Randomised trial of compliance with screening for colorectal cancer

A randomised trial of compliance with screening for colorectal cancer by means of the haemoccult test was conducted in Farnborough and Basingstoke districts. In each of the 14 participating practices (41 general practitioners) 25 852 men and women aged between 40 and 70 years were randomly allocated by household to one of six groups. The group determined the method of invitation to screening: a letter and the test were sent to the patient, or a letter with an appointment to attend the surgery was sent, or during a routine consultation the general practitioner invited patients to participate, and some patients received an educational booklet about bowel disorders and screening. Of the 17 824 people who were offered screening, 7545 (42%) complied. Compliance was significantly affected by the method of invitation, but not by whether an educational booklet was received, and was highest (57%) in the group that was offered the haemoccult test during a routine consultation (the "opportunistic" approach). In this group the compliance rate achieved by individual general practitioners ranged from 26% to 82%. Compliance was significantly higher in Farnborough, in the older (55-70) age group, in women, and in households in which two or more people were offered screening. The higher compliance in Farnborough may be explained by the higher proportion of older people and by the higher proportion of people living in households of two or more in the population that was offered screening. The fact that the screening programme in Farnborough was offered to the whole community and that the researcher may have acted as a facilitator were probably also important. One per cent of the patients screened had a positive test, and 24 (38%) of the 63 patients who were positive and were investigated in hospital had neoplastic disease. The yield was 1.2 cancers and 1.2 benign adenomas (1 cm or larger in size) per 1000 people screened. This low yield is likely to be a consequence of the relatively young age group screened.

Factors affecting compliance in colorectal cancer screening. Results of a study performed in Ballarat

Non-compliance in screening programmes for colorectal cancer is likely to be the most important factor limiting the impact of screening on mortality. This study aimed to determine risk factors and correlates of compliance that could be readily identified by general practitioners. A total of 581 eligible subjects aged 40 to 75 years completed a questionnaire that covered demographic factors, personal medical history, family history of colorectal cancer and smoking status. Faecal occult blood tests were then offered by the general practitioner and compliance correlated with responses. The over-all compliance was 44% and increased to 51% for those who accepted the self-testing kit at consultation. For men, compliance increased with increasing level of education and was significantly greater for non-smokers than for smokers. For women, compliance increased with increasing age, and was greater for those with either symptoms and/or a family history of colorectal cancer. A doctor group-practice factor appeared to influence acceptance versus refusal of the test kit from the doctor. A triage approach to screening in general practice may improve over-all compliance and the yield of tumours. With this strategy, patients at high risk (for example, those with a family history of colorectal cancer or in older age groups) are identified first. Particular attention should be given during consultation to those at high risk who have poor compliance profiles (for example male smokers with a family history of colorectal cancer). High-risk subjects with high compliance profiles would need less attention and low-risk individuals would need least attention.

Screening flexible sigmoidoscopy by primary care physicians. Effectiveness and costs in patients negative for fecal occult blood

A total of 252 consecutive screening flexible sigmoidoscopies were done by two community-based general internists on asymptomatic patients with stool negative for occult blood. Neoplastic lesions were found in 26 patients (10.3%), including 27 adenomatous polyps, 2 with carcinoma-in-situ and 1 carcinoid tumor. No complications resulted from flexible sigmoidoscopy. Nineteen patients with positive screening sigmoidoscopy underwent colonoscopy, and additional adenomatous polyps were found in six patients (31.6%), but no additional malignancy. Total cost for screening flexible sigmoidoscopy and additional studies was $30,359 ($1,168 per patient with a polyp or malignancy and $10,119 per patient with a malignant lesion). Screening flexible sigmoidoscopy can be safely done by community-based general internists in asymptomatic patients with a diagnostic yield comparable with that reported by subspecialists; total costs are acceptable.

Bowels: beliefs and behaviour

A postal questionnaire about knowledge, beliefs, and experiences of bowel function was returned by 171 patients aged 55 years and over from a group general practice in London. Of the respondents, 10% reported no predictable frequency of movement, a higher proportion being women than men; 79% believed that a daily movement is important and 90% that 'regularity' is necessary for good health; 14% were dissatisfied with their bowel habits and 16% regularly self-treated; 95% gave reasonable definitions of 'regular' and 'diarrhoea'; a tenth were unsure about the definition of 'constipation'. Although 76% believed there were bowel symptoms which require immediate medical attention, 98% would in the first instance treat themselves for constipation, 90% for diarrhoea, and 25% for rectal bleeding. To reduce delay in the diagnosis of colorectal cancer, it is suggested that consultations for disturbance of bowel function be encouraged among the middle-aged and the elderly. Doctors should examine such patients with the diagnosis of malignancy in mind.

Determinants of primary medical practice in adult cancer prevention

The authors conducted a study of primary care physicians in the province of Quebec to ascertain their patterns of preventive practice with respect to cancer in four anatomic sites: breast, cervix, colon-rectum, and lung. They further explored the data set to elicit the determinants of the patterns of preventive practice. Scales were constructed encompassing practice behaviors for each type of cancer, continuing education intensity, knowledge, and belief. The content of these scales was delineated through factor analysis and their reliability assessed using Cronbach's alpha. Other variables were also considered in the conceptual model. Bivariate analysis and multivariate techniques were used. The models tested contained many significant interaction terms. A limited number of the first-order interactions was explored for each of the dependent variables. Different patterns emerged for each cancer type. Mode of reimbursement, continuing education, gender of physician, provider-related barriers to prevention, and knowledge were found to be the major predictors of prevention scores for the cancers studied, but their relative importance varied according to each cancer. The importance of better understanding the determinants of physician behaviors is emphasized and the existence of several possible explanatory models suggested.

[Early diagnosis of colorectal cancer: technical problems and acceptability]

There has been little change in the survival rate of colorectal cancer over the last 20 years. Earlier diagnosis probably offers the best hope for improving this survival. At the present time, the only practical method of population screening is by the detection of occult blood in the faeces. Almost all published screening trials are uncontrolled. Although cancer detected by occult blood screening tends to be at a relatively early stage, only controlled trials can answer the critical question of whether screening decreases mortality from bowel cancer. High risk patients (prior adenoma or colorectal cancer, extensive colitis of more than 10 years duration, family history of polyposis) should have colonoscopy at regular intervals.

General practitioners' awareness of colorectal cancer

A survey was carried out in Portsmouth to find out what general practitioners knew about colorectal cancer and what their views were on screening. A random sample of general practitioners was interviewed by questionnaire and the remainder asked to complete the questionnaire themselves. The overall response rate was 62%. There was a higher response rate from women doctors and from the group that was interviewed. For some questions there was a difference in the pattern of responses given by the interview group and the group who completed the questionnaire themselves.The level of knowledge of colorectal cancer varied according to which aspect was questioned. The general practitioners knew the symptoms well but were less aware of the vital statistics and risk factors. Most doctors were not in favour of screening by testing for faecal occult blood.

Carcinoembryonic antigen

The level of carcinoembryonic antigen (CEA) is often elevated in the serum of patients with cancer. This article reviews the clinical usefulness of this observation. Carcinoembryonic antigen is not useful for detecting asymptomatic cancer; its sensitivity and specificity are not high, particularly for early stages of disease, so in populations with low prevalence of disease there are many false-positive and false-negative results. Similarly, the antigen level cannot, by itself, provide enough diagnostic certainty to confirm or rule out suspected cancer. For some cancers, antigen levels at the time of diagnosis provide more precise prognosis than staging alone, but this information does not lead to more effective treatment. Serial measurement of CEA levels after surgery in patients with colorectal cancer can detect recurrences early, but few lives can be saved by this approach. Thus, CEA assays provide accurate information about some aspects of cancer but rarely lead to better outcomes for patients.

Flexible sigmoidoscopy for screening in primary practice. A key to improved survival in colon cancer

Numerous recommendations have been made in recent years regarding periodic screening for colon disease, specifically cancer. Early detection and treatment are essential for improved survival rates, and patient education is the key to success. Important factors in a screening test are reasonable cost and ease of performance. Testing for fecal occult blood fulfills these requisites but lacks specificity. Digital rectal examination should be done regularly but has limitations. Because flexible fiberoptic sigmoidoscopy has a high acceptance rate, low complication rate, and high yield and is relatively easy to perform, this procedure should be in the diagnostic armamentarium of all primary care physicians. Results of 129 flexible sigmoidoscopies performed by primary care physicians at Scripps Clinic indicate the usefulness of this procedure as a screening test for colon cancer.

Cancer surveillance. Who stands to benefit?

Currently, surveillance or risk-oriented follow-up of patients in the individual practice setting may be the most efficacious means of reducing the morbidity and mortality associated with selected types of cancer. Intervention into carcinogenesis or alteration of the natural history of cancer requires a clear understanding of the pathogenesis of the disease and patient acceptance of interval surveillance. Because etiologic information and patient compliance are frequently limited, careful scrutiny of recommendations for cancer screening or prevention is essential. It is through taking detailed family, occupational, and carcinogen-exposure histories and doing a thorough physical examination that the primary care physician can best utilize information regarding the risk of cancer and the benefits of available methods of prevention and treatment.

Health practices and illness cognition in young, middle aged, and elderly adults

The present paper examines reported frequencies of 21 health practices, beliefs that these health practices can prevent six different illnesses, and beliefs about those illnesses in a community sample of 396 people: 173 young (20 to 39 years), 111 middle-aged (40 to 59 years), and 112 elderly adults (60 to 89 years). Elderly respondents report higher frequencies of health-promoting actions (e.g., regular medical check-ups, avoidance of salt, regular sleep, and eating a balanced diet) than younger respondents. Health practices aimed at reinterpreting stress and controlling emotions (e.g., avoiding emotional stress, staying mentally alert and active) also increased with age. Belief that these 21 practices prevent specific illnesses was consistent across the three age groups. Beliefs about the six illnesses were consistent across age with three exceptions: Elderly people considered themselves more vulnerable to disease, saw it as more serious for them, and were less likely to use chronic mild symptoms, like weakness and aches, as illness warnings.

Effect of warfarin on cell kinetics, epithelial morphology and tumour incidence in induced colorectal cancer in the rat

The effect of low dose warfarin and high dose warfarin on epithelial cell kinetics (as determined by stathmokinetic techniques), and preneoplastic morphological changes was studied during azoxymethane induced carcinogenesis in the rat. Warfarin, at either low or high dose, had no effect on crypt cell production rate (CCPR) at any time interval whereas tumour incidence in both low dose warfarin and high dose warfarin groups was significantly reduced. Morphological changes were observed using scanning electron microscopy, which by conventional histology were shown to be adenoma precursors. In the control group the number of microadenomas increased with time after starting azoxymethane. In warfarin treated animals, the number of microadenomas also increased with time, but the actual incidence was reduced when compared with controls. These results suggest that the effects of warfarin on tumour development is unrelated to its anticoagulant effect, because increased dose did not result in greater tumour reduction. Furthermore, there was no overall change in CCPR when warfarin was administered. Warfarin may exert a specific effect, by preventing neoplastic change in cells which have undergone morphologically undetectable changes associated with early carcinogenesis.