First-degree relatives of patients with advanced colorectal adenomas have an increased prevalence of colorectal cancer.

BACKGROUND & AIMS: The risk of colorectal cancer in relatives of patients with adenomatous colonic polyps is not well defined. This study assessed whether finding colonic neoplasia during screening colonoscopy was related to the family history of colorectal cancer among the participants' parents and siblings. METHODS: Self-reported family history of colorectal cancer was recorded for all participants in a screening colonoscopy study. The size and location of all polyps were recorded before their removal and histologic examination. Participants were grouped according to the most advanced lesion detected. RESULTS: Three thousand one hundred twenty-one patients underwent complete colonoscopic examination. Subjects with adenomas were more likely to have a family history of colorectal cancer than were subjects without polyps (odds ratio [OR], 1.36; 95% confidence interval [CI], 1.09-1.70). The finding of a small (<1 cm) tubular adenoma as the most advanced lesion was associated with only a modest increase in the OR of colorectal cancer in family members (OR, 1.26; 95% CI, 0.99-1.61), but the presence of an advanced adenoma was associated with a higher OR (OR, 1.62;5% CI, 1.16-2.26). Younger age of adenoma diagnosis was not related to a higher prevalence of a family history of colorectal cancer. CONCLUSIONS: Relatives patients with advanced colorectal adenomas have an increased risk of colorectal cancer. Individuals with advanced colorectal adenomas should be counseled about the increased risk of colorectal cancer among their relatives.     

Risk factors for colorectal adenomas among immediate family members of patients with colorectal cancer in Taiwan: a case-control study

OBJECTIVES: The incidence of colorectal cancer or adenoma among first-degree relatives of patients with colorectal cancer is significantly high. However, a well defined screening and surveillance consensus has not been developed for these families in Taiwan. We conducted this study to evaluate the colorectal adenoma prevalence pattern in screened immediate family members in Taiwan, and to derive implications for future screening programs. METHODS: A total of 234 immediate family members (aged 51.6 +/- 21.5 yr) of 186 patients with colorectal cancer were offered a colonoscopy. Each relative examined was then paired with two control subjects for age, sex, and symptoms. The prevalence of colorectal adenomas was then compared using multiple logistic regression analysis. RESULTS: The estimated risk of developing adenomas among immediate family members of patients with colorectal cancer was significantly increased (OR = 2.33; 95% CI, 1.43-3.78; p < 0.001). This trend was more striking for men (OR = 2.46; 95% CI, 1.40-4.31; p = 0.001). Immediate family members were at an increased risk for high-risk adenomas (> or = 1.0 cm, with a villous component, and/or with severe dysplasia) (OR = 4.5; 95% CI, 1.91-10.60; p = 0.002), and developed adenomas at an earlier age than did controls. Individuals with index cancer relatives diagnosed at < 50 yr of age or male relatives posed a higher risk of developing colorectal adenomas. CONCLUSIONS: The prevalence of colorectal adenoma in persons with a colorectal cancer family history in Taiwan is similar to that reported in Western countries. This high-risk population should be offered a screening colonoscopy beginning at 40 yr of age.     

Screening colonoscopy in 40- to 50-year-old first-degree relatives of patients with colorectal cancer is efficient: a controlled multicentre study

Background and aims Persons with a familial risk of colorectal cancer (CRC) account for about 25% of all CRC cases. The adenoma prevalence in relatives of CRC patients 50–60 years of age is 17–34%; data on younger individuals are scarce. Our aim was to prospectively define the adenoma prevalence in 40- to 50-year-old first-degree relatives of CRC patients compared to controls.Patients and methods CRC patients were identified via the regional cancer registry, and their 40- to 50-year-old first-degree relatives (risk group) were invited for screening colonoscopy. Additional probands and controls of the same age were recruited by newspaper articles and radio or television broadcastings. Using high-resolution video colonoscopy, each detected polyp was removed and histopathologically assessed. Each participant completed demographic and epidemiological questionnaires. Results Of 228 subjects in the risk group 36.4% had polypoid lesions compared to 20.9% of 220 controls (p<0.001). Forty-three (18.9%) subjects in the risk group had adenomas compared to 18 (8.2%) in the control group (p=0.001). High-risk adenomas (>10 mm and/or of villous type) were found in 12 persons in the risk group compared to 5 controls (not significant). In the risk group most lesions (52%) were located proximal to the sigmoid colon compared to 29% in controls.Conclusions Subjects between 40–50 years with first-degree relatives with CRC demonstrate a significantly higher prevalence of adenomas than controls, with a tendency towards a more proximal location. These data support a screening colonoscopy in persons with familial risk already between 40 and 50 years.     

Screening colonoscopy among persons 50 to 60 years of age with and without familial risk of colorectal cancer - a prospective multicenter trial

BACKGROUND: In Germany screening colonoscopy was introduced into the National program on colorectal cancer prevention in Oktober 2002. The prevalence of neoplasia in patients with and without familiar risk was determined together with patient satisfaction with screening colonoscopy. Methods: Asymptomatic subjects from 50 to 60 years underwent screening colonoscopy and were stratified in two groups with and without familiar risk (first-degree relatives with CRC) in a multicenter trial among German gastroenterologists. Advanced neoplasia was defined as an adenoma at least 1 cm in diameter, a villous adenoma, an adenoma with high-grade dysplasia, or invasive cancer. After recovery from sedation all subjects were asked if they would agree to a control colonoscopy and the pain score was recorded on a scale from 0 to 6. Results: A total of 557 subjects (322 at average risk and 235 with familiar risk) underwent screening colonoscopy. The prevalence of advanced neoplasia in subjects without/with familiar risk was not significantly different in persons from 50 to 54 years (9 vs. 15 %) in contrast to persons from 55 to 60 years (10 vs. 22 %, p = 0.004) where the relative risk was doubled. Compared to younger patients, the prevalence of all neoplasia (including small adenomas) was significantly different only for older patients with familiar risk (44 vs. 23 %, p < 0.0001). The mean value of the pain-score was 0.76 + 1.0. Subjects examined without medication had significantly higher pain scores than subjects under medication. Colonoscopy performed under disoprivan resulted in similar pain-scores compared to midazolam at dosages > 5 mg. All patients agreed to a control colonoscopy. CONCLUSION: Screening colonoscopy is an effective and well-accepted method. The high prevalence of advanced neoplasia even in persons from 50 to 54 years suggests that screening should start at the age of 50.     

Prevalence of clinically important histology in small adenomas.

BACKGROUND & AIMS: The prevalence of advanced histology in small polyps has become a crucial issue in optimizing colorectal cancer screening strategies, especially in view of the advent of computed tomography colonography. We evaluated the prevalence of advanced histology in small and diminutive adenomas to clarify their clinical importance in terms of malignant potential. METHODS: Data were reviewed retrospectively from 3291 colonoscopies performed on asymptomatic patients found to have an adenoma on screening with flexible sigmoidoscopy a few weeks before the colonoscopy or who had a family history of colorectal cancer. All polyps were excised endoscopically and sent for pathology testing. Specimens with advanced histology were confirmed by a second reading. RESULTS: Of the 3291 colonoscopies performed, 1235 colonoscopies yielded a total of 1933 small or diminutive adenomatous polyps. Advanced histology including carcinoma was found in 10.1% of small (5-10 mm) adenomas and in 1.7% of diminutive adenomas (< or = 4 mm). Carcinoma was found in .9% of small adenomas, and 0% of diminutive adenomas. Of the 107 patients found to have polyps 2-10 mm with advanced histology, 100 (93%) were referred for colonoscopy because of an adenoma found on a recent screening with flexible sigmoidoscopy. Seven patients underwent colonoscopy for a positive family history of colon cancer; all 7 had a single affected first-degree relative older than age 50. CONCLUSIONS: Adenomas 5-10 mm in size harbor pathologically significant histology, and the need for removal of these lesions must be addressed to optimize colorectal cancer prevention.     

A screening clinic for relatives of patients with colorectal cancer in a district general hospital.

A family cancer screening clinic was set up to screen and counsel subjects at above average risk of developing colorectal cancer. Criteria for referral were one first degree relative under 50 years or two of any age with colorectal cancer. Pedigree information was used to estimate lifetime risks of developing colorectal cancer and offer appropriate screening: colonoscopy for high risks (greater than 1 in 10), faecal occult blood testing for lower risks. One hundred and eleven subjects from 76 families were seen over four years. Forty two families gave a pedigree consistent with dominantly inherited non-polyposis colorectal cancer syndrome (HNPCC). Three subjects from one family were found to have familial adenomatous polyposis. Ninety two colonoscopies yielded 21 patients with polyps (12 had tubular adenomas, including one with early malignant invasion). Thirty three per cent (four of 12) of the tubular adenomas were beyond the reach of a flexible sigmoidoscope. Three hundred and forty two further high risk relatives were identified from the family history.     

Is colonoscopic screening appropriate in asymptomatic patients with family history of colon cancer?

Colonoscopy has been advocated by some investigators as the most appropriate means of screening asymptomatic patients with a positive family history of colorectal cancer. However, results of such screening have been widely disparate. The purpose of this study was to evaluate the yield of colonoscopy in a cohort of completely asymptomatic individuals with one or two first-degree relatives with a history of colorectal cancer and to compare this yield with that of colonoscopy in a group of patients with apparent anal bleeding. Patients with possible genetic disorders, such as familial polyposis, were excluded. A total of 160 asymptomatic patients and a comparison group of 137 patients with nonacute anorectal bleeding underwent colonoscopy. Colonoscopy was completed in 143 of the 160 study patients (89 percent) and in all of the comparison patients and did not result in any complications. Twenty-two adenomas were found in 17 study patients (10.6 percent); 16 of the 22 adenomas were less than 1 cm in size. In the comparison group, eight adenomas were identified (5.8 percent of patients). No cancers were identified. The difference in polyp frequency between groups was not significant. The relatively low yield of colorectal neoplasms discovered at colonoscopy in this study may in part be due to the small sample size or to the strict criteria used to define these asymptomatic patients but does not lend strong support to the notion that colonoscopy is an appropriate first step in screening the asymptomatic patient with one or two first-degree relatives with colon cancer.     

Colonoscopic screening of first-degree relatives of patients with large adenomas: increased risk of colorectal tumors

BACKGROUND & AIMS: The risk of developing colorectal neoplasia is not well established among family members of individuals with large adenomas, and screening strategies remain under debate in this population. This study aimed at quantifying the risk of colorectal adenomas and cancers using colonoscopic screening in first-degree relatives of patients with large adenomas. METHODS: This case-control study was performed in 18 endoscopic units of French nonuniversity hospitals. A colonoscopy was offered to first-degree relatives of 306 index cases with adenomas > or =10 mm if they were alive, aged 40-75 years, and could be contacted by the index case. Among them, 168 were examined and matched for age, sex, and geographical area with 2 controls (n = 307). Controls were randomly selected from 1362 consecutive patients aged 40-75 years having undergone a colonoscopy for minor symptoms. RESULTS: The prevalence of large adenomas and cancers was 8.4% and 4.2%, in relatives and controls, respectively. Odds ratios (ORs) associated with a history of large adenomas in relatives were 2.27 (95% confidence interval [CI], 1.01-5.09) for cancers or large adenomas, 1.21 (95% CI, 0.68-2.15) for small adenomas, and 1.56 (95% CI, 0.96-2.53) for all colorectal neoplasia. The risk of large adenomas and cancers was higher in relatives of index cases younger than 60 years (OR, 3.82; 95% CI, 0.92-15.87) and when the index case had large distal adenomas (OR, 3.14; 95% CI, 1.27-7.73). CONCLUSIONS: First-degree relatives of patients with large adenomas are at increased risk of developing colorectal cancers or large adenomas. This result has implications for screening in this high-risk population.     

Colorectal cancer screening: Results of a 5-year program in asymptomatic subjects at increased risk

BACKGROUND AND AIMS: The province of Ferrara has one of the highest incidences of colorectal cancer (CRC) in Italy. In January 2000, we set up a colonoscopy screening program focussing on first-degree relatives of CRC patients. We now report the results 5 years after the beginning of the project. SCREENEES AND METHODS: In October 1999, we started a campaign stressing the usefulness of colonoscopy for the first-degree relatives of CRC patients. Subjects included in the screening program were aged between 45 and 75 years with at least one first-degree relative affected by CRC. They were invited to an interview where a physician suggested colonoscopy as a screening option. RESULTS: In 5 years, 776 subjects were interviewed and 733 (94.4%) agreed to an endoscopic examination (M/F:375/401; mean age 55 years): 562 colonoscopies were performed. Adenomas and cancers were found in 122 (21.7%) and 12 (2.1%) subjects, respectively. Histological examination in 181 persons with lesions (32.8%) showed (most serious lesion quoted) 47 hyperplastic polyps (26% of all lesions), 2 serrated adenomas (1.1%), 68 tubular adenomas (48%), 24 tubulovillous adenomas (13.3%), 9 adenomas with high grade dysplasia (5%) and 12 adenocarcinomas (6.6%). The majority of the cancers were at an early stage (8 Dukes A and 3 Dukes B). Sedation was used in only 42 colonoscopies (7.5%). CONCLUSIONS: A colonoscopy-based screening in this selected high-risk population is feasible. Even without sedation subjects readily agreed to the endoscopic procedure. We identified a significant number of advanced neoplasms and cancers at an early stage suggesting that this could be a useful tool in early identification of CRC.     

Incidence and recurrence rates of colorectal adenomas in first-degree asymptomatic relatives of patients with colon cancer

OBJECTIVES: Subjects with one first-degree relative affected with colorectal cancer are considered to be at increased risk of colorectal adenomas. We compared the recurrence and incidence rates of colorectal adenomas among subjects with one first-degree relative with colorectal cancer and those without family history. METHODS: A series of consecutive asymptomatic subjects successfully underwent a colonoscopy, were found to have either normal results or at least one adenoma, provided a detailed family history, and were offered a second colonoscopy 3 yr later; 190 out of 436 subjects accepted, 134/172 with one or more adenomas and 56/264 with no abnormalities at the initial examination. A first-degree family history was reported by 43/134 and 26/56, respectively. RESULTS: By multivariate analysis, the presence of adenomas at follow-up examination was significantly associated with a positive family history of colorectal cancer in both subgroups, those with a previously resected adenoma (odds ratio = 2.23, 95% CI = 1.04-4.79) and those without (odds ratio = 8.95, CI = 1.29-62.22). CONCLUSION: A history of one first-degree relative with colorectal cancer is associated with a significant increase in 3-yr cumulative incidence and recurrence rates of adenomas.     

Five-year colon surveillance after screening colonoscopy

BACKGROUND & AIMS: Outcomes of colon surveillance after colorectal cancer screening with colonoscopy are uncertain. We conducted a prospective study to measure incidence of advanced neoplasia in patients within 5.5 years of screening colonoscopy. METHODS: Three thousand one hundred twenty-one asymptomatic subjects, age 50 to 75 years, had screening colonoscopy between 1994 and 1997 in the Department of Veterans Affairs. One thousand one hundred seventy-one subjects with neoplasia and 501 neoplasia-free controls were assigned to colonoscopic surveillance over 5 years. Cohorts were defined by baseline findings. Relative risks for advanced neoplasia within 5.5 years were calculated. Advanced neoplasia was defined as tubular adenoma greater than > or =10 mm, adenoma with villous histology, adenoma with high-grade dysplasia, or invasive cancer. RESULTS: Eight hundred ninety-five (76.4%) patients with neoplasia and 298 subjects (59.5%) without neoplasia at baseline had colonoscopy within 5.5 years; 2.4% of patients with no neoplasia had interval advanced neoplasia. The relative risk in patients with baseline neoplasia was 1.92 (95% CI: 0.83-4.42) with 1 or 2 tubular adenomas <10 mm, 5.01 (95% CI: 2.10-11.96) with 3 or more tubular adenomas <10 mm, 6.40 (95% CI: 2.74-14.94) with tubular adenoma > or =10 mm, 6.05 (95% CI: 2.48-14.71) for villous adenoma, and 6.87 (95% CI: 2.61-18.07) for adenoma with high-grade dysplasia. CONCLUSIONS: There is a strong association between results of baseline screening colonoscopy and rate of serious incident lesions during 5.5 years of surveillance. Patients with 1 or 2 tubular adenomas less than 10 mm represent a low-risk group compared with other patients with colon neoplasia.     

A Scoring System for the Strength of a Family History of Colorectal Cancer

BACKGROUND Family history of colorectal cancer is associated with an increased risk for the disease, although there are many combinations of family history that are hard to correlate with risk status. A scoring system for family history of colorectal cancer was designed to make risk more readily quantifiable.METHODS A colonoscopy database was used to test the following points system: each first-degree relative with colorectal cancer = 3 points; each second-degree relative with colorectal cancer = 1 point. Families with one or more first-degree relative affected under 50 years of age = an extra 3 points. Families with one or more second-degree relative affected under 50 years of age = an extra 1 point. Families with multiple relatives on the same side of the family = an extra 3 points (first-degree relatives), 1 point (second-degree relatives), or 2 points (first-degree and second-degree relatives). Points were added and categories defined as follows: low risk, 1 to 4 points; medium risk, 5 to 7 points; high risk, 8 to 10 points; very high risk, >10 points. A control group of average-risk patients having screening colonoscopy was used. Categories were compared in number of adenomas, hyperplastic polyps, and cancers.RESULTS The records of 992 patients were used to test the system. Mean adenomas per patient per group were 0.4 for controls, 1.0 for low risk, 1.0 for medium risk, 1.7 for high risk, and 1.7 for very high risk. Cancers per group were 2 of 196 for controls, 8 of 513 for low risk, 3 of 171 for medium risk, 3 of 84 for high risk, and 1 of 28 for very high risk. The score categories were combined to produce revised risk levels of low (score 1 to 7) and high (>7). Average adenomas per patient in the revised categories were 0.4 (control), 1.0 (low risk), and 1.7 (high risk). The odds ratio of having one to two adenomas was 1.73 (1.19–2.50, 95% confidence limits) in the low-risk group and 2.39 (1.41–4.01) in the high-risk group. Odds ratios for having three or more adenomas were 5.70 (2.44–13.32) in the low-risk group and 10.35 (3.97–26.97) in the high-risk group.CONCLUSION In the two-category system proposed here of quantifying familial risk of colorectal cancer, patients having less than 8 points were at low risk and those with 8 or more were at high risk. Surveillance and chemoprevention protocols can be designed through use of these risk categories. A scoring system for family history of colorectal cancer can make risk assessment easier and facilitate both collaborative studies and patient triage into appropriate screening programs.Reprints are not available.Read at the meeting of The American Society of Colon and Rectal Surgeons, Dallas, Texas, May 8 to 13, 2004.     

Results of screening first-degree relatives of patients with colorectal cancer: a community practice perspective.

Targeted screening by colonoscopy of asymptomatic first-degree relatives of patients with colorectal cancer (CRC) is promoted as a preventive health activity. This retrospective case control series details the results of this activity in a community-based referral gastroenterology practice. One advanced carcinoma and 22 adenomas in 15 patients were found in 118 individuals screened. Six per cent of those screened had advanced lesions (carcinoma, tubulovillous adenomas or adenomas larger than 1 cm). Colonoscopic screening of asymptomatic first-degree relatives of patients with CRC yields a limited number of clinically significant colonic neoplasms in this practice setting. Further cost-benefit data are needed.     

Colonic Neoplasia in Asymptomatic Persons with Negative Fecal Occult Blood Tests: Influence of Age, Gender, and Family History

Six hundred twenty-one asymptomatic persons with negative fecal occult blood tests (ages 50–75 yr), including 496 with no known risk factors for colorectal cancer and 125 with a single first-degree relative with a history of colonic neoplasia developed after age 40, underwent screening colonoscopy. Three Dukes A cancers were detected in average-risk persons. The overall prevalence of adenomatous polyps was 27%. Multiple logistic regression analysis revealed that increasing age and male gender were both strong predictors of colonic neoplasia ( p < 0.001). A positive family history of a single first-degree relative with colorectal cancer was not associated with an increased prevalence of colonic neoplasia ( p = 0.29), although an effect may be present if the relative was <60 yr at diagnosis. Overall 16% of males and 7% of women > 60 yr had at least one adenoma that was large (>1 cm in size), villous or tubulovillous, or had grade 3 dysplasia. We conclude that the prevalence of colonic neoplasia in asymptomatic persons with negative fecal occult blood tests is substantial, particularly in elderly males. A family history of a single first-degree relative diagnosed at age >60 yr with colorectal cancer is not associated with an increased prevalence of colonic adenomas.     

Potential effect of cyclooxygenase-2-specific inhibitors on the prevention of colorectal cancer: a cost-effectiveness analysis

PURPOSE: To estimate the potential cost-effectiveness of colorectal cancer chemoprevention with cyclooxygenase-2-specific inhibitors (COX-2 inhibitors). METHODS: Using a decision analytic Markov model, we estimated the discounted cost per life-year saved for three strategies: a COX-2 inhibitor alone; as an adjunct to colonoscopy every 10 years in persons at average risk of colorectal cancer; and as an adjunct to colonoscopy every 5 years in persons with first-degree relatives who had colorectal cancer. RESULTS: In the base case, the incremental cost per life-year saved with a COX-2 inhibitor alone compared with no screening was 233,300 dollars in persons at average risk of colorectal cancer and 56,700 dollars in persons with 2 first-degree relatives who had the disease. Chemoprevention was both less effective and more costly than screening. The incremental cost per life-year saved with a COX-2 inhibitor as an adjunct to screening was 823,800 dollars in persons at average risk and 404,700 dollars in persons with 2 first-degree relatives who had colorectal cancer. Combining a COX-2 inhibitor with less frequent screening was not as cost-effective as screening at currently recommended intervals. Cost-effectiveness estimates were highly sensitive to the cost of COX-2 inhibitors and their effect on the risk of cancer. CONCLUSION: Chemoprevention of colorectal cancer with COX-2 inhibitors is likely to incur substantially higher costs per life-year saved than are currently recommended screening strategies. COX-2 inhibitor use as an adjunct to screening may increase life expectancy, although at prohibitive costs, and is unlikely to result in less frequent screening.     

Variables associated with the risk of colorectal adenomas in asymptomatic patients with a family history of colorectal cancer.

The results of screening individuals referred to the Family Cancer Clinic at St Mark's Hospital from 1986 are presented. Colonoscopy was performed in 644 asymptomatic individuals (from 436 families) with a family history of colorectal cancer. Sixty nine (15.8%) of the families fulfilled the Amsterdam criteria for the hereditary non-polyposis colorectal cancer syndromes (HNPCC). Seven cases of colorectal cancer were diagnosed at an average age of 49 years; six at Dukes's stage A and one at stage C, four in subjects from Amsterdam criteria families. One hundred and forty four (22.4%) subjects had one or more adenomas. The prevalence of adenomas in the subjects from Amsterdam criteria families was 34 of 127 (26.8%) compared with 110 of 517 (21.3%) in those from other families; the age and sex adjusted odds ratio (OR) was 1.76 (p = 0.02). Factors influencing the prevalence of adenomas in screened individuals were evaluated. Multivariate analysis showed that independent variables significantly related to the risk of adenomas were: age (p < 0.0001), sex (p = 0.0002), and the number of generations (> or = 2 v 1) of relatives affected by either colorectal cancer or adenomas (p = 0.0006). The latter variable was more highly predictive of the probability of finding an adenoma at colonoscopy than a family history of two generations with cancer only (p = 0.056). The OR of having colorectal adenomas increased with age, by about twofold for each decade, and was twice as high in men than women, and in subjects with two or more generations relative to those with one generation affected by colorectal cancer or adenomas. Six of seven patients with cancer and 46 of 144 (31.9%) with adenomas had lesions proximal to the splenic flexure only. The proportion of individuals with proximal adenomas only was 47.1% in Amsterdam criteria families and 27.3% in the others (p=0.03). These findings support the view that colonoscopy rather than sigmoidoscopy is the method of choice for screening high risk groups.     

Colonic Neoplasms in Asymptomatic First-Degree Relatives of Colon Cancer Patients

First-degree relatives of colon cancer patients are at elevated risk for developing colorectal neoplasms. In order to assess the potential usefulness of screening by colonoscopy in this high-risk population, we reviewed the records of 48 colonoscopies performed on asymptomatic patients who were self- or physician-referred for colonoscopy because of a history of one or more first-degree relatives with colon cancer. Twelve (25%) had at least one adenomatous polyp, but no significant atypia was detected. No cancers were detected. One third of the lesions were beyond the reach of a flexible sigmoidoscope. This apparent increase in the prevalence of adenomas was most striking (46%) among men over the age of 50. These preliminary results demonstrate that colonoscopy is effective in detecting and removing adenomatous polyps in a substantial fraction of asymptomatic patients whose sole risk-factor is being a first-degree relative of a patient with colon cancer. Further studies in larger populations are warranted to determine the use of colonoscopy in screening these high-risk individuals.     

Risk of colorectal adenomas in patients with a family history of colorectal cancer: some implications for screening programmes.

BACKGROUND AND AIMS: Most colorectal cancers (CRC) arise in colorectal adenomas. A case-control study was conducted to see whether a family history of CRC is associated with a higher prevalence of colorectal adenomas. SUBJECTS: Subjects were drawn from all patients who underwent colonoscopy at the Royal Brisbane Hospital between 1980-1982 and 1985, and included 141 cases with colorectal adenomas diagnosed at colonoscopy and 882 controls who were free of polyps at colonoscopy. METHODS: The prevalence of family history of CRC was compared between patients with adenomas and negative colonoscopy controls. RESULTS: Overall, patients with one first degree relative with CRC were at no greater risk for adenomas at colonoscopy than patients with no family history (odds ratio (OR) = 0.8, 95% confidence intervals (CI) = 0.4, 1.5). Patients with two or more affected first degree relatives had a more than doubled risk for adenomas (OR = 2.3, 95% CI = 0.5, 8.2), and were also more likely to carry moderately or severely dysplastic adenomas (OR = 14.1, 95% CI = 2.0, 62.9). CONCLUSIONS: These findings are consistent with the hypothesis that some families, in addition to those with familial adenomatous polyposis, have an increased susceptibility to develop colorectal adenomas, and that adenomas in such families may have a greater tendency to undergo malignant transformation.     

Screening for colorectal carcinoma in cancer family syndrome kindreds

Screening for colorectal carcinoma (CRC) was organized for 236 asymptomatic family members in 22 Finnish cancer family syndrome (CFS) kindreds, and 58% (137) of the subjects accepted the invitation. Double-contrast colonography and sigmoidoscopy or colonoscopy were used. In 137 subjects aged 20-65 years, with 3 or more first-degree relatives with CRC, one screening visit showed a colonic neoplasm in 12 (9%) subjects. Two had carcinoma (Dukes A and B), and 10 subjects one or more adenomas. Two of the subjects not attending screening (2%) developed Dukes C colon carcinoma during the study period, and one of them died of cancer. Continued screening of 34 patients with a previously identified CFS showed metachronous colorectal tumours in 12 (35%) cases: 9 operable carcinomas and 9 adenomas within 3 years. The preliminary result of screening on the basis of CFS was encouraging. Effective and continuous screening, however, requires centralized organization. The continued follow-up of identified CFS cases effectively revealed metachronous colorectal tumours at a curable stage, but its benefit was burdened by a high rate of advanced malignancies other than CRC.