Colonoscopic Screening in Average-Risk Individuals Ages 40 to 49 vs 50 to 59 Years

Background See CME quiz on page 1567. See Rex DK et al on page 506 in CGH; See CME quiz on page 1567. Colonoscopy is an effective and widely endorsed modality for screening for colorectal cancer. In recent years, colonoscopy was the primary driving force for the overall increase in colorectal cancer screening.1Phillips K.A. Liang S.Y. Ladabaum U. et al.Trends in colonoscopy for colorectal cancer screening.Med Care. 2007; 45: 160-167Crossref PubMed Scopus (111) Google Scholar There is compelling evidence that screening colonoscopy with removal of detected polyps leads to a substantial reduction in the incidence of colorectal cancer, with its efficacy rivaling or superior to annual fecal occult blood testing, flexible sigmoidoscopy, and double contrast barium enema.2Neugut A.I. Forde K.A. Screening colonoscopy: has the time come?.Am J Gastroenterol. 1988; 83: 295-297PubMed Google Scholar, 3Winawer S.J. Zauber A.G. Ho M.N. et al.Prevention of colorectal cancer by colonoscopic polypectomy The National Polyp Study Workgroup.N Engl J Med. 1993; 329: 1977-1981Crossref PubMed Scopus (4038) Google Scholar, 4Lieberman D.A. Weiss D.G. Bond J.H. et al.Use of colonoscopy to screen asymptomatic adults for colorectal cancer Veterans Affairs Cooperative Study Group 380.N Engl J Med. 2000; 343: 162-168Crossref PubMed Scopus (1644) Google Scholar Guidelines from multiple professional societies recommend screening colonoscopy beginning at age 50 years for average-risk individuals.5U.S. Preventive Services Task ForceScreening for colorectal cancer: recommendation and rationale.Ann Intern Med. 2002; 137: 129-131Crossref PubMed Scopus (562) Google Scholar, 6Winawer S. Fletcher R. Rex D. et al.Colorectal cancer screening and surveillance: clinical guidelines and rationale Update based on new evidence.Gastroenterology. 2003; 124: 544-560Abstract Full Text PDF PubMed Scopus (2009) Google Scholar, 7Smith R.A. Cokkinides V. Eyre H.J. American Cancer Society guidelines for the early detection of cancer, 2004.CA Cancer J Clin. 2004; 54: 41-52Crossref PubMed Scopus (241) Google Scholar This age cutoff is based largely on the fact that the incidence of colorectal cancer begins to rise in the sixth decade of life.8Matanoski G. Tao X.G. Almon L. et al.Demographics and tumor characteristics of colorectal cancers in the United States, 1998-2001.Cancer. 2006; 107: 1112-1120Crossref PubMed Scopus (67) Google Scholar However, given the long lead time associated with the adenoma to carcinoma progression, the increased number of colorectal cancers diagnosed in this age group may reflect the end result of adenomas present in individuals in their forties. Hence, these cancers may be prevented by colonoscopy with polypectomy of premalignant lesions in the preceding decade. Despite this theoretic argument for screening individuals in their forties, only one prior study has investigated the prevalence of colorectal neoplasia with colonoscopic screening in asymptomatic average-risk individuals aged 40–49 years in the United States.9Imperiale T.F. Wagner D.R. Lin C.Y. et al.Results of screening colonoscopy among persons 40 to 49 years of age.N Engl J Med. 2002; 346: 1781-1785Crossref PubMed Scopus (322) Google Scholar In this study, we investigated the prevalence of colorectal neoplasia, including potentially premalignant adenomas, in asymptomatic individuals at average risk aged 40–49 years undergoing colonoscopic screening and compared it with findings in individuals aged 50–59 years. Executive Health Exams International, Inc. (EHE) is a company that provides annual physical examinations to individuals employed at corporations that offer EHE services as part of their corporate wellness plan. The examinations are offered to the employees of participating companies at no cost to the employee. Companies differ in their policies regarding which levels of employees are eligible for the physical examination, but many companies offer it to all levels of employees and their spouses. The physical examinations take place at 6 EHE owned centers (New York City, NY; Stamford, CT; Morristown, NJ; Houston, TX; Chicago Il; and Boston, MA) and at a network of over 60 physician offices across the country. The network offices meet EHE quality control standards for the examination procedures. Examination data are recorded electronically in a centralized digital medical record system maintained by EHE. Data can be retrieved from the centralized digital medical record system and are stripped of identifiers before being compiled into files that can be read by standard statistical programs. The Columbia University Medical Center Institutional Review Board approved the study protocol and designated it as “Non-Human Research” involving deidentified records previously collected for other purposes. Colonoscopy screening is provided as part of the wellness examination for all adults over age 40 years. At the time of initial examination, examinees fill out a questionnaire, which collects demographic, risk factor, and clinical history information. Those 40 years of age and older who are eligible and agreeable are then scheduled to return for their colonoscopic examination. We collected deidentified data on colonoscopies performed on individuals ages 40–49 years as well as individuals ages 50–59 years during the 27-month period from January 2004 through March 2006. We excluded colonoscopies that did not reach the cecum as well as colonoscopies for which the clinical indication was other than for screening purposes (eg, anemia, abdominal pain, or diarrhea). To ensure that the population was of average risk, we excluded from the analysis individuals who had a family history of colon cancer or a personal history of inflammatory bowel disease or any malignancy other than skin cancer. We collected data on the size, location, and number of adenomas per patient from the colonoscopy reports. The presence of adenomatous polyps, villous features, high-grade dysplasia, and carcinoma was defined by pathology review. Adenoma size was determined by visual estimate with the use of the open biopsy forceps or was determined after removal. Adenomas considered advanced were those that were ≥1 cm in diameter or that contained villous features or high-grade dysplasia. In instances in which an individual had multiple adenomas, we reported information on the largest. In instances in which 2 or more adenomas were the same size, information on the most distal was reported. We compared the prevalence and location of colorectal adenomas, advanced adenomas, and carcinomas among individuals 40–49 years to those 50–59 years. We used the χ2 and Fischer exact tests for comparisons of proportions. A total of 905 colonoscopies was performed during the study period that were eligible for analysis. Of these, 553 colonoscopies were of patients ages 40–49 years, and 352 colonoscopies were of patients ages 50–59 years. The demographics of the subjects included in the analysis are listed in Table 1. Both groups were predominantly male (75% in the 40–49 group and 77% in the 50–59 group) and were drawn largely from New York City and Houston, TX. The preparation was characterized as excellent or average in 87% of patients in the 40–49 years age bracket and in 85% of the 50–59 years age bracket (P = .70). Moderate or extreme technical difficulty was reported in 11% and 13% of the patients in the 40–49 and 50–59 years age brackets, respectively (P = .56).Table 1Demographics of Subjects Undergoing Screening ColonoscopyAges 40−49 y n = 553Ages 50−59 y n = 352Age, yMedian, 45.58Median, 53.71Range, 40.13−49.99Range, 50.03−59.74Sex, n (%) Male417 (75)271 (77) Female136 (25)81 (23)Race, n (%) White393 (71)258 (73) Nonwhite160 (29)94 (27)Body size, n (%) Normal weight191 (36)110 (33) Overweight258 (49)154 (47) Obese79 (15)68 (21) Open table in a new tab A total of 135 patients had 1 or more adenomas with a uniform prevalence of findings by age group. The prevalence of adenomas in the 2 age brackets is illustrated in Table 2. Among the 40–49 years age group, 79 (14%, 95% confidence interval CI: 12%–18%) individuals had 1 or more adenomas, and, among the 50–59 years age group, 56 (16%, 95% CI: 12%–20%) had 1 or more adenomas (P = .50). After controlling for sex, race, body size, and clinical facility location, age group remained unassociated with adenoma prevalence (P = .52). In the 40–49 years age group, 11 of these patients (2% of the total screened, 95% CI: 1%–4%) had an advanced neoplasm, whereas, in the 50–59 years age group, 13 of the patients had an advanced neoplasm (4% of the total screened, 95% CI: 2%–6%). The number needed to screen to find 1 advanced neoplasm in the 40–49 years age group is 50 (95% CI: 29–100), and, in the 50–59 years age group, the number is 27 (95% CI: 16–50). Among the 40–49 years age group, men accounted for 73% of the advanced lesions, and, among the 50–59 years age group, men accounted for 69% of the advanced lesions (P = .85). There was 1 adenocarcinoma found in the entire cohort, occurring in the 50–59 years age group, yielding a carcinoma prevalence of 0.3% in this age group. The prevalence of advanced colorectal neoplasia did not differ significantly between the 2 age groups (P = .12). In the 40–49 years age group, the prevalence of 1 or more adenomas among women was 11% and among men was 15% (P = .21), and, in the 50–59 years age group, the prevalence was 15% in men and 16% in women (P = .76).Table 2Number of Patients With No Adenoma, 1 or More Adenoma, and 1 or More Advanced NeoplasmAges 40−49 y, n (%)Ages 50−59 y, n (%)No adenoma474 (86)296 (84)Nonadvanced adenoma68 (12)43 (12)Advanced neoplasia11 (2)13 (4)NOTE. There was no statistically significant difference between the 2 age brackets with regard to prevalence of adenomas (P = .50) or prevalence of advanced adenomas (P = .12). Open table in a new tab NOTE. There was no statistically significant difference between the 2 age brackets with regard to prevalence of adenomas (P = .50) or prevalence of advanced adenomas (P = .12). The distribution of the number of adenomas per patient is illustrated in Table 3. Of the 40–49 years age group with adenomas, 57 (72%) had 1 adenoma, 17 (22%) had 2 adenomas, and 5 (6%) had 3 or more adenomas. Of the 50–59 years age group with adenomas, 45 (80%) had 1 adenoma, 8 (14%) had 2 adenomas, and 3 (5%) had 3 or more adenomas. The difference in adenoma number between these 2 age groups was not statistically significant (P = .53). The average and median adenoma size did not vary by group (40–49 years age group mean, 4.82 mm; median, 4.00 mm; 50–59 years age group mean, 5.05 mm; median, 4.00 mm, P = .78). The prevalence of adenomas greater or equal to 5 mm in size was 43% in the 40–49 years age bracket and 45% in the 50–59 years age bracket (P = .85).Table 3Number of Patients With 1, 2, or ≥3 Adenomas Among Patients With Adenomas in the 2 Age BracketsNumber of adenomasAges 40−49 y, n (%)Ages 50−59 y, n (%)One adenoma57 (72)45 (80)Two adenomas17 (22)8 (14)Three or more adenomas5 (6)3 (5)NOTE. P = .53 for the difference in adenoma number. Open table in a new tab NOTE. P = .53 for the difference in adenoma number. The distribution of adenomas throughout the colon in the 2 groups is detailed in Table 4 and did not vary by age group (P = .37). The largest adenomas found within an individual were present proximal to the splenic flexure in 47% and 59% of the 40–49 and 50–59 years age groups, respectively (P = .17). Among those with adenomas, the prevalence of individuals without adenomas at or distal to the splenic flexure was 41% in the 40–49 years age group and 54% in the 50–59 years age group (P = .13).Table 4Prevalence of Adenomas by Location and Age GroupAge group, yLocation, n (%)RectumSigmoidDescending colonSplenic flexureTransverse colonHepatic flexureAscending colonCecum40−498 (10)13 (17)10 (13)11 (14)12 (15)8 (10)11 (14)6 (8)50−595 (9)8 (14)4 (7)6 (11)6 (11)6 (11)8 (14)13 (23)NOTE. The difference in distribution of adenomas in these 2 age groups was not statistically significant (P = .37). Open table in a new tab NOTE. The difference in distribution of adenomas in these 2 age groups was not statistically significant (P = .37). Despite the substantial morbidity associated with colorectal cancer and the widespread adoption of screening recommendations that apply to asymptomatic average-risk persons at age 50 years, the prevalence of preneoplastic colorectal adenomas in the preceding decade has had little study. The sole previous analysis of the prevalence of adenomas in this age group in the United States found an adenoma prevalence of 11%, with a prevalence of advanced adenomas of 3.5%, rates similar to our findings (Table 5).9Imperiale T.F. Wagner D.R. Lin C.Y. et al.Results of screening colonoscopy among persons 40 to 49 years of age.N Engl J Med. 2002; 346: 1781-1785Crossref PubMed Scopus (322) Google Scholar Similar findings in this age group were reported among average-risk men in South Korea, although, in that study, the prevalence of adenomas and advanced neoplasia among women was significantly lower.10Kim S.E. Shim K.N. Jung S.A. et al.An association between obesity and the prevalence of colonic adenoma according to age and gender.J Gastroenterol. 2007; 42: 616-623Crossref PubMed Scopus (55) Google ScholarTable 5Prevalence of Adenomas, Advanced Neoplasms, and Colorectal Cancer Among Patient Groups Aged 40−49 and 50−59 YearsStudyPercentage of patients with adenomasPercentage of patients with advanced neoplasmsPercentage of patients with colorectal cancerCurrent study40−49 y: 1440−49 y: 240−49 y: 050−59 y: 1650−59 y: 450−59 y: 0.3Imperiale et al9Imperiale T.F. Wagner D.R. Lin C.Y. et al.Results of screening colonoscopy among persons 40 to 49 years of age.N Engl J Med. 2002; 346: 1781-1785Crossref PubMed Scopus (322) Google Scholar40−49 y: 1140−49 y: 3.540−49 y: 050−59 y: not stated50−59 y: 4.150−59 y: 0.5 Open table in a new tab Prior studies of asymptomatic patients older than 50 years found a prevalence of adenoma and advanced neoplasia that was considerably higher than that in our cohort. For example, in one large cohort, the prevalence of colorectal neoplasia was 37.5%.4Lieberman D.A. Weiss D.G. Bond J.H. et al.Use of colonoscopy to screen asymptomatic adults for colorectal cancer Veterans Affairs Cooperative Study Group 380.N Engl J Med. 2000; 343: 162-168Crossref PubMed Scopus (1644) Google Scholar However, more than two thirds of this cohort consisted of subjects between 60 and 75 years of age. Moreover, 13.9% of individuals in that population had 1 or more first-degree relatives with a history of colorectal cancer. Other cohorts demonstrating a similarly high prevalence of adenomas among asymptomatic patients older than 50 years had a large proportion of patients older than 59 years and included those with a family history of colorectal cancer.11Imperiale T.F. Wagner D.R. Lin C.Y. et al.Risk of advanced proximal neoplasms in asymptomatic adults according to the distal colorectal findings.N Engl J Med. 2000; 343: 169-174Crossref PubMed Scopus (936) Google Scholar, 12Barclay R.L. Vicari J.J. Doughty A.S. et al.Colonoscopic withdrawal times and adenoma detection during screening colonoscopy.N Engl J Med. 2006; 355: 2533-2541Crossref PubMed Scopus (1150) Google Scholar Our study excluded such patients to compare the prevalence of colorectal neoplasia in 2 age deciles in an average-risk population. This most likely accounts for the relatively lower prevalence of adenomas in our cohort as compared with prior studies. We did not find a significant difference in the overall prevalence of adenomas between the 40–49 years age group and the 50–59 years age group. However, we did observe an increase in the prevalence of advanced neoplasms in the 50–59 years age group compared with the 40–49 years age group. Although this near doubling of the prevalence of advanced neoplasms was not statistically significant, we suspect that there is a true rise in the prevalence of advanced neoplasms between these 2 that our study was not to that the difference in the prevalence of advanced that be with was in the 40–49 years age group vs in the 50–59 years age group. This rise was as well in the study by et in which the rise in prevalence of advanced neoplasms in of T.F. Wagner D.R. Lin C.Y. et al.Results of screening colonoscopy among persons 40 to 49 years of age.N Engl J Med. 2002; 346: 1781-1785Crossref PubMed Scopus (322) Google Scholar A rise in the prevalence of advanced neoplasms in the 50–59 years age group as compared with the 40–49 years age group for the rise in the prevalence of colorectal cancer in analysis of colonoscopy for colorectal cancer screening is to screening the asymptomatic population beginning at age 40 years morbidity and to be such performed on colonoscopy as a screening modality but considered age 50 years to be the age of of et of screening for colorectal cancer in the 2000; PubMed Scopus Google Scholar, of colonoscopy in screening for colorectal Intern Med. 2000; PubMed Scopus Google Scholar with only one such analysis screening at age R. et of colonoscopic screening for colorectal cancer at J Gastroenterol. 2000; PubMed Google Scholar A recent study by et the results of a screening in found that the prevalence of advanced colorectal neoplasia in men ages 40–49 years was similar to that of women ages 50–59 years, that the age at which to screening be et in screening for detection of advanced Engl J Med. 2006; 355: PubMed Scopus Google Scholar However, individuals in the 40–49 years age bracket in that study were eligible for screening only there was a family history of cancer of any this not the average-risk the analysis to those with a family history of malignancy other than colorectal cancer. our results are similar in among the prevalence of adenoma was the same in the 2 age groups and was higher among 50–59 years of age women than among 40–49 years of age Our study has a number of the population is predominantly male and the to and as a risk for colorectal neoplasia of a of and which may of adenomas, were not one not there to be a large difference in or use between the 2 age brackets that a substantial on our this was an study, the of the patient to with colonoscopy during ages 40–49 years may to associated with an increased risk of adenoma or such as We excluded from our analysis those patients who were to an indication for colonoscopy other than but the that of the patients in the 40–49 years of age bracket were of risk for colorectal our study on an employed population provided with wellness examinations by their the results may not be to other Our analysis that there is little difference in the overall prevalence of colorectal adenomas we compared asymptomatic individuals ages 40–49 years to those ages 50–59 years. Despite the similar adenoma prevalence between the 2 age groups, we detected an increased prevalence of advanced neoplasia in the 50–59 years age group that was not statistically significant, of size We suspect that studies a true rise in the prevalence of advanced neoplasia these 2 age studies are to the of screening with colonoscopy at age 40 years and to to risk those we to be at average risk for colorectal cancer. Medical PDF