The role of heredity in the etiology of large bowel cancer: data from the Melbourne Colorectal Cancer Study

Familial colorectal cancer

The introduction of average-risk colorectal cancer (CRC) screening programs means that many subjects with family history of CRC and without well-described inherited syndromes can benefit from these public health policies. Therefore, the definition of which individuals should be named under the umbrella of the term "familial CRC" should be reconsidered to include only those who are outside of the protection of population-based screening and need to be moved towards a more intensive surveillance strategy. Two subgroups have been reported as having a high enough CRC risk to be included within the term "familial risk of CRC": individuals who have ≥1 first degree relative (FDR) with CRC diagnosed at age <50 years, and those who have ≥2 FDRs with CRC. Colonoscopy-based screening starting at age 40 years is proposed as the most accepted recommendation for these individuals. Finally, the evolution of Lynch syndrome screening from clinical criteria to tumor tissue analysis and new tools for screening pathogenic gene mutations associated with cancer susceptibility in individuals with early-onset CRC might help to reduce misclassification of familial CRC.

Effects of Family History on Relative and Absolute Risks for Colorectal Cancer: A Systematic Review and Meta-Analysis

BACKGROUND & AIMS

Guidelines recommend that individuals with familial colorectal cancer undergo colonoscopy surveillance instead of average-risk screening. However, these recommendations vary widely. To substantiate appropriate surveillance strategies, precise and valid evidence-based risk estimates are needed for individuals with a family history of colorectal cancer (CRC).

METHODS

We systematically searched MEDLINE, EMBASE, and Cochrane from inception to July 2018 for case-control and cohort studies investigating the effect of family history on CRC risk. We calculated summary estimates of pooled relative risks (RRs) using a random-effects model. Life tables were created to convert RR estimates into absolute risk estimates.

RESULTS

We screened 4417 articles and identified 42 eligible case-control and 20 cohort studies. In case-control studies, the RR for CRC in patients with 1 first-degree relative (FDR with CRC) was 1.92 (95% CI, 1.53-2.41) and 1.37 (95% CI, 0.76-2.46) for cohort studies. For individuals with 2 or more FDRs with CRC, the RR was 2.81 in case-control studies (95% CI, 1.73-4.55) and 2.40 in cohort studies (95% CI, 1.76-3.28). For individuals having a FDR diagnosed with CRC at an age younger than 50 years, the RR for CRC in their FDRs was 3.57 in case-control studies (95% CI, 1.07-11.85) and 3.26 in cohort studies (95% CI, 2.82-3.77). The cumulative absolute risks for CRC at 85 years in Western Europe were 4.8% for persons with 1 FDR with CRC (95% CI, 2.7%-8.3%), 8.2% for individuals with 2 or more FDRs (95% CI, 6.1%-10.9%), and 11% for persons with a FDR diagnosed with CRC at an age younger than 50 years (95% CI, 9.5%-12.4%).

CONCLUSIONS

In this systematic review and meta-analysis, we found that the RR of CRC among FDRs is lower than previously expected, especially based on cohort studies. Risk estimates are affected by the number of relatives with CRC and their age at diagnosis. Intensified colonoscopy surveillance strategies could be considered for high-risk groups. PROSPERO trial identification no: CRD42018103058.

Lower Relative Contribution of Positive Family History to Colorectal Cancer Risk with Increasing Age: A Systematic Review and Meta-Analysis of 9.28 Million Individuals

OBJECTIVES

Existing algorithms predicting the risk of colorectal cancer (CRC) assign a fixed score for family history of CRC. Whether the increased CRC risk attributed to family history of CRC was higher in younger patients remains inconclusive. We examined the risk of CRC associated with family history of CRC in first-degree relative (FDR) according to the age of index subjects (<40 vs. ≥40; <50 vs. ≥50; and <60 vs. ≥60 years).

METHODS

Ovid Medline, EMBASE, and gray literature from the reference lists of all identified studies were searched from their inception to March 2017. We included case-control/cohort studies that investigated the relationship between family history of CRC in FDR and prevalence of CRC. Two reviewers independently selected articles according to the PRISMA guideline. A random effects meta-analysis pooled relative risks (RR).

RESULTS

We analyzed 9.28 million subjects from 63 studies. A family history of CRC in FDR confers a higher risk of CRC (RR = 1.76, 95% CI = 1.57-1.97, p < 0.001). This increased risk was higher in younger individuals (RR = 3.29, 95% CI = 1.67-6.49 for <40 years versus RR = 1.42, 95% CI = 1.24-1.62 for ≥40 years, p = 0.017; RR = 2.81, 95% CI = 1.94-4.07 for <50 years versus RR = 1.47, 95% CI = 1.28-1.69 for ≥50 years, p = 0.001). No publication bias was identified, and the findings are robust in subgroup analyses.

CONCLUSIONS

The increase in relative risk of CRC attributed to family history was found to be higher in younger individuals. Family history of CRC could be assigned a higher score for younger subjects in CRC risk prediction algorithms. Future studies should examine if such approach may improve their predictive capability.

Genetic Epidemiology of Colorectal Cancer

Starting from a survey of the studies on familial aggregation of colorectal cancer, we introduce the aims of genetic epidemiology. One of its main goals is to assess population frequency of cancer susceptibility genes and to determine the age-specific risks for carriers with respect to non-carriers. In section two, segregation analysis investigations are reviewed, and inferences on the relevance of genetic components of susceptibility to colorectal cancer are drawn. In section three, the HNPCC paradigm is discussed in the light of the Knudson model of tumorigenesis and recent advances of molecular research. In the last section we show an example of genotype/environment interaction in the etiology of a particular cancer and present a conceptual framework for studies on cancer genetic epidemiology in terms of attributable and relative risk.

Do alcoholic beverages, obesity and other nutritional factors modify the risk of familial colorectal cancer? A systematic review

PURPOSE

Individuals with family history of colorectal cancer are at higher risk of colorectal cancer than the general population. Until now, guidelines for familial colorectal cancer risk have only pointed at early diagnosis efforts via screening tests and surveillance, and payed scarce or no attention to lowering exposure to modifiable risk factors, notably nutritional factors.

METHODS

We conducted a systematic review of epidemiological studies investigating the associations between nutritional factors, family history of colorectal cancer, and colorectal cancer risk. From the 5312 abstracts identified until December 2016, 184 full text articles were examined for eligibility. Finally, 31 articles (21 from case-control studies, 9 from cohort studies and 1 from an intervention study) met inclusion criteria and were analyzed.

RESULTS

Mainly, the combinations of family history of colorectal cancer and higher consumptions of alcoholic beverages, red or processed meat, or overweight/obesity increase the risk of colorectal cancer. Consistently, a strong increase is observed with the combinations of family history of colorectal cancer and unhealthy dietary patterns/lifestyles. Statistically significant interactions between these nutritional factors, family history of colorectal cancer and colorectal cancer risk are reported. Other data are inconclusive and additional prospective studies are needed.

CONCLUSIONS

For the first time, our findings highlight that addressing high consumption of alcoholic beverages, red or processed meat, and overweight/obesity, and more largely the exposure to multiple unhealthy dietary/nutritional behaviors could offer new perspectives of prevention to individuals with family history of colorectal cancer. A better information of these patients and of health professionals on these nutritional modifiable risk factors is recommended.

Prospective study of alcohol consumption and the risk of colorectal cancer before and after folic acid fortification in the United States

PURPOSE

To evaluate the influence of alcohol consumption on the risk of colorectal cancer according to folic acid fortification period in the United States.

METHODS

We evaluated the association between alcohol consumption and colorectal cancer by fortification period (before 1998 vs. after 1998) in 2 prospective cohort studies, the Nurses' Health Study (NHS) of women and the Health Professionals Follow-up Study (HPFS) of men, in which 2793 cases of invasive colorectal cancer were documented.

RESULTS

Alcohol consumption was associated with an increased risk of colorectal cancer. Among nonusers of multivitamins and/or folic acid supplements, the pooled multivariate relative risk for ≥30 g/d drinkers versus nondrinkers was 1.36 (95% confidence interval [95% CI], 1.09-1.70; P for trend, 0.02). The effect of alcohol consumption was slightly stronger in the prefolic acid fortification period (1980 NHS/1986 HPFS-1998) than in the postfortification period (1998-2008); the pooled multivariate relative risks for ≥30 g/d drinkers versus nondrinkers were 1.31 (95% CI, 1.00-1.71; P for trend, 0.10) in the prefortification period and 1.07 (95% CI, 0.69-1.65; P for trend, 0.67) in the postfortification period.

CONCLUSIONS

Folic acid fortification may attenuate the adverse effect of high alcohol consumption on the risk of colorectal cancer.

Meta-analyses of colorectal cancer risk factors

PURPOSE

Demographic, behavioral, and environmental factors have been associated with increased risk of colorectal cancer (CRC). We reviewed the published evidence and explored associations between risk factors and CRC incidence.

METHODS

We identified 12 established non-screening CRC risk factors and performed a comprehensive review and meta-analyses to quantify each factor's impact on CRC risk. We used random-effects models of the logarithms of risks across studies: inverse-variance weighted averages for dichotomous factors and generalized least squares for dose-response for multi-level factors.

RESULTS

Significant risk factors include inflammatory bowel disease (RR = 2.93, 95 % CI 1.79-4.81); CRC history in first-degree relative (RR = 1.80, 95 % CI 1.61-2.02); body mass index (BMI) to overall population (RR = 1.10 per 8 kg/m(2) increase, 95 % CI 1.08-1.12); physical activity (RR = 0.88, 95 % CI 0.86-0.91 for 2 standard deviations increased physical activity score); cigarette smoking (RR = 1.06, 95 % CI 1.03-1.08 for 5 pack-years); and consumption of red meat (RR = 1.13, 95 % CI 1.09-1.16 for 5 servings/week), fruit (RR = 0.85, 95 % CI 0.75-0.96 for 3 servings/day), and vegetables (RR = 0.86, 95 % CI 0.78-0.94 for 5 servings/day).

CONCLUSIONS

We developed a comprehensive risk modeling strategy that incorporates multiple effects to predict an individual's risk of developing CRC. Inflammatory bowel disease and history of CRC in first-degree relatives are associated with much higher risk of CRC. Increased BMI, red meat intake, cigarette smoking, low physical activity, low vegetable consumption, and low fruit consumption were associated with moderately increased risk of CRC.

Alcohol consumption and the risk of colon cancer by family history of colorectal cancer

BACKGROUND

Individuals with a family history of colorectal cancer may be more susceptible to adverse effects of alcohol consumption.

OBJECTIVE

We investigated whether the association between alcohol consumption and colon cancer risk differed by family history of colorectal cancer.

DESIGN

We conducted prospective studies in women and men in the Nurses' Health Study and Health Professionals Follow-Up Study, respectively. Alcohol consumption was first assessed in 1980 in women and in 1986 in men.

RESULTS

During a follow-up of 26 y among 87,861 women and 20 y among 47,290 men, we documented 1801 cases of colon cancer (1094 women and 707 men). Higher alcohol consumption was associated with an elevated risk of colon cancer, although the association was significant only for the highest intake category of ≥30 g/d, with no significant linear trend. The association between alcohol consumption and colon cancer risk differed by family history of colorectal cancer; in comparison with nondrinkers, the pooled multivariate RRs for alcohol consumption of ≥30 g/d were 1.23 (95% CI: 0.96, 1.57; NS) among those with no family history and 2.02 (95% CI: 1.30, 3.13) among those with a family history of colorectal cancer (P value test for difference = 0.05). In comparison with nondrinkers with no family history, the RR for colon cancer was 2.80 (95% CI: 2.00, 3.91) for individuals who consumed ≥30 g/d and who had a family history of colorectal cancer.

CONCLUSION

Reducing alcohol consumption may decrease the incidence of colon cancer, especially among those with a family history of colorectal cancer.

The association of tumor microsatellite instability phenotype with family history of colorectal cancer

Family history is a strong predictor of colorectal cancer risk; however, a diagnosis of colorectal cancer among first-degree relatives has not been systematically investigated as a function of the colorectal cancer molecular subtypes related to tumor microsatellite instability (MSI) status. We investigated whether the observable familial colorectal cancer risks differed according to tumor MSI subtypes, stratified as MSI-High (>30% instability), MSI-Low (<30% instability), and MSS (no instability). Data from 3,143 population-based colorectal cancer cases from five institutions were assessed for family history according to the Amsterdam criteria and the Bethesda guidelines, age at diagnosis, sex, tumor location, and MSI status. The distribution of patient characteristics by MSI status was compared using polytomous logistic regression. Overall, 2.8% colorectal cancer cases met the Amsterdam criteria and 37% met the Bethesda guidelines. There were 14% MSI-High, 13% MSI-Low, and 73% MSS colorectal cancers. MSI-High (P<0.0001) and MSI-Low tumors (P=0.01) were more proximally located than MSS tumors. MSI-High tumors were more common among females (P<0.001). The highest proportion of MSI-High tumors occurred in cases<40 years of age whereas the age-dependent distribution of MSI-Low tumors was unchanged. MSI-High tumors showed a statistically significant association with increasing numbers of first-degree relatives with colorectal cancer (P=0.002); this association disappeared, however, when MSI-High cases meeting Amsterdam criteria were removed from the analysis. MSI-Low tumors did not show a similar association with family history of colorectal cancer. Familial risk associated with MSI-High tumors is primarily driven by the Amsterdam-criteria patients. MSI-Low tumors may represent a distinct subtype of colorectal cancer with respect to certain epidemiologic variables studied here.

Family history and age at initiation of colorectal cancer screening

OBJECTIVES

To review and combine the best available epidemiological evidence, by sex and age, that may help decision and policy makers form recommendations as to how much earlier colorectal cancer (CRC) screening should be initiated among people with a family history of CRC than among average-risk people.

PATIENTS AND METHODS

Combining population-based cancer registry and health interview survey data from the United States and results of a recent meta-analysis of epidemiological studies, we estimated cumulative incidence of CRC within subsequent 10 yr (CI(10)) at various ages among men and women with and without a family history of CRC. We estimated both the CI(10) levels reached in average-risk 45-, 50-, 55-, and 60-yr-old men and women and the age at which the same CI(10) levels are reached in men and women with a history of CRC in a first-degree relative.

RESULTS

Despite major differences in CRC risk by sex, and despite the strong age gradient in relative risk associated with a positive family history, "risk advancement periods" for those with a family history were consistently found to be between 9 and 11 yr for both sexes and at all four ages assessed.

CONCLUSION

Advancement of first CRC screening by 10 yr among both men and women with a family history of CRC compared to the average-risk population (e.g., from 50 to 40 yr of age) appears to be a reasonable, evidence-based recommendation.

Design considerations in a sib-pair study of linkage for susceptibility loci in cancer

BACKGROUND

Modern approaches to identifying new genes associated with disease allow very fine analysis of association and can be performed in population based case-control studies. However, the sibpair design is still valuable because it requires few assumptions other than acceptably high penetrance to identify genetic loci.

METHODS

We conducted simulation studies to assess the impact of design factors on relative efficiency for a linkage study of colorectal cancer. We considered two test statistics, one comparing the mean IBD probability in affected pairs to its null value of 0.5, and one comparing the mean IBD probabilities between affected and discordant pairs. We varied numbers of parents available, numbers of affected and unaffected siblings, reconstructing the genotype of an unavailable affected sibling by a spouse and offspring, and elimination of sibships where the proband carries a mutation at another locus.

RESULTS

Power and efficiency were most affected by the number of affected sibs, the number of sib pairs genotyped, and the risk attributable to linked and unlinked loci. Genotyping unaffected siblings added little power for low penetrance models, but improved validity of tests when there was genetic heterogeneity and for multipoint testing. The efficiency of the concordant-only test was nearly always better than the concordant-discordant test. Replacement of an unavailable affected sibling by a spouse and offspring recovered some linkage information, particularly if several offspring were available. In multipoint analysis, the concordant-only test was showed a small anticonservative bias at 5 cM, while the multipoint concordant-discordant test was generally the most powerful test, and was not biased away from the null at 5 cM.

CONCLUSION

Genotyping parents and unaffected siblings is useful for detecting genotyping errors and if allele frequencies are uncertain. If adequate allele frequency data are available, we suggest a single-point affecteds-only analysis for an initial scan, followed by a multipoint analysis of affected and unaffected members of all available sibships with additional markers around initial hits.

Differential effects of wine consumption on colorectal cancer outcomes based on family history of the disease

Potentially favorable effects of wine consumption on colorectal cancer (CRC) incidence have been reported, but effects on clinical outcomes are unknown. This case-only analysis was designed to investigate outcomes among familial (n = 141) and sporadic (n = 358) CRC patients enrolled in the University of California Irvine CRC gene-environment study during 1994-1996 based on their reported frequency of wine consumption in the year prior to diagnosis. Cases were categorized as either regular or infrequent wine consumers. Univariate survival rate analyses were estimated using the Kaplan and Meier method and log-rank test. Multivariate survival analyses were performed using Cox proportional hazards ratios (HRs). Earlier stage at presentation (P = 0.034) was noted for familial (but not sporadic) CRC cases reporting regular wine consumption. An overall survival (OS) benefit was observed for familial (but not sporadic) CRC cases that were regular (10-yr OS = 75%) versus infrequent wine consumers (10-yr OS = 47%; P = 0.002). This survival improvement for familial CRC cases remained after adjustment for age, stage, treatment, and other clinically relevant factors (HR = 0.50, 95% confidence interval = 0.25-0.99). Our findings implicate favorable effects of wine consumption on stage at presentation and survival in CRC, selectively among familial CRC cases.

A familial component to human rectal cancer, independent of colon cancer risk

BACKGROUND & AIMS

The Utah Population Database (UPDB) is unique; it links genealogy for over 2 million Utah individuals to a statewide Cancer Registry. We have investigated the familial nature of rectal cancer, considered independently from colon cancer.

METHODS

We estimated relative risks in relatives, and average relatedness among rectal cancer patients using matched controls from the UPDB.

RESULTS

There is a significant increased risk for rectal cancer in first-degree relatives of rectal cancer patients (relative risk [RR], 1.97), equivalent to the risk for colon cancer (RR, 2.11). The significant increased risk for rectal cancer extends to second- and third-degree relatives. The RR for rectal cancer among first-degree relatives of young-onset rectal cancer patients (<55 y), is equivalent (RR, 3.34) to their risk of colon cancer (RR, 3.35).

CONCLUSIONS

The UPDB provides strong evidence for a familial component to rectal cancer that may include a genetic component in addition to shared environment. There is a significant increased risk of rectal cancer in the close and distant relatives of rectal cancer patients, which is even higher among relatives of young-onset patients. Although it has been reported that relatives of colon cancer probands are at increased risk for colorectal cancer, the risk of large-bowel cancer among relatives of rectal cancer patients has been less clear. Relatives of rectal cancer probands experience a risk of cancer of the large bowel that is at least as high as the risk previously reported for relatives of individuals with colon cancer.

Estimating the referral rate for cancer genetic assessment from a systematic review of the evidence

To estimate the optimal proportion of new patients diagnosed with cancer who require assessment and evaluation for familial cancer genetic risk, based on the best evidence available. We identified evidence of the patients who require assessment for familial genetic risk when diagnosed with cancer through extensive literature reviews and searches of guidelines. Epidemiological data on the distribution of cancer type, presence of a family history, age and other factors that influence referral for genetic assessment were identified. Decision trees were constructed to merge the evidence-based recommendations with the epidemiological data to calculate the optimal proportion of patients who should be referred. We identified 'high probability' and 'moderate probability' groups for having a genetic susceptibility. The proportion of patients diagnosed with cancer in Australia who have a high probability of having a genetic predisposition and who should be referred for genetic assessment is 1%. If the moderate probability group is also assessed this proportion increases to 6%. This model has identified the proportion of new patients diagnosed with cancer who should be referred for genetic assessment. This data is the first step in determining the resources required for provision of an adequate cancer genetic service.

Colorectal cancer protective effects and the dietary micronutrients folate, methionine, vitamins B6, B12, C, E, selenium, and lycopene

The data reported here were obtained from the case-control arm of a large, comprehensive, population-based investigation of colorectal cancer incidence, etiology, and survival, the Melbourne Colorectal Cancer Study, conducted in Melbourne, Australia. This part of the case-control study was designed to identify dietary factors associated with colorectal cancer risk in 715 incident cases compared with 727 age/sex frequency-matched randomly chosen community controls, in which a quantitative assessment of all foods eaten was made. New data are presented on the potential of two groups of micronutrients as protective agents, namely, those involved in DNA methylation, synthesis, and repair (folate, methionine, and vitamins B6 and B12) and those with antioxidant properties (selenium, vitamins E and C, and lycopene). The adjusted odds ratios showed that for folate there was significant protection for rectal cancer in second and third quintiles of consumption but not for colon cancer, and this was similar for methionine consumption. Vitamin B6 consumption was significantly protective for both colon and rectal cancer at the higher quintiles, and this was similar for vitamin B12. Dietary selenium was significantly protective at middle quintiles of consumption at both cancer sites. Dietary vitamins E and C were statistically significantly protective for both colon and rectal cancer at all levels of consumption, and for both vitamins there was a dose-response effect of increasing protection, particularly so for colon cancer. Lycopene was not associated with colorectal cancer risk. A combined model included vitamins E, C, and B12 and selenium as micronutrients protective for colorectal cancer and folate, which, however, showed an increased risk at the highest level of consumption. These data support the proposition that a diet containing the dietary micronutrients involved in DNA methylation (folate, methionine, and vitamins B6 and B12) and some of those with antioxidant properties (selenium and vitamins E and C) may have a role to play in lowering colorectal cancer risk and also that such protection can be achieved by dietary means alone.

Measures of familial aggregation depend on definition of family history: meta-analysis for colorectal cancer

OBJECTIVE

Familial aggregation, a primary theme in genetic epidemiology, can be estimated from family studies based on an index person. The excess risk due to the presence of affected family members can be classified according to whether disease in the relatives is considered a risk factor for the index person (type I relative risk) or whether the disease status of the index person is considered a risk factor for the relatives (type II relative risk).

STUDY DESIGN AND SETTING

A meta-analysis of published colorectal cancer studies reporting a measure of familial association was performed and application of multilevel linear regression to model age-specific relative risks presented.

RESULTS

The pooled type I relative risk of colorectal cancer given any affected first-degree relative (based on 20 studies) was 2.26 (95% confidence interval CI = 1.86, 2.73) and decreased with the age of the consultand. The pooled type II estimate (based on seven studies) was 2.81 (95% CI = 2.05, 3.85).

CONCLUSION

Type I relative risks are useful in clinical counseling settings when a consultand wants to know his/her disease risk given his or her family history. Type II relative risks can be used to quantify the risk of disease to relatives of an affected individual and then identify subjects eligible for screening.

Relative and absolute risk of colorectal cancer for individuals with a family history: A meta-analysis

Accurate risk estimates for individuals with a family history of colorectal cancer are important for surveillance strategies. We systematically reviewed the literature on familial risks of colorectal cancer to determine relative risk estimates for categories of family history and translated these relative risk estimates into absolute risk estimates. A random-effects meta-analysis pooled the effect estimates from individual studies and actuarial life-table methods converted relative into absolute risks. Fifty-nine studies were identified including 47 that estimated the relative risk of developing colorectal cancer given at least one affected first-degree relative. The pooled risk estimate was 2.24 (95% CI 2.06 to 2.43) which rose to 3.97 (95% CI 2.60 to 6.06) with at least two affected relatives. A population lifetime risk of 1.8% for a 50-year old increased to 3.4% (95% CI 2.8 to 4.0) with at least one affected relative or 6.9% (95% CI 4.5 to 10.4) with two or more. Accurate absolute risk estimates show how cancer risks vary over time, particularly by pattern of family history and age of individual at-risk.

Family history and colorectal cancer screening: a survey of physician knowledge and practice patterns

OBJECTIVES

Risk stratification is essential to effective implementation of colorectal cancer (CRC) screening strategies. The objectives of this study were to assess and compare the current knowledge and practice patterns of gastroenterologists and primary care physicians regarding familial risk of CRC.

METHODS

We conducted a survey of regional gastroenterologists and a sample of university- and community-based primary care physicians. The survey instrument assessed physician knowledge of screening recommendations and current practices for individuals with family histories of CRC, adenomatous polyps (APs), familial adenomatous polyposis (FAP), and hereditary nonpolyposis cancer (HNPCC). The instrument also elicited data about familial risk assessment, documentation, and notification of at-risk family members.

RESULTS

Thirty-five gastroenterologists (65%) and 58 primary care physicians (92%) completed the survey. Most gastroenterologists and primary care physicians (85% vs 72%) chose age 40 as the appropriate age to begin screening for a family history of CRC, but relatively few (37% vs 36%) recommended screening at age 40 for a family history of APs. Gastroenterologists were significantly more likely to recommend screening for FAP at puberty (80% vs 27%, p < 0.001) and for HNPCC at age 25 (73% vs 50%, p = 0.04). Colonoscopy was the preferred screening strategy by both groups for family histories of CRC (97%), HNPCC (97%), and APs (77%); primary care physicians also preferred colonoscopy for family histories of CRC (72%) and HNPCC (76%) but flexible sigmoidoscopy plus fecal occult blood testing for a family history of APs (38%). Gastroenterologists were more likely to recommend genetic testing for persons at risk of FAP (91% vs 71%, p = 0.03) and HNPCC (72% vs 57%, p = 0.18), routinely inquire about a family history of CRC or APs (93% vs 63%, p < 0.001), and recommend notification of at-risk first-degree relatives with family histories of CRC (94% vs 55%, p < 0.001) or AP (53% v.s 6%, p < 0.001).

CONCLUSION

Although gastroenterologists are more likely than primary care physicians to elicit a family history of colorectal neoplasia and implement appropriate screening strategies, overall compliance with recommended guidelines and notification of at-risk relatives are suboptimal. Novel approaches for improving awareness of the available screening guidelines are needed.

Features of colorectal cancers with high-level microsatellite instability occurring in familial and sporadic settings: parallel pathways of tumorigenesis

High-level microsatellite instability (MSI-H) is demonstrated in 10 to 15% of sporadic colorectal cancers and in most cancers presenting in the inherited condition hereditary nonpolyposis colorectal cancer (HNPCC). Distinction between these categories of MSI-H cancer is of clinical importance and the aim of this study was to assess clinical, pathological, and molecular features that might be discriminatory. One hundred and twelve MSI-H colorectal cancers from families fulfilling the Bethesda criteria were compared with 57 sporadic MSI-H colorectal cancers. HNPCC cancers presented at a lower age (P < 0.001) with no sporadic MSI-H cancer being diagnosed before the age of 57 years. MSI was less extensive in HNPCC cancers with 72% microsatellite markers showing band shifts compared with 87% in sporadic tumors (P < 0.001). Absent immunostaining for hMSH2 was only found in HNPCC tumors. Methylation of hMLH1 was observed in 87% of sporadic cancers but also in 55% of HNPCC tumors that showed loss of expression of hMLH1 (P = 0.02). HNPCC cancers were more frequently characterized by aberrant beta-catenin immunostaining as evidenced by nuclear positivity (P < 0.001). Aberrant p53 immunostaining was infrequent in both groups. There were no differences with respect to 5q loss of heterozygosity or codon 12 K-ras mutation, which were infrequent in both groups. Sporadic MSI-H cancers were more frequently heterogeneous (P < 0.001), poorly differentiated (P = 0.02), mucinous (P = 0.02), and proximally located (P = 0.04) than HNPCC tumors. In sporadic MSI-H cancers, contiguous adenomas were likely to be serrated whereas traditional adenomas were dominant in HNPCC. Lymphocytic infiltration was more pronounced in HNPCC but the results did not reach statistical significance. Overall, HNPCC cancers were more like common colorectal cancer in terms of morphology and expression of beta-catenin whereas sporadic MSI-H cancers displayed features consistent with a different morphogenesis. No individual feature was discriminatory for all HNPCC cancers. However, a model based on four features was able to classify 94.5% of tumors as sporadic or HNPCC. The finding of multiple differences between sporadic and familial MSI-H colorectal cancer with respect to both genotype and phenotype is consistent with tumorigenesis through parallel evolutionary pathways and emphasizes the importance of studying the two groups separately.

A systematic review and meta-analysis of familial colorectal cancer risk

OBJECTIVE

The aim of this study was to identify published studies quantifying familial colorectal cancer (CRC) risks in first-degree relatives of CRC and colorectal adenoma (CRA) cases and, through a meta-analysis, obtain more precise estimates of familial risk according to the nature of the family history and type of neoplasm.

METHODS

Twenty-seven case-control and cohort studies were identified, which reported risks of CRC in relatives of CRC cases and nine, which reported the risk of CRC in relatives of CRA cases. Pooled estimates of risk for various categories of family history were obtained by calculating the weighted average of the log relative risk estimates from studies.

RESULTS

The pooled estimates of relative risk were as follows: a first-degree relative with CRC 2.25 (95% CI = 2.00-2.53), colon 2.42 (95% CI = 2.20-2.65), and rectal 1.89 (95% CI = 1.62-2.21) cancer; parent with CRC 2.26 (95% CI = 1.87-2.72); sibling with CRC 2.57 (95% CI = 2.19-3.02); more than one relative with CRC 4.25 (95% CI = 3.01-6.08); relative diagnosed with CRC before age 45, 3.87 (95% CI = 2.40-6.22); and a relative with CRA 1.99 (95% CI = 1.55-2.55).

CONCLUSIONS

Individuals with a family history of CRC and CRA have a significantly elevated risk of developing CRC compared with those without such a history. Risks are greatest for relatives of patients diagnosed young, those with two or more affected relatives, and relatives of patients with colonic cancers.

Family history of colorectal adenomatous polyps as a risk factor for colorectal cancer

The aim of this study was to evaluate the risk of common colorectal cancer among first-degree relatives of patients with colorectal adenomatous polyps. In a population screening programme, 59406 subjects underwent an immunochemical faecal occult blood test. In a medical check-up-based cross-sectional study, 6139 subjects had a colonoscopic examination. They were divided into two groups, according to the results of a questionnaire on family history of colorectal adenomatous polyps, and the detection rates for colorectal cancer were compared in the groups positive or negative for a family history of colorectal adenomatous polyps. In the screening programme-based cross-sectional study, the detection rate for colorectal cancer was 0.57% (95% confidence interval (CI): 0.38-0.76) and 0.15% (95% CI: 0.12-0.18) in subjects with and without a family history of colorectal adenomatous polyps, respectively, showing a significant difference in the detection rate for colorectal cancer between the two groups (P<0.05). In the medical check-up-based cross-sectional study, the detection rate for colorectal cancer was 2.31% (95% CI: 1.15-3.47) and 0.53% (95% CI: 0. 34-0.72) in subjects with and without a family history of colorectal adenomatous polyps, respectively, indicating a significant difference between the two groups (P<0.05). These findings indicate that first-degree relatives of patients with colorectal adenomatous polyps have an elevated risk for common colorectal cancer, and that people with a family history of colorectal adenomatous polyps should be considered as a priority group for colorectal cancer screening.

Family history of cancer in children and young adults with colorectal cancer

BACKGROUND

Family history of colorectal cancer among adult patients has been reported in the literature. Although extremely rare in children, colorectal cancer in this population may represent a unique group in whom genetic factors play a significant etiologic role. The aim of the present study was to assess genetic contribution, as measured by family history, to the development of colorectal cancer in probands under 21 years of age at diagnosis.

PROCEDURE

Detailed family histories were obtained from surviving patients or their parents. The risk [standardized incidence ratio (SIR)] of cancer in the relatives was calculated by comparing the observed and the expected incidence based on rates in the general population and person-years at risk.

RESULTS

Twenty-five patients (median age at diagnosis 15 years) diagnosed with colorectal cancer at St. Jude Children's Research Center since 1964 or their surviving next of kin were available for interview. The 461 relatives contributed 18,908 person-years of follow-up. Statistically significant increased risk of colorectal cancer was present among all relatives (SIR = 6.0, 95% CI, 2.7-10.6), and the increased risk of colorectal cancer was confined to relatives of probands who were under 15 years of age at diagnosis (SIR = 10.0, 95% CI, 4.5-17.6). In addition, there was an excess of uterine/cervical cancer among all female relatives (SIR = 6.5, 95% CI, 3.2-10.9).

CONCLUSIONS

The observed excess of colorectal cancer, in relatives of younger probands, suggests the need to examine these kindreds for genetic instability resulting from defects in mismatch repair genes to characterize further the patterns of risk observed.

Screening and surveillance for colorectal carcinoma

Screening and surveillance examinations are effective in lowering colorectal cancer risk. Screening tests have been demonstrated to reduce colorectal cancer mortality. Colonoscopic removal of adenomatous polyps has been determined to reduce colorectal cancer incidence. High-risk individuals and their family members should be identified and offered more aggressive recommendations for appropriate screening and surveillance guidelines. Colorectal cancer screening strategies are in an acceptable range of cost effectiveness.

Risk factors for colorectal cancer in subjects with family history of the disease

The relationship between lifestyle factors, past medical conditions, daily meal frequency, diet and the risk of 'familial' colorectal cancer has been analysed using data from a case-control study conducted in northern Italy. A total of 1584 colorectal cancer patients and 2879 control subjects were admitted to a network of hospitals in the Greater Milan area and the Pordenone province. The subjects included for analysis were the 112 cases and the 108 control subjects who reported a family history of colorectal cancer in first-degree relatives. Colorectal cancer cases and control subjects with family history were similarly distributed according to sex, age, marital status, years of schooling and social class. Familial colorectal cancer was associated with meal frequency, medical history of diabetes (relative risk, RR = 4.6) and cholelithiasis (RR = 5.2). Significant positive trends of increasing risk with more frequent consumption were observed for pasta (RR = 2.5, for the highest vs the lowest intake tertile), pastries (RR = 2.4), red meat (RR = 2.9), canned meat (RR = 1.9), cheese (RR = 3.5) and butter (RR = 1.9). Significant inverse associations and trends in risk were observed for consumption of poultry (RR = 0.4), tomatoes (RR = 0.2), peppers (RR = 0.3) and lettuce (RR = 0.3). Significant inverse trends in risk with increasing consumption for beta-carotene and ascorbic acid were observed (RR = 0.5 and 0.4 respectively, highest vs lowest intake tertile). These results suggest that risk factors for subjects with a family history of colorectal cancer in first-degree relatives are not appreciably different from recognized risk factors of the disease in the general population.

Basis and consequences of primary and secondary prevention of gastrointestinal tumors

Carcinomas of the gastrointestinal tract (GI) are among the most common malignancies with regard to their incidence and mortality. Nutritional factors play an important role in the tumor development. The strength of their influence varies with the localization in the GI tract. Epidemiological studies focusing on GI cancer incidence or mortality as an endpoint necessitate large numbers of subjects to achieve significant results. Generally, a low energy and fat intake and a high intake of antioxidative vitamins (vitamin C, E, beta-carotene) and secondary plant metabolites (especially polyphenols) appear to be protective in GI carcinogenesis. Moderate drinking of alcohol and increased consumption of whole grain products, as opposed to highly refined carbohydrates, may help to reduce the risk of colon cancer. The recommended type of diet is low in fat, especially in saturated fatty acids, includes monounsaturated fatty acids, and includes moderate amounts of polyunsaturated fatty acids (no more than 10% of calories). Moderate consumption of salt and of highly salted, smoked, and barbecued foods should be encouraged. Obesity should be avoided by trying to match energy intake with expenditure while increasing physical activity levels. The mechanisms by which nutritional factors act especially on molecular events still remain to be examined. The use of molecular biomarkers will help us better understand cancer development as well as the role and significance of nutritional factors in this process.

A prospective study of family history and the risk of colorectal cancer

BACKGROUND

A family history of colorectal cancer is recognized as a risk factor for the disease. However, as a result of the retrospective design of prior studies, the strength of this association is uncertain, particularly as it is influenced by characteristics of the person at risk and the affected family members.

METHODS

We conducted a prospective study of 32,085 men and 87,031 women who had not previously been examined by colonoscopy or sigmoidoscopy and who provided data on first-degree relatives with colorectal cancer, diet, and other risk factors for the disease. During the follow-up period, colorectal cancer was diagnosed in 148 men and 315 women.

RESULTS

The age-adjusted relative risk of colorectal cancer for men and women with affected first-degree relatives, as compared with those without a family history of the disease, was 1.72 (95 percent confidence interval, 1.34 to 2.19). The relative risk among study participants with two or more affected first-degree relatives was 2.75 (95 percent confidence interval, 1.34 to 5.63). For participants under the age of 45 years who had one or more affected first-degree relatives, the relative risk was 5.37 (95 percent confidence interval, 1.98 to 14.6), and the risk decreased with increasing age (P for trend, < 0.001).

CONCLUSIONS

A family history of colorectal cancer is associated with an increased risk of the disease, especially among younger people.

Should relatives of patients with colorectal cancer be screened? A critical review of the literature

PURPOSE

The objective of our investigation was to attempt to address the controversial issue concerning index screening and surveillance of relatives of patients with colorectal cancer and to identify those areas of research that should be considered in future studies.

METHODS

Relevant literature was reviewed concerning the screening of asymptomatic first-degree relatives of patients with colorectal cancer not associated with the rare autosomal dominant inherited colorectal cancer syndromes.

RESULTS

The data reviewed suggest that there is an increased risk of colorectal neoplasia in this population and a significantly higher yield of adenomas and carcinomas when colonoscopy is used for index screening. However, significant variability in study design and screening protocols and inconsistencies in data presentation make clinical interpretation and data analysis confusing and difficult.

CONCLUSIONS

There is a critical need for standardization in future studies. Furthermore, as there are no studies that document decreased overall mortality from colorectal cancer in first-degree relatives as a result of screening, the decision as to whether to screen this population needs to be based on future prospective controlled trials.

Southwestern internal medicine conference: hereditary predisposition to colorectal cancer: new insights

Hereditary predisposition to colorectal cancer assumes two well-defined forms: familial adenomatous polyposis and hereditary nonpolyposis colon cancer. These tumors segregate as autosomal dominant conditions whose penetrance increases with age; cancer is expected to develop ultimately in as much as 50% of the offspring of affected individuals. These traits account for less than 1% and approximately 5% of all colorectal cancer, respectively. In addition, first-degree relatives of patients with common (sporadic) colorectal neoplasia are at increased risk of colorectal cancer. This relative risk averages approximately twofold but is significantly higher for relatives of younger patients (age at diagnosis, < 55 years). Familial adenomatous polyposis and a major subset of hereditary nonpolyposis colon cancer are due to loss-of-function germline mutations of genes located on chromosomes 5q and 2p, respectively. Both of these genes have been cloned recently. The gene affected in familial polyposis, APC, encodes a protein of unknown function that normally is found on the surface of maturing cells in the upper colonic crypts. The relevant gene in many hereditary nonpolyposis colon cancer kindreds is hMSH2. This gene encodes the human homologue of a bacterial protein MutS, which is part of a system known to repair base mismatches in newly replicated DNA. Loss of hMSH2 function may explain the strikingly erroneous replication of short DNA repeats (microsatellites) in colon tumors from patients with hereditary nonpolyposis colon cancer. Because this error-prone replication is found in approximately 13% of nonfamilial colon cancers, defective mismatch repair may contribute to the development of both hereditary and sporadic colon neoplasia. Molecular genetic assays to detect mutated alleles of these genes will facilitate presymptomatic identification of carriers in families with familial polyposis and hereditary nonpolyposis colon cancer. Current recommendations for surveillance of family members are presented in the light of the new genetic understanding of these diseases.

Current follow-up strategies after resection of colon cancer. Results of a survey of members of the American Society of Colon and Rectal Surgeons

The follow-up of patients after potentially curative resection of colon cancer has important clinical and financial implications for patients and society, yet the ideal surveillance strategy is unknown.

PURPOSE

The aim of this study was to determine the current follow-up practice pattern of a large, diverse group of experts.

METHODS

The 1,663 members of The American Society of Colon and Rectal Surgeons were asked, via a detailed questionnaire, how often they request nine discrete follow-up evaluations in their patients treated for cure with TNM Stage I, II, or III colon cancer over the first five posttreatment years. These evaluations were clinic visit, complete blood count, liver function tests, serum carcinoembryonic antigen (CEA) level, chest x-ray, bone scan, computerized tomographic scan, colonoscopy, and sigmoidoscopy.

RESULTS

Forty-six percent (757/1663) completed the survey and 39 percent (646/1663) provided evaluable data. The results indicate that members of The American Society of Colon and Rectal Surgeons generally conduct follow-up on their patients personally after performing colon cancer surgery (rather than sending them back to their referral source). Routine clinic visits and CEA levels are the most frequently performed items for each of the five years. The large majority (> 75 percent) of surgeons see their patients every 3 to 6 months for years 1 and 2, then every 6 to 12 months for years 3, 4, and 5. Approximately 80 percent of respondents obtain CEA levels every 3 to 6 months for years 1, 2, and 3, and every 6 to 12 months for years 4 and 5. Colonoscopy is performed annually by 46 to 70 percent of respondents, depending on year. A chest x-ray is obtained yearly by 46 to 56 percent, depending on year. The majority of the members of The American Society of Colon and Rectal Surgeons do not routinely request computerized tomographic scan or bone scan at any time. There is great variation in the pattern of use of complete blood count and liver function tests. Members of The American Society of Colon and Rectal Surgeons from the United States tend to follow their patients more closely than do those living in other countries. The intensity of follow-up does not markedly vary across TNM Stages I to III.

CONCLUSION

The surveillance strategies reported here rely most heavily on clinic visits and CEA level determinations, generally reflecting guidelines previously proposed in the current literature.

Perceived Religiousness is Protective for Colorectal Cancer: Data from the Melbourne Colorectal Cancer Study

The perceived or self-reported degree of ‘religiousness’ was obtained by interview from 715 colorectal cancer patients and 727 age/sex matched community controls, as part of a large, comprehensive population-based study of colorectal cancer incidence, aetiology and survival (The Melbourne Colorectal Cancer Study) conducted in Melbourne, Australia.

Self-reported or perceived ‘religiousness’, as defined in the study, was a statistically significant protective factor [relative risk (RR)=0.70, 95% confidence interval (CI)=0.6–0.9, P=0.002]. This statistically significant protection remained after the previously determined major risk factors found in the study, namely a family history of colorectal cancer, dietary risk factors, beer consumption, number of children and age at birth of the first child, were statistically corrected for ( P=0.004). There was no association between Dukes' staging of the cancer and perceived degree of ‘religiousness’ ( P=0.42). Although self-reported or perceived ‘religiousness’ was associated with a median survival time of 62 months compared with 52 months in those self-reporting as being ‘non-religious’, this difference was not statistically significant ( P=0.64).

Heredity, molecular genetics and colorectal cancer: a review

It is estimated that the hereditary polyposis and non-polyposis colorectal cancer (CRC) syndromes, which have an autosomal dominant pattern of inheritance, represent less than 10% of the total CRC burden. Thus, more than 90% of all cases of CRC have previously been considered to arise 'sporadically', with no identifiable genetic link. However, recent clinical evidence now suggests that a significant proportion of CRC seen in the general population may involve an inherited genetic susceptibility. Therefore, constructing an accurate family tree on all patients with a family history of CRC is an essential part of identifying families with an increased risk for CRC who could then be offered screening. Also, molecular genetic study of colorectal adenomas and carcinomas has led to a proposed genetic model of colorectal tumorigenesis which involves interactions between oncogenes and tumour suppressor genes. This information has important potential implications for screening, determining prognosis and for providing multiple targets for altering the sequence of malignant transformation.

Colonoscopic screening examination of relatives of patients with colorectal cancer. II. Relations between tumour characteristics and the presence of polyps

Colonoscopy was offered to 206 first-degree relatives of 181 patients operated on for colorectal cancer (CRC). Findings of polyps in relatives correlated with Dukes staging, extent of dedifferentiation and localization of tumour in the operated patient, and type of family relationship. Adenomas in relatives and Dukes staging of carcinoma in the patients were inversely related. Relatives of patients with Dukes stage A tumour had more than twice as many adenomas as and a higher prevalence of multiple adenomas than relatives of patients with advanced cancer at the time of operation. If the patient had polyp(s) in addition to tumour, the number of adenomas per relative was almost doubled. Hyperplastic polyps in relatives were associated with poorly differentiated carcinoma in their related patients. These results support the theory that not all CRC are derived from polyps and that adenoma-derived CRC may have a better prognosis than 'de novo' CRC. An adenoma prevalence risk table is also presented.

Colonoscopic screening examination of relatives of patients with colorectal cancer. I. A comparison with an endoscopically screened normal population

First-degree relatives (n = 206) of patients operated on for colorectal cancer (CRC) (n = 181) were offered a colonoscopic screening examination; 169 relatives (82%) attended. The findings were compared with those in a normal population sample with no CRC in first-degree relatives (n = 308), aged 50-59 years, who had been screened by means of flexible sigmoidoscopy. Three carcinomas and 176 polyps were found in 56 of 95 male relatives (57%) and 34 of 74 female relatives (46%). The adenoma prevalence rate was 37 (39%) and 26 (35%) for male and female relatives, respectively. In the 50- to 59-year age group, the adenoma prevalence rates for both sexes collectively and for women separately were significantly higher among relatives than among the population without CRC relatives. Hyperplastic polyps were larger, whereas adenomas were similar in size among relatives compared with the normal population. Colonoscopy may be a suitable method of choice for screening first-degree relatives of patients with CRC.

Screening for large bowel neoplasms in individuals with a family history of colorectal cancer

Logistical problems associated with population screening for colorectal cancer are identified and the possibility of targeting screening to those with a familial predisposition to the disease is discussed. Evidence for a substantial genetic effect on the overall incidence of colorectal cancer is reviewed. The screening detection rate of colorectal neoplasms in relatives of patients with colorectal cancer has been shown to be higher than that expected in a non-selected population; the evidence that polypectomy will reduce future colorectal cancer risk in such individuals is explored. Recent advances in the molecular genetics of colorectal cancer susceptibility are reviewed; it is possible that a genetic test might be developed in the future which could identify at least a proportion of those at risk. Excluding financial considerations, the risk-benefit ratio of colonoscopy in a screened population is intimately related to the remaining risk of colorectal cancer in those who undergo the examination. At present, patients undergoing colonoscopy to investigate a positive faecal occult blood (FOB) test as part of a population-based screening programme include individuals with a familial predisposition as well as those without. About 20 per cent of all cases of colorectal cancer are associated with an obvious genetic predisposition, and the risk of cancer in their relatives is high. Because false positives occur with Haemoccult, the residual risk to the population who are FOB positive but do not have a familial trait may be sufficiently low that the dangers of colonoscopy could outweigh the potential benefits. Scotland has a high incidence of colorectal cancer, and analysis of recent Scottish incidence data shows an actuarial lifetime risk of developing this disease of one in 23 for men and one in 33 for women. As a family history of the disease increases that risk by two to four times and the neoplasms arise throughout the colon in such a group, there may be a case for offering colonoscopy to all first-degree relatives of those under 50 years of age at diagnosis, if not of all index cases of colorectal cancer.

Colonoscopy in patients with a family history of colorectal cancer

Since 1982 it has been the second author's policy to advise all patients who have presented with a positive family history of bowel cancer and who are over the age of 30 years to undergo colonoscopy. In the period to August 1990, 600 such patients had at least one colonoscopy. Colorectal polyps or cancer were detected in 270 patients (45 percent). The incidence was essentially the same for the 171 patients with only second-degree relatives affected (43 percent), for the 194 patients with more than one affected relative (45 percent), and for the 429 patients with an affected first-degree relative (46 percent). Only the 55 patients with more than one affected first-degree relative had a higher incidence (67 percent). The incidence in the 136 totally asymptomatic patients was 36 percent but was 48 percent in the 464 with symptoms. In 37 patients carcinoma was diagnosed. Even in the 30- to 39-year age group there was a 29 percent incidence of polyps or carcinoma. Colonoscopic screening of patients with a family history of bowel cancer compares favorably with mass screening for breast cancer. It is currently advised that all patients over 30 years of age with a family history of colorectal cancer undergo colonoscopy on presentation and, if clear, every four years thereafter unless two first-degree relatives are affected, when it should be every two years.

Attributable risk for diet, alcohol, and family history in the Melbourne Colorectal Cancer Study

From the data obtained in a large comprehensive population-based case-control study of colorectal cancer (The Melbourne Colorectal Cancer Study), attributable risk was calculated for a family history of colorectal cancer in near relatives for diet (when > or = 5 of the 11 previously determined dietary risk factors were present) and for beer consumption (for rectal cancer only). The attributable risk was 11% in the presence of a family history of colorectal cancer and 46% in the presence of five or more dietary risk factors. The attributable risk for rectal cancer in the presence of beer consumption was 31% in males and 11% in females. These data are relevant in the consideration of primary prevention of colorectal cancer in Australia, but their general application needs to be approached with caution in view of major differences in the genetic background and the dietary practices in various regions of the world and in view of the uncertainty of what is achievable change, especially for dietary practices.

The effect of family history of cancer, religion, parity and migrant status on survival in colorectal cancer. The Melbourne Colorectal Cancer Study

The association between 5-year survival and several risk factors was investigated in 705 histologically confirmed, new cases of colorectal adenocarcinoma as one aspect of a comprehensive population-based study of large bowel cancer incidence, aetiology and survival--the Melbourne Colorectal Cancer Study. 5-year survival was not influenced by the previously determined risk of a family history of colorectal cancer in near-relatives. Similarly, other previously determined risk factors of religion, number of children, age at birth of first child and migrant status did not influence survival.

Personality as a risk factor in large bowel cancer: data from the Melbourne Colorectal Cancer Study

In a case control study which formed one arm of a large, population-based investigation of colorectal cancer incidence, aetiology and survival. 'The Melbourne Colorectal Cancer Study', among others, 22 psychosocially orientated questions were asked by personal interview of 637 histologically confirmed new cases of colorectal cancer and 714 age/sex frequency matched community controls, from Melbourne (population 2.81 million). Self-reported childhood or adult life 'unhappiness' was statistically significantly more common among the cancer cases, while 'unhappiness with retirement' was similarly distributed among cases and controls. Questions which were formulated to test a particular personality profile as a cancer risk, and which included the elements of denial and repression of anger and of other negative emotions, a commitment to prevailing social norms resulting in the external appearance of a 'nice' or 'good' person, a suppression of reactions which may offend others and the avoidance of conflict, showed a statistically significant discrimination between cases and controls. The risk of colorectal cancer with respect to this model was independent of the previously found risk factors of diet, beer intake, and family history of colorectal cancer, and was also independent of other potential confounding factors of socioeconomic level, marital status, religion and country of birth. Although the results must be interpreted with caution, the data are consistent with the hypothesis that this personality type may play a role in the clinical expression of colorectal cancer and merits further study.

Recent life change and large bowel cancer. Data from the Melbourne Colorectal Cancer Study

In a large, population based, epidemiological study of colorectal cancer, The Melbourne Colorectal Cancer Study, several etiological factors were investigated. Persons' recent life changes, as well as the degree of upset they experienced as a result of these changes, were included. Interviews with 715 histologically confirmed new cases of colorectal cancer occurring over a 12-month period in Melbourne, Australia, and with 727 age and sex matched community controls were conducted. As one of the methods of assessing any effect of recall bias, 179 hospital controls were also investigated. Major illness or death of a family member, major family problems and major work problems were found to be significantly more common for cases over the 5 years preceding diagnosis compared to controls. Cases also reported being significantly more upset with their recent life changes than did controls. No significant differences in results were found between males and females, or between colon cancer and rectal cancer patients. Although the possibility of recall bias, was not completely controlled for in this study, it was probably not an important factor in explaining case-control differences. Recent life changes, and their perceptions, may have significance in the development of large bowel cancer.

Colorectal polyps, diet, alcohol, and family history of colorectal cancer: a case-control study

A case-control study was conducted in Melbourne, Australia. Cases (n = 49) were patients who had one or more histologically confirmed adenomatous polyps larger than 1 cm in diameter previously removed by endoscopy. In both the cases and the community controls (n = 727), previous diet, alcohol consumption, and family history of colorectal cancer in near relatives were investigated. The family history rate of colorectal cancer was similar in the two groups. Those with adenomatous polyps were found to have a low fiber/vegetable intake (p = 0.04); in males, there was a high intake of beef (p = 0.04), milk drinks (p = 0.01), and beer (p = 0.05). This study provides further evidence for the hypothesis that dietary factors and alcohol consumption may play a role in the development of adenomatous colorectal polyps and that these factors are similar to dietary risk factors for colorectal cancer.

Survival in patients with large-bowel cancer. A population-based investigation from the Melbourne Colorectal Cancer Study

Five-year survival data were obtained in 97 percent or 1105 of 1140 new patients with histologically confirmed colorectal adenocarcinoma during a 12-month period in 1981 and 1982, as part of a large comprehensive population-based study of colorectal cancer incidence, etiology, and survival, The Melbourne Colorectal Cancer Study. Fifteen percent of patients were Dukes' A stage, 32 percent were Dukes' B, 25 percent were Dukes' C, and 29 percent were Dukes' D. At five years after diagnosis, the observed survival rate was 36 percent and the adjusted rate was 42 percent. Dukes' staging was a highly discriminating factor in survival (P less than 0.001). Survival rates were better in women than in men and better for patients with colon cancer than for patients with rectal cancer. Survival by Dukes' staging was not affected by colon subsite or by the tumor being the first and single tumor, metachronous tumor, or synchronous tumor. The survival of younger patients was better for Dukes' stages A, B, and C, and worse for Dukes' D. Survival was worse in the presence of bowel perforation in Dukes' C and D stages. Within Dukes' D (incurable cases), survival was best in the absence of hepatic metastases, slightly worse when only hepatic metastases were present, and poorest in the presence of both hepatic and extrahepatic metastases. Statistical modeling of survival determinants other than staging indicated that cell differentiation had the largest effect (survival decreasing with poor cell differentiation), followed by site (survival worse for rectal cancer than colon cancer), then age (survival better for younger patients), while bowel perforation had the smallest effect on survival.

Immunohistochemical demonstration of human papilloma virus antigen in human colon neoplasms

The presence of human papilloma virus (HPV) has recently been demonstrated in colon tumors, but the incidence of HPV infection in normal colon mucosa or in benign or malignant neoplasms of the mucosa is unknown. We studied both neoplastic and normal human colon tissue for the presence of HPV antigen using immunohistochemical techniques. Ninety colon specimens were studied. Three consecutive series of normal colon mucosa (N = 30), single benign tubulovillous adenomas (N = 30), and invasive carcinomas (N = 30) were selected and confirmed histologically. Formalin-fixed paraffin-embedded samples of each tissue were prepared using immunohistochemical techniques and resultant slides were read blindly and graded simply as positive or negative for HPV antigen. The presence of HPV antigen varied dramatically between groups, with 97% of the invasive carcinomas, 60% of the benign tubulovillous adenomas, and 23% of the normal mucosa positive for HPV antigen. Groups were statistically significant using chi 2 analysis (P less than 0.001). We conclude that an association exists between the human colon neoplasia and the presence of HPV antigen. This may suggest an etiologic role of the virus in colon cancer.

Oral contraceptive use does not protect against large bowel cancer

The association between oral contraceptive (OC) use and colorectal cancer was examined in 190 female colorectal cancer cases and 200 age-matched female controls in data derived from a population-based study of large bowel cancer, "The Melbourne Colorectal Cancer Study" conducted in Melbourne, Australia. There were 47 cases (24 colon cancer, 23 rectal cancer cases) and 39 controls, who were past OC users. After adjustment was made for the confounding factors of age, number of children and age at birth of first child, a statistically significant risk was found among rectal cancer OC users, but not among colon cancer OC users (RR rectal cancer = 2.04, 95% CI = 1.00-4.14, p = 0.04; RR colon cancer = 1.17, 95% CI = 0.59-2.29, p = 0.60). These risks were not affected by adjustment for socioeconomic level, country of birth, religion, previous diet and family history of colorectal cancer. Rectal cancer risk was higher among those OC users who were also beer drinkers (RR = 6.96, 95% CI 2.09-23.1, p = 0.001).

Endoscopic screening and surveillance for gastrointestinal malignancy

In the US, the cumulative lifetime risk of developing carcinoma of the upper gastrointestinal tract is less than 1 per cent, premalignant conditions are uncommon, and esophageal and gastric malignancies are rarely curable even when identified early. Endoscopic screening of the upper gastrointestinal tract in asymptomatic persons thus cannot be justified. Surveillance of persons with certain uncommon conditions associated with a higher risk of upper gastrointestinal cancer may be of benefit. These conditions include achalasia, Barrett's esophagus, chronic atrophic gastritis with intestinal metaplasia, familial polyposis coli, gastric polyps, lye stricture, Plummer-Vinson syndrome, and tylosis. In the lower gastrointestinal tract, however, the lifetime risk of developing carcinoma is 5 per cent, premalignant conditions and lesions are common, and carcinoma is curable when detected at an early stage. Sigmoidoscopic screening of asymptomatic adults has been advocated by the American Cancer Society but has not become widely practiced because of its cost, required physician effort, low overall yield, and poor patient compliance. Surveillance by flexible sigmoidoscopy is recommended for persons at slightly increased risk of colorectal carcinoma who have prior breast or gynecologic malignancy or a family history of colorectal malignancy. Colonoscopic surveillance is recommended for patients with high risk of colorectal cancer who have had prior colorectal carcinoma or adenoma or who have inflammatory bowel disease or a ureterosigmoidostomy.