Biomedical subjects

J O Chamberlain

Publications and source records attributed to J O Chamberlain.

10 recordsLinked to original sources

PubMed1995

Effect of retesting with dietary restriction in Haemoccult screening for colorectal cancer.

OBJECTIVES: To determine the detection rate, false positive and false negative rates associated with a policy of retesting with dietary restriction after an initial positive Haemoccult screening test for colorectal cancer, in order to compare the cost effectiveness of such a policy with the alternative, in which all subjects with a positive test would proceed directly to diagnostic colonoscopy. METHODS: Over four years in a large randomised control trial in Nottingham 35,260 subjects had a mean of 1.5 screening rounds each at two-yearly intervals, and were followed up for a minimum of 27 months. During this period subjects with positive screening tests were asked to repeat the test with dietary restrictions. Estimates of costs of the initial screening and of diagnostic colonoscopy were used to estimate the cost for each cancer detected by the different policies. RESULTS: 1209 subjects had a positive initial screening test and 1033 (85.4%) completed the retests. Four hundred and ninety nine subjects were investigated and 89 cancers detected. In the 710 subjects with negative retests six interval cancers were diagnosed in the two years after screening. If these had been detected by screening under a policy of immediate colonoscopy, test sensitivity would have been improved from 53.6% to 57.2% (P = 0.02), but the cost for each cancer detected would have increased from pound 773 to pound 1509. CONCLUSION: Retesting with dietary restrictions reduces costs and maximises the benefit of limited colonoscopy resources, but results in a small but significant reduction in test sensitivity compared with a policy for immediate colonoscopy.

Colonoscopy↗

PubMed1992

A case-control evaluation of the effect of breast cancer screening in the United Kingdom trial of early detection of breast cancer.

OBJECTIVE: The aim was to assess the extent to which selection bias affects a case-control study of breast cancer screening in which attenders and non-attenders for screening are compared. DESIGN: There were two retrospective case-control studies, one estimating the risk of death from breast cancer in women in the screening district relative to those in the comparison district (study A), the second estimating the relative risk for women who had ever been screened compared with women who had never been screened in the screening district alone (study B). For cases and controls in study B, the women's screening history was summarised for the time period from date of entry to diagnosis of the case, or the equivalent time from date of entry for the matched controls. For cases detected by screening, the screen at which cancer was detected was included in the screening history. SUBJECTS: Cases were deaths from breast cancer in women with disease diagnosed after entry to the trial, up to 31 December 1986 or a maximum of seven years from date of entry, in one of the screening districts (Guildford) and one of the comparison districts (Stoke) participating in the UK Trial of Early Detection of Breast Cancer: study A: 198 deaths in Guildford and Stoke; study B: 51 deaths in Guildford only. There were five age matched controls for each case, with length of follow up at least as great as the time from entry to death of the case. MAIN RESULTS: The estimate of the risk of death from breast cancer in the screening district relative to the comparison district from study A was 0.76, thus implying a reduction of 24% in the screening district, similar to that obtained from a cohort analysis of data from the two districts. In contrast, the relative risk in study B for ever v never screened women was 0.51, which, taking the 72% compliance into account, would result in a relative risk of 0.65 for the screening district if there were no selection bias. The risk of breast cancer mortality in the never screened relative to the comparison district was 1.13, despite the fact that incidence rates in the two populations were similar. This suggested that cancers in the never screened group had a particularly poor prognosis, contributing to selection bias. CONCLUSIONS: The possible existence of selection bias should lead to caution in interpretation of the results of case-control studies of the effect of breast cancer screening on mortality.

Breast Neoplasms↗

PubMed1991

The hospital costs of diagnostic procedures for colorectal cancer.

Diagnosis for colorectal cancer is commonly made using either colonoscopy or double contrast barium enema techniques. To data, little attention has been paid to the comparative costs of these two procedures and the paper presents estimates of hospital costs for each, using data from the colorectal study being undertaken in Nottingham, U.K. Consideration is also given to procedure sensitivity and the frequency of referral to the alternative technique in cases of incomplete diagnosis. The paper presents the conditions under which a given technique may be considered cost-superior to its alternative but concludes that the absence of conclusive clinical trial data and other considerations precludes the identification of a definitively optimum technique from the economic point of view.

Barium Sulfate↗

PubMed1991

The cost of screening for colorectal cancer.

STUDY OBJECTIVE: The aim was to make projections of the likely costs and yield resulting from the implementation of a faecal occult blood screening programme for colorectal cancer. DESIGN: Cost and clinical data were derived from the MRC colorectal screening trial currently in progress in Nottingham, UK. SETTING: The above data were used as the basis for modelling the likely implications were the trial to be reproduced as a screening programme within a "typical" family practitioner committee area. MAIN RESULTS: For an average family practitioner committee area with a target population of 75,000 subjects aged 50-74 years, the initial screening round might be expected to detect 85 cancers at a total cost of approximately 250,000 pounds. This represents a cost per cancer detected of 2700 pounds and a cost per person screened of approximately 5 pounds. For subsequent screening rounds, total costs might be expected to fall although average costs are likely to remain approximately constant. CONCLUSIONS: The model is successful in generating "order of magnitude" estimates for the costs of implementation of a screening programme for colorectal cancer. As benefit estimates are not yet available, however, no cost-effectiveness analysis can be undertaken at this stage. In general, sensitivity analyses reveal that programme costs are more sensitive to changes in clinical variables, especially detection and compliance rates, than they are to variations in the costs of resource inputs. A screening programme with a more elaborate protocol than that currently employed in the Nottingham trial will entail considerable cost increases.

Colonic Neoplasms↗

PubMed1988

A comparison of methods for increasing compliance within a general practitioner based screening project for colorectal cancer and the effect on practitioner workload.

Screening for colorectal cancer by testing for faecal occult blood (FOBT) is effective for early diagnosis, but the success of a screening programme also depends on compliance. The aims of this study were to assess the effect of health education on compliance and to assess any addition to general practitioner workload that resulted. Altogether 3860 patients were recruited and randomly allocated to test or control group. The test group was further divided into subgroups, some of which received health education. Compliance with FOBT was 54.7% (210/384) in the subgroup receiving only the doctor's letter, which fell to 48.1% (743/1544) in the group receiving health education. General practitioner consultation rates were similar in test and control groups.

Aged↗

PubMed1973