Negative Screening Colonoscopy Research Articles

Cancer Screening Unnecessary for Many Older Adults

A substantial proportion of older adults in the United States undergo unnecessary and even harmful screening for colon, prostate, breast, and cervical cancer, contrary to clear, well publicized guidelines, according to two separate studies published in JAMA Internal Medicine. In the case of colon cancer, most of these unnecessary screenings can be attributed to patients getting rescreened more frequently than at the 10-year intervals recommended, while continued screening past the age of 75 years is also a culprit. With the other cancers, the main reason for these unnecessary procedures is continuing screening in patients who have a short life expectancy because of advanced age or irreversible health problems. In both reports, the investigators emphasized that unnecessary cancer screening is not only inefficient and expensive from a societal perspective but is also harmful for individual patients because it exposes them to invasive procedures and complications, impairs their quality of life, and sometimes leads to downstream overdiagnosis and overtreatment of cancers that would have remained asymptomatic until the patient died of other causes. In one of the studies, researchers analyzed data from the population-based National Health Interview Survey, which assesses approximately 90,000 Americans each year to provide health information representative of the U.S. population. They focused on 27,404 participants aged 65 years and older who reported on the cancer screening they underwent between 2000 and 2010. A validated mortality index was used to calculate each respondent's 9-year mortality risk based on several factors, said Trevor J. Royce, MD, of the departments of radiation oncology and medicine, University of North Carolina at Chapel Hill, and his associates. They found that contrary to numerous recommendations, “a sizable proportion of the U.S. population who have less than a 9-year life expectancy” underwent screening for cancer, including 55% of men who were screened for prostate cancer, 41% of people screened for colorectal cancer, 38% of women screened for breast cancer, and 31% of women screened for cervical cancer. Most egregiously, as many as 56% of women who had undergone hysterectomy for benign reasons were still undergoing annual Pap tests to detect cervical cancer, even though most of them no longer had a cervix. And overscreening for prostate cancer was especially common, “possibly because [prostate-specific antigen] testing is viewed as a simple, safe blood test, with little recognition of the important downstream harms,” Dr. Royce and his associates said (JAMA Intern Med 2014;174:1558-65). In the other study, researchers used microsimulation modeling to assess whether screening more intensively than recommended for colorectal cancer would be favorable for individual patients or for society as a whole. They created two hypothetical cohorts of 10 million Medicare beneficiaries at average risk for the disease: the first included patients who had a negative screening colonoscopy at age 55 years and the second included patients who had never been screened for colorectal cancer, said Frank van Hees, MSc, a researcher in the department of public health, Erasmus University Medical Center, Rotterdam, the Netherlands, and his associates. The model simulated recommended screening (that is, colonoscopy at ages 65 and 75 years), as well as several shorter screening intervals, screening up to age 85 years, and screening up to age 95 years. It factored into the analyses the sensitivity rates for colonoscopy for adenomas or carcinomas at various stages, age-specific risks for gastrointestinal and cardiovascular complications requiring hospitalization, and survival rates after a variety of possible clinical diagnoses. The balance among benefits, burden, and harm was unfavorable in almost every scenario tested, outside the recommended screening scenario. For example, “when a screening interval of 5 instead of 10 years was applied, the gain in quality of life by preventing additional life-years with colorectal cancer care was exceeded by the loss of quality of life due to additional colonoscopies and additional complications.” Similarly, when colonoscopy was continued to age 85 years instead of ceasing at age 75 years, “the overall loss of quality of life exceeded the associated increase in life-years gained.” Harms were even greater when colonoscopy was continued to age 95 years or when the screening interval was reduced to 3 years, Mr. van Hees and his associates said (JAMA Intern Med 2014;174:1568-1576). Rather than emphasizing the wastefulness of nonrecommended colorectal screening, stressing that such screening negatively affects patient health is more likely to get both physicians and patients to abandon it. “One simple screen” often forces elderly or frail patients with many comorbidities onto a track of continued surveillance, biopsies, and removal of lesions that are unlikely to cause harm, with the attendant complications, the investigators added.

Incidence of colorectal adenomas: birth cohort analysis among 4.3 million participants of screening colonoscopy.

Most colorectal cancers develop from adenomas. We aimed to estimate sex- and age-specific incidence rates of colorectal adenomas and to assess their potential implications for colorectal cancer screening strategies. Sex- and age-specific incidence rates of colorectal adenomas were derived by a birth cohort analysis using data from 4,322,085 screening colonoscopies conducted in Germany and recorded in a national database in 2003-2012. In addition, cumulative risks of colorectal cancer among colonoscopically neoplasm-free men and women were estimated by combining adenoma incidence rates with previously derived adenoma-colorectal cancer transition rates. Estimated annual incidence in percentage (95% confidence interval) in age groups 55-59, 60-64, 65-69, 70-74, and 75-79 was 2.4 (2.2-2.6), 2.3 (2.1-2.6), 2.4 (2.1-2.6), 2.2 (1.8-2.5), and 1.8 (1.2-2.3) among men, and 1.4 (1.3-1.5), 1.5 (1.4-1.7), 1.6 (1.4-1.8), 1.6 (1.3-1.8), and 1.2 (0.8-1.6) among women. Estimated 10- and 15-year risks of clinically manifest colorectal cancer were 0.1% and 0.5% or lower, respectively, in all groups assessed. Annual incidence rates of colorectal adenomas are below 2.5% and 2% among men and women, respectively, and show little variation by age. Risk of clinically manifest colorectal cancer is expected to be very small within 10 years and beyond after negative colonoscopy for men and women at all ages. The use of rescreening after a negative screening colonoscopy above 60 years of age may be very limited.

Minimal benefit of earlier-than-recommended repeat colonoscopy among US Medicare enrollees following a negative colonoscopy.

A large proportion of US Medicare beneficiaries undergo earlier-than-recommended follow-up colonoscopies after negative screening colonoscopy. Such practice entails substantial cost and added risk. To compare the risk of colorectal cancer (CRC) associated with varying follow-up colonoscopy intervals following a negative colonoscopy, and to determine whether the potential benefit of a shorter colonoscopy follow-up interval would differ by gender. We conducted a weighted cohort study using the Surveillance, Epidemiology and End Results-Medicare linked database (1991-2006) among 932,370 Medicare enrollees who are representative of the entire US elderly population. We compared the cumulative incidence of CRC among patients who underwent follow-up colonoscopies at different intervals following a negative colonoscopy. The primary outcome was incident CRC. The eligible study cohort (n = 480,864) included 106,924 patients who underwent ≥1 colonoscopy. Men were more likely to require polypectomy during their initial colonoscopy than women. Compared to the recommended 9-10 year follow-up colonoscopy interval, an interval of 5-6 years was associated with the largest CRC cumulative risk reduction [i.e. 0.17% (95% CI: 0.009-0.32%)]. The magnitude of risk reduction associated with shorter colonoscopy follow-up intervals was not significantly different between men and women. Among elderly individuals who undergo a negative colonoscopy, the magnitude of reduction in the cumulative CRC risk afforded by earlier-than-recommended follow-up colonoscopy is quite small, and probably cannot justify the risk and cost of increased colonoscopy frequency. In addition, there are insufficient differences between men and women to warrant gender-specific recommendations.

Screening colonoscopy versus sigmoidoscopy: implications of a negative examination for cancer prevention and racial disparities in average-risk patients

Both colonoscopy and flexible sigmoidoscopy are accepted procedures for colorectal cancer (CRC) screening in the United States. To compare risk of CRC after negative findings on screening colonoscopy versus sigmoidoscopy and to evaluate racial/ethnic disparities in postscreening CRC. Retrospective, comparative cohort study. Integrated community-based health-care system. Average-risk patients 50 to 75 years of age with negative findings on an initial endoscopic screening examination from January 2000 to December 2010. Colonoscopy versus sigmoidoscopy as the initial screening procedure. Incident cases of CRC identified via a prospective internal cancer registry, risk of CRC determined by Cox regression adjusted for age, sex, race/ethnicity, and comorbidity. The study cohort included 138,297 patients (42,938 patients with negative findings on colonoscopy and 95,359 with negative findings on sigmoidoscopy). The median age was 57.9 years (interquartile range 53.0-64.1 years). Women comprised 51.8% of the cohort with 42.2% non-Hispanic white patients, 24.1% Hispanic patients, 10.7% non-Hispanic black patients, 9.7% Asian patients, and 13.3% other/unknown. A total of 241 cases of CRC was detected during 553,543 person-years of follow-up. The adjusted hazard ratio (HR) of postscreening CRC was 0.42 (95% confidence interval [CI], 0.28-0.64; P < .0001) for colonoscopy versus sigmoidoscopy. Risk reduction was primarily among proximal tumors (adjusted HR 0.30; 95% CI, 0.16-0.57). Non-Hispanic black patients were at higher risk of postscreening CRC compared with non-Hispanic white patients (adjusted HR 1.71; 95% CI, 1.20-2.42); however, this disparity was noted only in the sigmoidoscopy cohort. Retrospective study with potential selection bias and residual confounding. Negative screening colonoscopy was associated with decreased incidence of subsequent CRC and a decrease in disparities compared with negative sigmoidoscopy findings in this large, community-based setting.

Su1125 Long-Term Efficacy of a pH-Dependent Release Mesalamine Formulation, Asacol in Patients With Ulcerative Colitis Who Showed Inadequate Response to a Time-Dependent Release Mesalamine Formulation, Pentasa: A Prospective Study

sigmoidoscopy and 43,677 with negative initial screening colonoscopy). Median age at initial screening exam was 57.9 (interquartile range [IQR] 53.1, 64.1). Women comprised 51.8% of the study cohort with 42.1% White, 24.2% Hispanic, 10.7% Black, and 9.7% Asian patients. Median duration of follow-up was 46.0 (IQR 22.7, 68.2) months with a total of 557,255 person-years of follow-up. A total of 246 colon cancers were detected during the study period. Median time to cancer diagnosis was 42.9 (24.2, 61.9) months. The adjusted hazard ratio of post-screening colorectal cancer among patients with negative colonoscopy vs. negative sigmoidoscopy was 0.4 (0.3, 0.6). Results of the adjusted Cox proportional hazards regression model are presented in Table 1. Conclusions: Among average-risk patients undergoing their initial screening exam, a negative screening colonoscopy was associated with significantly reduced risk of subsequent colon cancer compared to negative sigmoidoscopy. Adjusted Multivariable Cox Regression Analysis

Risk of colorectal tumor after negative baseline screening colonoscopy

Objective To review the following colonoscopy of negative baseline screening colonoscopy crowd,and to explore the risk of colorectal tumor at different time intervals in different gender,age and risk levels.Methods With bi-cohort study design,self-made questionnaire was used to survey the following colonoscopy of the asymptomatic average-risk population with negative baseline screening colonoscopy from January 1,1995 to December 31,2005.The survey contents included all the following colonoscopy,the risk stratification factors of colorectal cancer (age,gender,smoking status,history of diabetes,green vegetables intake,pickled food intake,fried smoked food intake,white meat intake).The life table survival analysis method was used to study the cumulative risk of colorectal tumor in different gender,age,risk levels.Results Four hundred and fifty-five cases were included,and there were 91 cases of colorectal polyp,24 cases of adenoma and 9 cases of advanced tumor.The cumulative prevalence rates of colorectal polyp,adenoma and advanced tumor during 5 years for negative baseline screening colonoscopy crowd were 11.9％,4.2％ and 2.0％ respectively.The cumulative prevalence rate of advanced tumor during 12 years was 3.9％.The risk of colorectal polyp of men was higher than that of female (x2 =8.142,P =0.004).The risk of colorectal polyp of ≥60 years group was higher than that of ＜60 years group (x2 =6.321,P =0.012).The risk of colorectal polyp of high risk group was higher than that of low risk group (x2 =4.082,P =0.043).Conclusion In the negative baseline screening colonoscopy crowd,5-year cumulative prevalence rates of colorectal polyp,adenoma,advanced tumor are low,and 12-year cumulative prevalence rate of colorectal advanced tumor is low too. Key words: Colorectal neoplasms; Colonoscopes

Quality Measures for Colonoscopy: A Critical Evaluation

In a recent article in The New York Times, "The $2.7 Trillion Medical Bill,"(1) colonoscopy was singled out for its cost. In their response, the leading gastroenterology professional societies highlighted colonoscopy's effectiveness and cost-effectiveness for the prevention of colorectal cancer (CRC). Affirming colonoscopy's central role in CRC prevention, both as a frontline test and as the final common pathway for other CRC screening modalities, requires strategies to measure and improve colonoscopy quality, particularly by controlling operator-dependent factors. Although colonoscopy is a powerful CRC screening test,(2-6) several recent studies have highlighted decreased protection, mainly against right-sided CRC,(5,7-16) an observation that has been linked to performance quality.

Colorectal cancer following negative colonoscopy: is 5-year screening the correct interval to recommend?

Despite the high sensitivity of screening colonoscopy, polyps and cancers can still go undetected. With the polyp-to-cancer transformation cycle averaging 7-10 years, present guidelines recommend repeat colonoscopy within 10 years after negative screening. However, not all colorectal malignancies follow this decade-long progression. This study evaluates the incidence and pathology of colorectal cancers following a previous negative screening colonoscopy. Records of patients who underwent a colectomy at our institution, from 1998 to 2009, were reviewed retrospectively. A total of 1,784 patient records were screened using exclusion criteria for inclusion in this study. The patients were divided as follows: Group 1 included patients with a negative colonoscopy within the previous 5 years; Group 2 included patients without a previous colonoscopy or with a previous colonoscopy more than 5 years prior. Group 1 patients were evaluated by colonoscopy for anemia, diverticulitis, signs of obstruction, and bleeding. Age, tumor location, operation performed, and pathology findings were recorded. The χ(2) test and paired t test were used for statistical analysis. A total of 233 patients were included in this study. Group 1 contained 43 patients with a mean age of 73 years (range = 35-94, median = 75). Group 2 had 190 patients with a mean age of 68 years (range = 19-91, median = 70). Group 1 consisted of 18 male and 25 female patients, and Group 2 included 94 male and 96 female patients. Both groups were further classified into the following age categories: <50 years, 50-80 years, and >80 years. Eighteen percent of the total study population had newly discovered colorectal cancer within a 5-year colonoscopy screening period. There were no significant differences in the distribution of the T and N stages between the two groups and no statistically significant differences when the rate of lymphovascular invasion (19 vs. 17 %; p = 0.39) and perineural invasion (7 vs. 11 %; p = 0.58) were compared. Within 5 years, 18 % of our study population developed colorectal cancer. Most of these malignancies were found within the 50-80-year age group and located predominantly in the right colon and distally in the sigmoid and rectum. While distal cancers may be visualized by flexible sigmoidoscopy, those located more proximally may be missed, necessitating the need for a full colonoscopy. Although staging was similar between the two groups, Group 1 tumors were less aggressive despite having appeared within 5 years. As a result of our incidence of colorectal cancer within a 5-year interval, a shorter period for routine colonoscopy may be considered.

Negative screening colonoscopy after a positive guaiac faecal occult blood test: not a contraindication to continued screening

In guaiac faecal occult blood test (gFOBT) screening at least 50% of positive individuals will have a colonoscopy negative for colorectal neoplasia. The question of continuing screening in this group has not been addressed. Data on participants aged 50-69 years with a positive gFOBT result and a negative colonoscopy were followed through the biennial screening pilot conducted between 2000 and 2007 in Scotland. In the first screening round, 1527 colonoscopies were negative for neoplasia. 1300 were re-invited in the second round, 905 accepted, and 157 had a positive gFOBT result, giving a positivity rate of 17.4%. Colonoscopy revealed 20 subjects with adenoma and six with invasive cancer. In the third screening round 1031 were invited for a third time and 730 accepted: 55 had a positive gFOBT test, giving a positivity rate of 7.5%. In this group, six colonoscopies revealed adenomas but there were no cancers diagnosed. In the third screening round, 108 individuals had had two positive gFOBT results and two subsequent negative colonoscopies. Eighty-four were invited for a third gFOBT, 66 accepted and 19 (25.6%) had a positive result none of whom had an adenoma or carcinoma. These data indicate that a negative colonoscopy following a positive gFOBT is not a contraindication for further screening, although this is likely to have a low yield of neoplastic pathology after two negative colonoscopies.

Overuse of Screening Colonoscopy in the Medicare Population

All relevant authorities recommend an interval of 10 years between normal screening colonoscopies. We assessed the timing of repeated colonoscopies after a negative screening colonoscopy finding in a population-based sample of Medicare patients. A 5% national sample of Medicare enrollees from 2000 through 2008 was used to identify average-risk patients undergoing screening colonoscopy between 2001 and 2003. Colonoscopy was classified as a negative screening examination finding if no indication other than screening were in the claims and if no biopsy, fulguration, or polypectomy was performed. Time to repeated colonoscopy was calculated. Among 24,071 Medicare patients who had a negative screening colonoscopy finding in 2001 through 2003, 46.2% underwent a repeated examination in fewer than 7 years. In 42.5% of these patients (23.5% of the overall sample), there was no clear indication for the early repeated examination. In patients aged 75 to 79 years or 80 years or older at the time of the initial negative screening colonoscopy result, 45.6% and 32.9%, respectively, received a repeated examination within 7 years. In multivariable analyses, male sex, more comorbidities, and colonoscopy by a high-volume colonoscopist or in an office setting were associated with higher rates of early repeated colonoscopy without clear indication, while those 80 years or older had a reduced risk. There were also marked geographic variations, from less than 5% in some health referral regions to greater than 50% in others. A large proportion of Medicare patients who undergo screening colonoscopy do so more frequently than recommended. Current Medicare regulations intending to limit reimbursement for screening colonoscopy to every 10 years would not appear to be effective.

A novel, noninvasive, mRNA gene expression colon cancer screening methodology.

3631 Background: An mRNA gene expression methodology testing noninvasive rectal swab samples for a panel of 16 genes, representing 4 metabolic pathways, has shown promise for detecting colon and rectal cancers in pilot studies. To test the screening potential of this methodology, we conducted a case-controlled, single-center study using samples collected from patients with a negative screening colonoscopy (Controls; n = 71) and from patients with colorectal cancer (CRC; n = 38). Methods: Controls were defined as polyp- and cancer-free patients with no family history of CRC. Rectal swabs were collected, coded, preserved in RNAProtect Ò solution (Qiagen), and RNA was isolated using RNeasy mini kit (Qiagen). Real time RT-PCR using reverse transcriptase (Invitrogen) and random primers and Oligo (dT) was performed on samples pretreated with RNAase-free DNase. PCR amplification with specific oligonucleotide primers was performed using Applied Biosystems 7500 Fast Real-Time PCR Systems for 16 different markers including CXCR2, osteopontin, cyclo-oxygenase-1 and 2, proliferating peroxisome activating receptor alpha, delta and gamma, growth- related oncogene alpha and gamma, interleukin-8, mCSF, p21, c-myc, CD44, cyclin D and serum amyloid A1. Classification was based on using Mahalanobis distances with a threshold set to ensure at least 90% sensitivity. Results: For the 71 controls, the median age was 57 years (range 50-81) and 37 were women. For the 38 cancer patients, the median age was 67 years (range 50-89) and 19 were women. Adenocarcinomas were identified in the following colon locations: cecum (10), ascending (10), transverse (3), sigmoid (12), and rectosigmoid (3). AJCC tumor stage was I (9); II (15): III (13); and IV (1). The final analysis results in a test performance with 92% sensitivity and 68% specificity using mean M-Distance calculation. Sensitivity is 92% and specificity is 60% using maximum M-Distance calculation. Conclusions: This mRNA gene expression methodology would fulfill current guidelines for screening which require a minimum sensitivity and specificity of 50%. Future studies will aim to improve the specificity and validate the technology. Author Disclosure Employment or Leadership Position Consultant or Advisory Role Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration IntelliGene Scan IntelliGene Scan IntelliGene Scan IntelliGene Scan IntelliGene Scan

Five-Year Risk of Colorectal Neoplasia after Negative Screening Colonoscopy

Five-Year Risk of Colorectal Neoplasia after Negative Screening Colonoscopy

A-Quarter-Century Experience of Screening Colonoscopy

Purpose: More than 25 years ago, we established colorectal cancer screening program using screening colonoscopy (SCS). The purpose of this study is to clarify detection rates of colorectal cancer (CRC) at first-time screening and intervals to detect CRC after negative screening. Methods: During a period between 1983 and 2008, 34,371 asymptomatic, average-risk individuals (male; 24,579, female; 9792, mean age at first-time screening; 48.7) were enrolled in the colorectal cancer screening program. Participation to first-time and repeated screening was voluntary. SCS was performed with skinny-caliber scopes (Olympus PCF) and sedation was applied only when indicated. Therapeutic interventions were performed, if clinically indicated. Totally, 125,006 screening colonoscopies were performed during this period. Records were reviewed to determine detection rates of CRC at initial and repeated colonoscopy, and intervals after negative colonoscopy to detect CRC at repeated colonoscopy. Results: Full colonoscopy to the cecum was successful in 123,529 (98.9%). At first-time SCS, CRC was detected in 241 cases (0.70%); 140 (0.41%) were limited in the mucosa and 101 (0.29%) were invasive. After negative SCS, 73 CRC were detected at repeated screening; 55 were limited in the mucosa and 18 were invasive. The intervals between negative screening and detection among these 18 invasive CRC were less than 1 year in 3 cases, 1-2 years in 5 cases, 2-3 years in 6 cases, 3-4 years in 2 cases, 4-5 years in 1 case, and over 10 years in 1 case. Conclusion: SCS using skinny-caliber scopes without sedation was well tolerated in the majority. First-time SCS effectively detected curable CRC. Interval to detect CRC after negative SCS was shorter than expected. We do not agree with currently recommended 10-year interval after negative colonoscopy.

Colon cancer screening and surveillance controversies

To discuss new colorectal cancer screening tests and highlight controversies regarding colon screening and surveillance. New screening guidelines were published in 2008. Tests that primarily detect early cancer include sensitive guaiac fecal occult blood test or fecal immunochemical test. Tests that can detect both early cancer and cancer precursor lesions include sigmoidoscopy and colonoscopy. One guideline endorses the use of computed tomographic colonography. Limitations of each test are highlighted in the new guidelines. Controversies include age to start screening, age to stop screening, and appropriate interval after a negative screening colonoscopy. New work has raised some doubt about the protective effect of colonoscopy in the proximal colon. Finally, there is new emphasis on the quality of screening programs. Colorectal cancer screening can reduce both incidence and mortality of colorectal cancer if performed with high quality. New work should focus on improving the quality of all screening programs.

Five-Year risk of colorectal neoplasia after negative screening colonoscopy

Five-Year risk of colorectal neoplasia after negative screening colonoscopy

Five-Year Risk of Colorectal Neoplasia After Negative Screening Colonoscopy

Recommendation for a 10-year interval for screening colonoscopy in persons at average risk for colorectal cancer is based on retrospective case–control data. There are no data from prospective studies of sufficient size and duration. This retrospective study determined the incidence of adenomas among individuals with no adenomas on baseline screening colonoscopy who were rescreened at a 5-year follow-up. The participants were 50 years or older and had undergone first-time screening from 1995 to 2000. The incidence of the following categories were determined: a cancer; an advanced adenoma (a tubular adenoma ≥1 cm in diameter, a polyp with high-grade dysplasia, or a villous component of at least 25%); a tubular adenoma ≤1 cm in diameter, a hyperplastic polyp; or no polyp. Among the 2983 persons screened for the first time, 2436 (81.7%) had no adenomas on baseline screening colonoscopy. At a mean of 5.3 ± 1.3 years later, 1256 of those with no adenomas (51.6%) underwent follow-up colonoscopy. At the time of baseline screening, the mean age of the participants was 56.7 years; 544 (43.3%) were women (mean age 57.1 years) and 712 (56.7%) were men (mean age 56.4 years). Among the 1256 persons re-screened, there were no cancers [95% confidence interval (CI) for the detection rate, 0% to 0.24%]. One or more neoplastic polyps were identified in 201 persons (16.0%). A total of 19 advanced adenomas were identified in 16 persons (1.3%). No significant difference was found at baseline in the risk of an advanced adenoma among persons without polyps [1.1% (12 of 1057)] and those with hyperplastic polyps [2.0% (4 of 199); relative risk, 1.77; 95% CI, 0.61–5.14]. The risk of any adenoma or an advanced adenoma was higher in men than women (relative risk, 1.88; 95% CI, 1.42–2.51 and 3.31; 95% CI, 1.02–10.8, respectively). For 1 advanced adenoma to be detected among all 1256 persons with normal findings at baseline, 79 would need to be rescreened at 5 years. Among women, 182 would need to be rescreened, whereas among men, 55 would need to be rescreened. These findings are consistent with previous data and support a rescreening interval of 5-years or longer after a normal colonoscopic examination in persons of average risk for colorectal cancer. The risk of an advanced adenoma is lower in women than in men.

Five-Year Risk of Colorectal Neoplasia after Negative Screening Colonoscopy

The appropriate interval for endoscopic rescreening after a negative colonoscopic examination is uncertain. We identified persons with no adenomas on baseline screening colonoscopy who returned at 5 years for follow-up colonoscopy. Findings were categorized according to the most advanced lesion present: no polyp, a hyperplastic polyp, a tubular adenoma less than 1 cm in diameter, an advanced adenoma (a tubular adenoma > or = 1 cm in diameter or a polyp with villous histologic features or high-grade dysplasia), or a cancer. Baseline screening colonoscopy had identified 2436 persons with no adenomas; 1256 of them (51.6%) were rescreened a mean (+/-SD) of 5.34+/-1.34 years later. The mean age of this group at baseline was 56.7 years; 56.7% of its members were men. No cancers were found on rescreening (95% confidence interval [CI] for the detection rate, 0 to 0.24%). One or more adenomas were found in 201 persons (16.0%). A total of 19 advanced adenomas, of which 10 (52.6%) were distal to the splenic flexure, were found in 16 persons (1.3%). The risk of an advanced adenoma did not differ significantly between persons with no polyps at baseline and those with hyperplastic polyps at baseline (1.1% [12 of 1057] and 2.0% [4 of 199], respectively; P=0.30). Men were more likely than women to have any adenoma (tubular less than 1 cm in diameter or advanced) (relative risk, 1.88; 95% CI, 1.42 to 2.51) and to have an advanced adenoma (relative risk, 3.31; 95% CI, 1.02 to 10.8). Among persons with no colorectal neoplasia on initial screening colonoscopy, the 5-year risk of colorectal cancer is extremely low. The risk of advanced adenoma is also low, although it is higher among men than among women. Our findings support a rescreening interval of 5 years or longer after a normal colonoscopic examination.

Screening and Surveillance Colonoscopy in Chronic Crohn's Colitis: Results of a Surveillance Program Spanning 25 Years

Since 1980, we have followed 259 patients with chronic Crohn's colitis in a prospective colonoscopic surveillance program. Our initial results through August 1998 showed a 22% chance of developing definite dysplasia or cancer by the fourth surveillance examination. We now update the results of all examinations since September 1998 until April 2005. All patients had at least 7 years of Crohn's colitis affecting at least one third of the colon. Patients were recalled every 1 to 2 years or sooner if dysplasia was found. Pathology was classified as normal, dysplasia (indefinite, low-grade [LGD], or high-grade [HGD]), or carcinoma. Lesions were classified as flat, polyp, or mass. A total of 1424 examinations were performed on 259 patients. Ninety percent had extensive colitis. The median age at diagnosis was 22 years (range, 2-61 y), and the median disease duration was 18 years (range, 7-49 y). On screening examination, definite dysplasia or cancer was found in 18 patients (7%). Thirteen had LGD, 2 had HGD, and 3 had cancer. On surveillance examinations, a first finding of definite dysplasia or cancer was found in an additional 30 patients (14%). Twenty-two had LGD, 4 had HGD, and 4 had cancer. The cumulative risk of detecting an initial finding of any definite dysplasia or cancer after a negative screening colonoscopy was 25% by the 10th surveillance examination. The cumulative risk of detecting an initial finding of flat HGD or cancer after a negative screening colonoscopy was 7% by the ninth surveillance examination. Periodic surveillance colonoscopy should be part of the routine management of chronic extensive Crohn's colitis.

Colonoscopy for screening and follow up of patients with a family history of colorectal cancer

To determine the minimum family history of colorectal cancer (CRC), which justifies colonoscopy and to establish whether further colonic assessment is necessary after a negative screening colonoscopy. A retrospective review of every colonoscopy undertaken for family screening at the Royal Berkshire and Battle Hospitals, Reading between October 1996 and July 2004. Four hundred and thirty-two patients (261 women) with an average age of 48 years (range 14-84) were screened. Three cancers in patients over the age of 60 years and 49 adenomas were found in 37 patients. Twenty three of 281 (8%) patients with a 'low-risk' family history (one in 12 or less lifetime risk of developing CRC) had either a cancer or an adenoma. Eighteen of 151 (12%) patients with a 'high-risk' family history (one in 10 or greater) had a similar positive colonoscopy. Thirteen of 15 patients who had an adenoma aged under 45 years had a high-risk family history. Seventy-three patients subsequently underwent two or more follow-up colonoscopies. There were 22 adenomatous polyps found in 12 patients (16%) at the first screening, nine adenomas in seven patients in the second colonoscopy and four adenomas found in four patients in all subsequent colonoscopies. Patients with a low-risk family history have a similar adenoma pick-up to that of the general population. These patients need not be screened below the age of 50 unless symptomatic. Follow up of low-risk family history (FH) patients with a negative screening colonoscopy is unlikely to be beneficial.

Study supports 20-year interval for colonoscopy screening

Patients with a negative colonoscopy result might not need to have another colonoscopy for 20 years or more, suggests a population-based, case–control study (Gut 2006; 55: 1145–50). Hermann Brenner and colleagues (German Cancer Research Centre, Heidelberg, Germany) compared the adjusted relative risks of colorectal cancer in 380 patients who had a previous negative colonoscopy with those in 485 control patients who had not undergone previous colonoscopy, according to time since colonoscopy. Patients with previous negative colonoscopy had a 74% lower risk of colorectal cancer than did those without previous colonoscopy (adjusted odds ratio 0·26; 95% CI 0·16–0·40). The risk remained low even when the colonoscopy had been done 20 or more years previously, Brenner and colleagues report. “These fi ndings should have an impact on future screening guidelines”, says Brenner. “There are virtually no data available on colorectal-cancer risk beyond 10 years after a negative screening colonoscopy, which has hindered recommendations of longer screening intervals.” According to John Marshall (Georgetown University, Washington, DC, USA), this study suggests that patients who have even one negative colonoscopy at some point in their lives have a low risk of developing colon cancer and that this conclusion seems justifi ed by the data. However, he cautions that only fi ve (1%) patients and 13 (3%) controls fell into the “over 20-year” category, on which researchers base part of their conclusions. “We must remember that the majority of patients diagnosed with colon cancer have later-stage disease, suggesting that we are failing to detect earlystage colon cancer in most patients”, says Marshall. “While one colonoscopy is better than none, one should not conclude from this study that one, and only one, colonoscopy will prevent colon-cancer deaths.”