liver, bile duct and jejunum. The second tumor was not detected preoperatively in 3 of 4 cases of synchronous multiple primary colorectal carcinoma. A curative resection was done in 10 (77 per cent) out of 13 cases of colorectal cancer associated with extracolonic malignancy, while 7 (88 per cent) out of 8 cases of multiple colorectal cancers had a curative resection. Nine patients (69 per cent) with colorectal cancer associated with extracolonic malignancy were disease-free for 2 months to 14 years. Seven patients (88 per cent) with multiple colorectal cancers were disease-free for one to 22 years. We recommend, therefore, that in any patient with colorectal cancer, the entire large bowel should be thoroughly searched for any other primary tumors, by taking the existence of extracolonic tumors into account. A curative resection should be performed, and the follow-up period should be life-long.This paper was presented at the 33rd World Congress of Surgery, Toronto, Canada, 1989.     

Colonoscopy after curative resection of colorectal cancer

Colonoscopy is generally considered to be an important part of the follow-up program for patients who have undergone curative resection of colorectal cancer. However, there are few data available concerning the frequency with which colonoscopy should be performed and for what length of time after operation. Since 1978, our policy has been to examine the colon annually in these patients using colonoscopy alternating with barium enema. We have evaluated the results in 100 patients over a four-year period. Based on size and histology, the significant colonoscopic findings were new colon cancers in three patients and 11 polyps demonstrating increased risk for malignancy in nine patients. This represents an interval yield of 3% per year. From these results and other reports, we recommend that these patients undergo total colonoscopy in the perioperative period to identify and remove synchronous lesions of the colon, and that examination of the remaining colon should be performed annually, preferably with colonoscopy, for at least the first four years after curative resection.     

Computed tomography findings of bowel wall thickening: its significance and relationship to endoscopic abnormalities

INTRODUCTION

The aim of this study was to conduct retrospective analysis of abdominopelvic computed tomography (CT) reports, identifying those patients in whom bowel wall thickening (BWT) was observed, and to correlate these reports with subsequent endoscopic evaluation.

METHODS

Formal reports for all patients undergoing abdominopelvic CT between February 2007 and September 2009 were reviewed. Where patients were identified as having colorectal ‘wall thickening’, results of subsequent endoscopic evaluations were documented. Only those patients with a report of BWT who had follow-up endoscopy (colonoscopy, sigmoidoscopy) were included in the analysis.

RESULTS

A total of 165 patients were included. Abnormalities on endoscopy at the exact site of the BWT on CT were found in 95 patients (57.58%); in 36 cases (21.82%) this was a malignant lesion. BWT of the transverse colon was significantly more likely to correspond to an endoscopic finding of cancer than other sites (p=0.034). Rectal bleeding was reported significantly more often in patients with BWT and neoplastic disease on endoscopy compared with those with normal endoscopy (p=0.04). Excluding patients with inflammatory/diverticular lesions, 59.02% of Caucasians had a neoplastic lesion at the site of reported BWT, significantly higher than the other ethnic groups (p=0.008). There were 38 patients (23.03%) who did not present with bowel symptoms and, of these, 6 were diagnosed subsequently with colorectal cancer.

CONCLUSIONS

This study supports endoscopic evaluation to investigate patients with CT evidence of BWT, especially in cases involving the transverse colon, in Caucasian patients or in association with symptoms of rectal bleeding.     

Detection of incidental colorectal tumours with 18F‐labelled 2‐fluoro‐2‐deoxyglucose positron emission tomography/computed tomography scans: results of a prospective study

Aim This study assessed the clinical significance of incidental colorectal 2‐fluoro‐2‐deoxyglucose (FDG) uptake using ¹⁸F‐FDG positron emission tomography/computed tomography (PET/CT) scans and evaluated the importance of colonoscopy when incidental colorectal FDG uptake was observed. Method A prospective study was designed and conducted at a single institution over a 2‐year period. In patients undergoing PET/CT scans, all with FDG uptake in the colorectum were assigned to have colonoscopy and biopsy. The value of PET/CT scanning was studied by comparison with the colonoscopy and biopsy results. Results Among 10 978 PET/CT scans, one or more focal uptakes of FDG in the colorectum were observed in 148 (1.35%) patients. In 136 valid patients, malignant colorectal tumours and polyps were found in 23.5% and 20.5%, respectively,, while the colon in the other 56% was normal. A higher false‐positive rate was found in the right colon compared with the distal colorectum (66.2%vs 36.7%, P = 0.004). A significant increase of the maximum standardized uptake (SUVmax) value was found among normal, polyps and cancer groups. Multivariate analysis revealed that SUVmax was the risk factor for predicting colorectal cancer or polyps and FDG uptake in the right colon was a negative predictive factor for finding cancers or polyps. Conclusions Our study proves the necessity of colonoscopy when incidental FDG uptake is found on PET/CT imaging. The false‐positive FDG uptake is more commonly observed in the right colon. Although the SUVmax value is higher in cancer patients, a high SUVmax value does not necessarily result in malignancies.