[Advanced adenoma in 3700 colonoscopies]

OBJECTIVES

To determine the prevalence of colon polyps, distribution in the colon, as well as their histological characteristics, with special mention on advanced adenomas, in an adult population at an endoscopy center in Lima.

MATERIAL AND METHODS

One year long prospective study. We obtained the demographic data, reason for procedure, and endoscopic findings of each colonoscopy. Each polyp was studied separately and its histological findings recorded.

RESULTS

3,701 colonoscopies were done in 3,690 patients; 1,492 (40,4%) had polyps and were included in the study. 997 (27%) had adenomatous polyps and 495 (13.4%) non adenomatous polyps. Adenomatous polyps were found throughout the colon, with a predominance of hyperplasic polyps in the rectum. 78% of the adenomatous polyps and 84% of the advanced adenomas were found in patients older than 50 years old. A total of 260 advanced adenomas were found in 203 patients (5.5%). In the advanced adenomas group, we found 62 lesions (24%) with high grade dysplasia and 12 (4.5%) with early carcinoma; as well as 37 flat lesions (14%) and 26 serrated adenomas (10%). In this group of patients, significant risk factors were: prior history of adenomas or colorectal cancer (46/203 vs. 63/495; p<0.01), and multiple adenomatous polyps found during colonoscopy (67/203 vs. 121/794; p<0.01).

CONCLUSIONS

Adenomatous polyps were the most frequently found polyps in our study; approximately 20% were advanced lesions, especially in patients older than 50 years old.

The natural course of endometrial polyps: could they vanish when left untreated?

OBJECTIVE

To report the occurrence of spontaneous regression of three endometrial polyps detected by hysteroscopy.

DESIGN

Case series.

SETTING

A uterine imaging unit in an academic medical center.

PATIENT(S)

Three patients diagnosed as having an endometrial polyp of 5-8 mm on hysteroscopy.

INTERVENTION(S)

Patient deferral of the surgical procedure for several months.

MAIN OUTCOME MEASURE(S)

Presence of a uterine polyp in the next hysteroscopy.

RESULT(S)

The polyps disappeared spontaneously.

CONCLUSION(S)

Deferral of hysteroscopic polypectomy for a few months in asymptomatic women in the hope of spontaneous regression of the polyps may be justified.

Is barium enema an adequate diagnostic test for the evaluation of patients with positive fecal occult blood?

BACKGROUND

This study aimed to assess the diagnostic accuracy of double contrast barium enema (DCBE) compared to colonoscopy among Hispanic patients with positive fecal occult blood testing (FOBT). Secondary objectives were to determine: the diagnostic accuracy according to adenoma location, size, and pathologic characteristics; and patient satisfaction with each procedure

METHODS

Cross-sectional study comparing the ac curacy of DCBE and colonoscopy in detecting adenomatous polyps and/or colorectal cancer in patients with positive FOBT. DCBE and a colonoscopy were performed in all patients. Polyps identified during colonoscopy were removed and classified by histology. Tolerability and patient's satisfaction with study procedures was assessed.

RESULTS

Fifty patients were enrolled, mainly men with a mean age of 63 years old. Polyps were fou in 40/50 (80%) patients in colonoscopy, compared to 19/50 (38%) in DCBE. Eighty-four percent of polyps were missed by DCBE. Sensitivity of DCBE was 45% and specificity 90% for all adenomas. Diagnostic accuracy of DCBE was 54% for any size adenomas, and 72% for >10 mm adenomas. Sensitivity increased from right to left colon while specificity decreased. Patients preferred colonoscopy over DCBE.

CONCLUSIONS

This study supports the use of colo noscopy as the gold standard test for the evaluation of positive FOBT and was preferred over DCBE b the patients. Diagnostic accuracy of DCBE was inferior to colonoscopy, for all size polyps and larg adenomas. Compared to colonoscopy, DCBE is a substandard test for colorectal cancer screening and may result in ineffective outcomes.

[Correlation of adenomatous polyps and early colorectal cancer. Diagnostic and therapeutic implications]

AIM

To detect the patients with colorectal adenomatous polyps or those with adenocarcinoma areas with a view to prevent and to treat the malignant disease.

MATERIAL AND METHOD

A prospective study including 309 patients hospitalized between 2000-2005 diagnosed with isolated adenomatous polyps after repeated colonoscopies. The research method was selective screening with identification of risk factors regarding the evolution of colorectal polyps in early cancer, using colonoscopy and histopathological examination.

RESULTS

We identified 464 single or multiple isolated polyps of which 399 were adenomas, 59 hyperplastic polyps and 6 other types of lesions. Histologically we recorded 41 (13.27%) polyps with a low grade of dysplasia, 56 (18.12%) with severe dysplasia and 30 (9.7%) intramucosal adenocarcinoma with submucosal invasion.

TREATMENT

Colonoscopic polypectomy was used for benign polyps and in situ carcinoma. In case of adenocarcinoma is probable the invasion of submucosal lymphatics being shown a colorectal resection as appropriate. We performed 279 colonoscopic polypectomies and 30 conventional resections.

CONCLUSIONS

High grade of dysplasia, the number of polyps, ulceration, bleeding, intraepithelial areas of neoplastic transformation are predictive factors for early colorectal cancer. Depth of submucosal invasion of malignant transformed polyps are important pathological factors to predict lymphatic metastasis and to select the therapeutic procedure.

Are many colorectal cancers due to missed adenomas?

BACKGROUND

An unknown number of colorectal cancers could be due to missed adenomas during previous endoscopy. Data in the literature are sparse. A large cross-sectional study was done in a prospective database of all patients diagnosed with colorectal cancer.

METHODS

All consecutive endoscopies over a period of 15 years, in which colorectal cancer was diagnosed were included. All patients who underwent more than one endoscopy and in whom ultimately cancer was diagnosed were studied separately.

RESULTS

Colorectal cancer was diagnosed in 835 patients. Twenty-five patients underwent a previous endoscopy without a cancer diagnosis. These 25 patients were divided into three groups according to the time between the endoscopy in which the cancer was detected and the previous endoscopy. Five out of these 25 patients underwent regular surveillance. Only 11 patients had no argument for regular follow-up. Assuming that these cancers developed from an adenoma than only 11 out of 835 (1.3%) cancers were missed in the adenoma phase. There was no difference in the size of the tumour between the three groups of patients.

CONCLUSION

In normal daily practice, only a small number of clinically important adenomas are missed. The problem of missed adenomas probably is being exaggerated.

Cancer screening in the United States, 2009: a review of current American Cancer Society guidelines and issues in cancer screening

Each year, the American Cancer Society (ACS) publishes a report summarizing its recommendations for early cancer detection, data and trends in cancer screening rates, and select issues related to cancer screening. In 2008, the ACS, the American Gastroenterological Association, the American College of Gastroenterology, the Society for Gastrointestinal Endoscopy, and the American College of Radiology issued a joint update of guidelines for colorectal cancer screening in average-risk adults. In this issue, the current ACS guidelines and recent issues are summarized, updates of testing guidelines for early prostate cancer detection and colorectal cancer screening by the United States Preventive Services Task Force are discussed, and the most recent data from the Centers for Disease Control and Prevention's Behavioral Risk Factor Surveillance System and the National Health Interview Survey pertaining to participation rates in cancer screening are described.

Gastric polypoid intramucosal carcinoma and an adjacently located leiomyoma at the cardia

We report a 65-year-old patient with a gastric polyp of 2.5 cm in diameter located at the cardia on upper gastrointestinal (GI) endoscopy. Pathological examination of the excised polyp showed intramucosal carcinoma. Endoscopic ultrasonography (EUS) reported the lesion as early gastric carcinoma with probable submucosal involvement. On serial sections of the gastrectomy material, the lesion was an intramucosal carcinoma and surprisingly there was a leiomyoma located adjacently.

Gastric polyps: a retrospective analysis of 26,000 digestive endoscopies

BACKGROUND

Gastric polyps are small gastric lesions, asymptomatic in most cases and are generally discovered inadvertently during upper digestive endoscopy.

AIM

To retrospectively review the characteristics and frequency of gastric polyps, derived from the gastric mucosal epithelium in a large series of endoscopies.

METHODS

One hundred and fifty three patients in a series of 26,000 consecutive upper digestive endoscopies done over a 5-year period, being that each patient had only one examination were analyzed and their histological and Yamada classification, as well as their location, size, histopathological findings and treatment studied. All patients had at least one gastric polyp, as confirmed by histological examination.

RESULTS

The polyps were classified as hyperplastic, adenomatous and fundic gland polyps. The most of them measure less than 1 cm (hyperplastic polyps - 60,5%; adenomatous polyps - 73,6%; fundic gland polyps - 72%). Hyperplastic polyps were the most frequent and accounted for 71.3% of the cases, whereas fundic gland polyps accounted for 16.3% and adenomatous polyps for 12.4%. Hyperplastic and adenomatous polyps were primarily single, whereas fundic gland polyps tended to be multiple. A carcinoma was detected in one hyperplastic polyp (0.9%) and in two adenomatous polyps (10.5%). High grade dysplastic foci were found in four adenomatous polyps (21%).

CONCLUSIONS

The digestive endoscopy is the safest and efficient method for the diagnosis of the gastric polyps, that in most of the patients does not show characteristic symptoms. The histopathological definition is not possible to the endoscopic glance being needed the pathologist's aid, once the conduct to be adopted will depend on the result of the biopsy.

Evaluation of a card collection-based faecal immunochemical test in screening for colorectal cancer using a two-tier reflex approach

BACKGROUND

The guaiac faecal occult blood test (gFOBT) has been proved as a screening investigation for colorectal cancer, but has disadvantages. Newer faecal immunochemical tests (FITs) have many advantages, but yield higher positivity rates and are expensive. A two-tier reflex follow-up of gFOBT-positive individuals with a FIT before colonoscopy has been advocated as an efficient and effective approach.

METHODS

A new simple and stable card collection FIT was evaluated.

RESULTS

1124 individuals who were gFOBT positive were asked to provide samples. 558 individuals participated, 320 refused and 246 did not return samples. No evidence of sampling bias was found. 302 individuals tested FIT negative and 256 tested positive. In the 302 FIT-negative individuals, 2 (0.7%) had cancer and 12 (4.0%) had large or multiple (high-risk) adenomatous polyps. In contrast, of 254 positive individuals, 47 (18.5%) had cancer and 54 (21.3%) had high-risk polyps. 93 (30.8%) of the FIT-negative individuals had a normal colonoscopy, but only 34 (13.4%) of the FIT-positive individuals had no pathology. Sensitivity, specificity, and positive and negative likelihood ratios (and 95% CIs) for cancer were 95.9% (84.8 to 99.3), 59.2% (54.7 to 63.5), 2.35 (2.08 to 2.65) and 0.07 (0.02 to 0.27), and for cancer and high-risk polyps were 87.8% (80.1 to 92.9), 65.3% (60.6 to 69.7), 2.53 (2.19 to 2.93) and 0.19 (0.11 to 0.31), respectively.

CONCLUSIONS

A two-tier reflex screening algorithm, in which gFOBT-positive participants are tested with a FIT, is effective in identifying individuals at high risk of significant colorectal neoplasia. This strategy is transferable across different FIT formats. This approach has been adopted for the Scottish Bowel Screening Programme.

MR Colonography with Limited Bowel Preparation: Patient Acceptance Compared with That of Full-Preparation Colonoscopy

PURPOSE

To prospectively evaluate participants' experience and preference of magnetic resonance (MR) colonography with limited bowel preparation compared with full-preparation colonoscopy in participants at increased risk for colorectal cancer.

MATERIALS AND METHODS

This study had institutional review board approval; all participants gave written informed consent. In this multicenter study, consecutive participants undergoing conventional colonoscopy because of a personal or family history of colorectal cancer or adenomatous polyps underwent MR colonography 2 weeks prior to colonoscopy. They all followed a low-fiber diet and were given lactulose and an oral contrast agent (fecal tagging with gadolinium) 2 days before colonography. Before imaging, spasmolytics were administered intravenously, and a water-gadolinium chelate mixture was administered rectally for distention of the colon. Breath-hold T1- and T2-weighted sequences were performed in the prone and supine positions. Participant experience in terms of, for example, pain and burden was determined by using a five-point scale and was evaluated with a Wilcoxon signed rank test; participant preference was determined by using a seven-point scale and was evaluated with the chi2 statistic after dichotomizing.

RESULTS

Two hundred nine participants (77 women, 132 men; mean age, 58 years; range, 23-84 years) were included. One hundred forty-eight participants received sedatives (midazolam) and/or analgesics (fentanyl) during colonoscopy. Participants rated the MR colonography bowel preparation as less burdensome (P<.001) compared with the colonoscopy bowel preparation (10% and 71% of participants rated the respective examinations moderately to extremely burdensome). Participants also experienced less pain at MR colonography (P<.001) and found MR colonography less burdensome (P<.001). Immediately after both examinations, 69% of participants preferred MR colonography, 22% preferred colonoscopy, and 9% were indifferent (P<.001, 69% vs 22%). After 5 weeks, 65% preferred MR colonography and 26% preferred colonoscopy (P<.001).

CONCLUSION

Participants preferred MR colonography without extensive cleansing to colonoscopy immediately after both examinations and 5 weeks later. Experience of the bowel preparation and of the procedure was rated better.

Utility of computed tomographic colonography in surveillance for hereditary nonpolyposis colorectal cancer syndrome

Computed tomographic colonography (CTC) is suggested to be an alternative to colonoscopy as a surveillance tool in subjects with a high risk for colorectal cancer (CRC). To evaluate the utility of CTC we successively examined 78 subjects, all with a DNA mismatch repair gene mutation, by CTC and colonoscopy. We detected altogether 37 polyps or tumors in 28 subjects (prevalence 35.9%), adenomas in 13 subjects (16.7%), CRC in two (2.6%), and hyperplastic polyps in 13 (16.7%). A great majority of the polyps were diminutive. The per-patient sensitivity for detecting all lesions with CTC was 0.25 and 0.29 by two radiologists and the specificities 0.82 and 0.76. For lesions of 10 mm or larger the sensitivities were 0.6 and 1.0 and the specificities 0.96 by each examiner. Each diagnosed the two cancers correctly. We concluded that CTC has an acceptable accuracy for large lesions in the colon but the detection rate for small polyps is not comparable to that in colonoscopy. Therefore CTC remains a second choice in surveillance for use when colonoscopy for some reason is incomplete or unsuitable.

Small, flat colorectal cancers in the UK population: an analysis of resected specimens

OBJECTIVES

To establish the prevalence of small, flat carcinomas in surgically resected colon. To determine whether tumour morphology influences stage at presentation.

METHOD

1763 surgically resected colorectal cancers from one UK centre excised between 1995 and 2004 were examined. Age 69 years, (42-90), M:F equal. Sixty-one tumours < or =20 mm across were identified. Slides were reviewed by a consultant histopathologist and classified using Japanese Research Society Classification, JRSC and TNM staging. Fisher's exact test was used for analysis.

RESULTS

In 61 small cancers, 64% (39/61) showed flat morphology and 33% (20/61) polypoid. Two lesions were unclassifiable. Prevalence was 2.2% of all resected colorectal cancers. More T1 tumours at presentation were polypoid, (30% vs. 8%; P = 0.033). T3 tumours were more likely to be flat than polypoid, (49% vs. 20%; P = 0.016). Infiltration into musclaris mucosa occurred in 77% (30/39) flat tumours. Rates of metastases were high in both groups, (30% polypoid vs. 39% flat, not significant).

CONCLUSIONS

The prevalence of small, flat cancers in resected specimens in the UK concurs with that of Japanese studies. Small, flat cancers should be staged carefully because of high rates of T3/4 disease. The results support the theory of accelerated carcinogenesis in flat cancers.

Detection and treatment of synchronous lesions in colorectal cancer: The clinical implication of perioperative colonoscopy

AIM: To evaluate the clinical significance of pre- and intra-operative colonoscopy for the detection of synchronous lesions in colon cancer.

METHODS: Two hundred and sixty-five pre-operative and 51 intra-operative colonoscopic evaluations were performed in 316 colorectal cancer patients who underwent curative resection from January 2001 to June 2006. The incidence and characteristics of synchronous lesions and their influence on surgery were evaluated.

RESULTS: Two hundred and eighty-two synchronous lesions were detected in 124 (39.2%) of 316 patients including all lesions regardless of their histologic type. True adenomatous polyps were found in 91 (28.8%) of 316 patients, and 17 (5.4% of all patients) patients had synchronous colon cancers. The preoperative identification of synchronous lesions altered the planned surgery in 37 (14.0%) of 265 patients. In 18 patients among the surgically removed cases, the lesions were removed by extending the resection range. Further segmental resection or polypectomy through enterotomy was necessary in 19 patients. Nineteen (37.2%) of 51 intraoperative colonoscopy cases had synchronous lesions. Additional surgical procedures including segmental bowel resection and polypectomy with enterotomy were necessary in 7 (13.7%) of 51 intraoperative colonoscopy cases to remove the lesions.

CONCLUSION: Synchronous colorectal polyps or cancer are frequent and their preoperative detection is important for optimal surgical planning and treatment. Intraoperative colonoscopy is a useful option in cases where a preoperative colonoscopy is not feasible.

Factors associated with the technical performance of colonoscopy: An EPAGE Study

BACKGROUND

Variations in colonoscopy practice exist, which may be related to healthcare quality.

AIMS

To determine factors associated with three performance indicators of colonoscopy: complete colonoscopy, adenomatous polyp diagnosis, and duration.

PATIENTS

Consecutive patients referred for colonoscopy from 21 centres in 11 countries.

METHODS

This prospective observational study used multiple variable regression analyses to identify determinants of the quality indicators.

RESULTS

Six thousand and four patients were included in the study. Patients from private, open-access centres (odds ratio: 3.17, 95% confidence interval: 1.87-5.38) were more likely to have a complete colonoscopy than patients from public, gatekeeper centres. Patients from centres where over 50% of the endoscopists were of senior rank were roughly twice as likely to have an adenoma diagnosed, and longer average withdrawal duration (odds ratio: 1.08, 95% confidence interval: 1.07-1.09) was associated with more frequent adenoma diagnoses. Patients who had difficulty during colonoscopy had longer durations to caecum (time ratio: 2.87, 95% confidence interval: 2.72-3.01) and withdrawal durations (time ratio: 1.26, 95% confidence interval: 1.18-1.33) than patients who had no difficulties.

CONCLUSIONS

Multiple factors have been identified as being associated with key quality indicators. The non-modifiable factors permit the identification of patients who may be at greater risk of not having quality colonoscopy, while changes to the modifiable factors may help improve the quality of colonoscopy.

Utility of MIB-1 (Ki-67) in Evaluating Diminutive Colorectal Polyps With Cautery Artifact

Context.—Accurate interpretation of colorectal polyp histology is essential in the decision-making process during treatment and surveillance following polypectomies. However, interpretation of diminutive colorectal polyps removed by thermal electrocoagulation (hot biopsy technique) is often problematic as a result of cautery artifact.

Objective.—To evaluated the usefulness of the proliferation marker MIB-1 (Ki-67) as an aid in the differential diagnosis of diminutive colorectal polyps with cautery artifact, as adenomatous and nonadenomatous polyps display different patterns of epithelial proliferation.

Design.—Seventy-five diminutive colorectal polyps with extensive cautery artifact displaying at least the upper portions of 3 adjacent crypts with the corresponding surface epithelium were evaluated and immunolabeled with MIB-1. They included 25 cases in which a definitive or presumptive diagnosis could not be reached (indeterminate polyps), 25 cases diagnosed as compatible with adenomatous polyp, and 25 cases diagnosed as compatible with nonadenomatous polyp.

Results.—MIB-1 immunoreactivity was well preserved in the cauterized areas. Among indeterminate polyps, MIB-1 stained upper crypts and surface epithelium in 14 cases (adenomatous polyp staining pattern) and revealed minimal or absent staining in these areas in 11 cases (nonadenomatous polyp staining pattern). All cases diagnosed as compatible with adenomatous polyp displayed the adenomatous polyp staining pattern. In contrast, all cases diagnosed as compatible with nonadenomatous polyp revealed the nonadenomatous polyp staining pattern.

Conclusions.—Immunoreactivity for MIB-1 may be used as a beneficial adjunctive test to help diagnose diminutive colorectal polyps with extensive cautery artifact.

Findings at Follow-up Endoscopies in Subjects With Suspected Colorectal Abnormalities: Effects of Baseline Findings and Time to Follow-up

PURPOSE

Guidelines for colonoscopic surveillance after the removal of colorectal polyps already exist in the United Kingdom and United States. However, there is a continuing need to build up an evidence base on the likely effect of different follow-up policies for specific current findings. This article reports on the colonoscopic surveillance of a cohort of patients in Taiwan. The risk of various outcomes at the second examination is assessed according to findings at the first examination and the interval between examinations.

PATIENTS AND METHODS

Data from baseline and follow-up examinations for 2,287 individuals attending the National Taiwan University Hospital were collected retrospectively. Multivariate logistic regression was used to identify risk factors for the following 4 outcomes: any positive findings; multiple (> or =3) polyps; large (> or =10 mm) polyp(s); or villous adenoma(s) or cancer. The effect of the interval between examinations was assessed in all models.

RESULTS

Older age was an independent risk factor for all outcomes. The number of baseline polyps was a significant risk factor for both positive results and multiple polyps, more severe baseline histology was a risk factor for large polyps and villous adenomas/cancer, and larger baseline polyps were a risk factor for large polyps at follow-up. Interval time was only an independent risk factor for villous adenomas/cancer, which tended to be found at shorter follow-up times. The total number of abnormalities found at follow-up was significantly related to the number of follow-up examinations but not to the total follow-up time.

CONCLUSIONS

Results suggest that, with the possible exception of subjects with villous adenomas at baseline, most reexaminations can safely be delayed for > or =5 years. In the majority of cases staff at the hospital were correctly identifying those subjects at particularly high risk and assigning shorter follow-up intervals accordingly. Models indicate that many of the findings seen at follow-up were due to missed baseline findings.

Relation between plasma enterodiol and enterolactone and dietary intake of lignans in a Dutch endoscopy-based population

Enterolignans are phytoestrogenic compounds derived from the conversion of dietary lignans by the intestinal microflora that may be protective against cardiovascular diseases and cancer. To evaluate the use of enterolignans as biomarkers of dietary lignan intake, we studied the relation between plasma and dietary lignans. We determined the dietary intake of 4 lignans (secoisolariciresinol (SECO), matairesinol (MAT), pinoresinol, and lariciresinol) using the European Prospective Investigation into Cancer and Nutrition FFQ, and plasma enterodiol (END) and enterolactone (ENL) concentrations were determined by liquid chromatography-tandem mass spectrometry. The population consisted of 637 men and women, aged 19-75 y, participating in a case-control study on colorectal adenomas. Participants did not use antibiotics in the preceding calendar year. We found a modest association between lignan intake and plasma END (Spearman r = 0.09, P = 0.03) and ENL (Spearman r = 0.18, P <0.001). The correlation of total lignan intake with plasma enterolignans was slightly stronger than that of only SECO plus MAT. The plasma concentrations of both END and ENL were associated with intake of dietary fiber and vegetable protein but not with intake of other macronutrients. The relation between lignan intake and plasma END was modulated by age and previous use of antibiotics, whereas for ENL, it was modulated by weight, current smoking, and frequency of defecation. However, even when we included these nondietary factors in the regression models, the explained variance in plasma END and ENL remained low (2 and 13%, respectively).

Magnetic resonance imaging in suspected rectal cancer: determining tumor localization, stage, and sphincter-saving resectability at 3-Tesla-sustained high resolution

PURPOSE

To assess image quality and overall accuracy of 3-Tesla (3T)-sustained high-resolution magnetic resonance (MR) imaging for diagnostic preoperative workup in suspected rectal carcinoma.

MATERIAL AND METHODS

Twenty-three patients with suspected rectal cancer underwent unenhanced and contrast-enhanced fat-suppressed pelvic high-resolution MR imaging using a four-channel phased-array pelvic coil at 3T. Image quality, tumor stage, distance from the anorectal margin, and sphincter-saving resectability were prospectively assessed by two blinded readers. The results were correlated with clinical, surgical, and histopathologic findings.

RESULTS

In all 23 patients, MR images were of diagnostic quality, and malignancy was correctly identified in 21 patients. The accuracy for determining sphincter-saving resectability was 100% (19/19). T stage and N stage were correctly diagnosed in 95% and 91%, respectively. MRI allowed correct identification of tumor extension and its relation to surgically relevant pelvic structures including the anorectal margin and mesorectal fascia. Transverse T2-weighted fast spin-echo images compared superiorly to all other sequences for the diagnosis of mesorectal infiltration and lymph node involvement. Moreover, transverse fat-suppressed contrast-enhanced T1-weighted images were valuable for identifying tumor infiltration, while sagittal sections were useful for the detection of longitudinal tumor extension.

CONCLUSION

MR imaging with phased-array receiver coils at 3T facilitated both visualization of different pathologic conditions of the rectum and accurate determination of tumor stage in rectal carcinomas. Thus, this noninvasive diagnostic approach appeared highly suitable for the assessment of patients with suspected rectal carcinoma.

Detection of a K-ras mutation in urine of patients with colorectal cancer

We previously demonstrated that human urine contains small, 150 to 250 nucleotide-sized, soluble DNA derived from the circulation, which may be useful in the detection of colorectal cancer. In this report we have determined the stability of DNA in urine and have found that the half-life time interval of this small, fragmented DNA is at least 4 hours post collection. We further compared, in a blinded study, the frequency of detecting mutated K-ras sequence in DNA isolated from plasma and urine derived from individuals who have either a colorectal carcinoma (CRC), or adenomatous polyps that contain a mutation in codon 12 of the K-ras proto-oncogene. There was an 83% concurrence of mutated DNA detected in urine and its corresponding disease tissue from the same individuals, when paired urine and tissue sections from 20 patients with either CRC or adenomatous polyps were analyzed for K-ras mutation. However, only a 56% concurrence was observed when the matched plasma specimens were tested from these 20 patients. These results suggest that urine might be a better resource for detecting K-ras mutation in circulating DNA.