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Journal Articles
Diagnostic accuracy of immunochemical faecal occult blood test for gastric cancer.
H Nakama, N Kamijo, K Fujimori, AS Fattah, and B Zhang. J Med Screen 1996 3: 113-114.
OBJECTIVES: To investigate the accuracy of the immunochemical occult blood test in screening for gastric cancer and to evaluate whether or not the upper digestive tract should be examined when the occult blood test is positive but there is no abnormal sign in the colorectum.
METHODS: In a case-control study an occult blood test was carried out on 150 subjects with gastric cancer, 150 subjects with colorectal cancer, and on 300 healthy subjects. Data were analysed from 44,996 persons attending a population screening programme who underwent both radiological gastric cancer screening (barium meal) and colorectal cancer examination by occult blood test.
RESULTS: In the case-control study the occult blood test was positive in 27/150 (18%) subjects with gastric cancer, in 112/ 150 (75%) subjects with colorectal cancer, and in 24/300 (8%) healthy controls. In the population screening programme the occult blood test was positive in 4/50 (8%) persons with gastric cancer and 3232/ 44,950 (7%) persons without gastric cancer, indicating no difference between them.
CONCLUSIONS: These data show that the immunochemical faecal occult blood test is worthless as a screening test for gastric cancer, and that examination of the upper digestive tract is unnecessary in cases where the faecal occult blood test is positive but there is no sign of colorectal disease.

Characteristics of colorectal cancer with false negative result on immunochemical faecal occult blood test.
H Nakama, N Kamijo, K Fujimori, A Horiuchi, AS Fattah, and B Zhang. J Med Screen 1996 3: 115-118.
OBJECTIVES: A comparative study was carried out to clarify the clinicopathological features of colorectal cancer diagnosed after a false negative result on the immunochemical faecal occult blood test.
METHODS: 236 patients with colorectal cancer were studied: 48 patients with negative results and 188 patients with positive results with the faecal occult blood test. The two groups were compared according to their age and sex and by the site, size, macroscopic type, Dukes's classification, and histological type of their cancer lesions. Additionally, the above factors were investigated prospectively and compared in 40 cases of colorectal cancer cases diagnosed as false negative and in matched cases diagnosed as true positive in cancer screening by the immunochemical faecal occult blood test.
RESULTS: In both the hospital based case-control study and the screening programme based nested case-control study the prevalence of rectal cancers was higher in the false negative group than in the true positive group (P = 0.02, P = 0.03), but there were no differences between the two groups for any other factors.
CONCLUSION: These results suggest that the immunochemical faecal occult blood test is unsuitable for the diagnosis of rectal cancer.

Reliability of underlying incidence rates for estimating the effect and efficiency of screening for breast cancer.
P Prior, CB Woodman, S Wilson, and AG Threlfall. J Med Screen 1996 3: 119-122.
The process of setting screening performance targets requires an estimate of what the incidence of breast cancer would have been in the population invited for screening if there had not been a screening programme. Before the introduction of the National Health Service breast screening programme in 1988 the incidence of breast cancer was already increasing in the population targeted for screening. To establish the incidence before screening the most recent complete data from all the regional cancer registries were collated. An age-period model was constructed to predict what these incidence rates might now have been if the screening programme had not been introduced. The model predicted that if prescreening trends continued (between 1987 and 1995) underlying incidence over this period would increase by 2.3 per 10,000 in women aged 50-54, 2.6 per 10,000 in women aged 55-59, and 2.9 per 10,000 in women aged 60-64. If the prescreening trends have continued then the use of a universal rate, applied across all calendar years and age groups, would seem to be inappropriate when setting targets.

An evaluation of the prevalent round of the breast screening programme in south east Thames, 1988-1993: achievement of quality standards and population impact.
L Garvican and P Littlejohns. J Med Screen 1996 3: 123-128.
OBJECTIVE: To evaluate the impact of the prevalent round of the NHS breast screening programme on the whole population of women aged 50-64 during the period 1988-92, by comparing the numbers of cancers detected at screening with those diagnosed symptomatically, in one United Kingdom health region (population 3.5 million). To relate this impact to the achievement of national quality standards and the observed sensitivity and specificity of the programme.
METHOD: The breast screening programme computer systems and the Thames Cancer Registry database were used to diagnose cancers in women aged 50-64 during the period 1988-1992, who were classified into screen detected, interval cases, eligible but not yet invited, non-attenders, and those not registered with the programme.
RESULTS: The programme met all national quality assurance targets for uptake, diagnostic process, and detection, but screen detected cases comprised only 48% of those diagnosed during 1991 and 1992 when the breast screening programme was fully operational. As fewer than 40% of breast cancers registered occur in the eligible age range, this limits the impact of the programme to the possible early diagnosis of only 20% of all cases. A surprisingly high proportion occurred in women unknown to the programme, especially in inner London. The high number of interval cancers led to a programme sensitivity of only 73%, but 99.7% of women screening negative were correctly reassured as a result of screening- and for them the breast screening programme is a success.
CONCLUSION: Despite achievement of quality standards, the breast screening programme is apparently having a low impact on the overall diagnosis of breast cancer in South East Thames, so a large mortality reduction due to screening alone is unlikely. Population coverage will need to be improved, and it may be necessary to reduce the screening interval, or extend the age range, or both.

The Swedish randomised mammography screening trials: analysis of their effect on the breast cancer related excess mortality.
LG Larsson, L Nystrom, S Wall, L Rutqvist, I Andersson, N Bjurstam, G Fagerberg, J Frisell, and L Tabar. J Med Screen 1996 3: 129-132.
OBJECTIVE: To apply an indirect method for estimation of the breast cancer related excess mortality in the Swedish randomised mammography screening trials.
SETTING: Randomised trials on mammography screening have, in Sweden, been performed in the counties of Kopparberg (W) and Ostergotland (E), the so called WE study, and in the three largest cities in Sweden, Stockholm (southern part), Gothenburg, and Malmo. An overview of the trials was presented in the Lancet in 1993 and included 156,911 women in the invited group and 125,866 in the control group.
METHODS: The excess mortality in the breast cancer subgroups was estimated by indirect standardisation using official national cause of death statistics according to Statistics Sweden as a reference.
RESULTS: The estimated reduction of the breast cancer related mortality was 24% for the whole group (40-74 years at randomisation). The corresponding figures for the age groups 40-49, 50-59, and 60-69 years were 6%, 28%, and 34% respectively.
CONCLUSION: The results are very similar to those presented earlier based on the traditional comparison of the breast cancer mortality in the invited and in the control group. This analysis further strengthens previous reports on a beneficial effect of mammography screening, which is especially pronounced in the age group 50-69.

Characteristics of subgroups of attenders and non-attenders in an organised screening programme for cervical cancer.
LP Larsen and F Olesen. J Med Screen 1996 3: 133-139.
OBJECTIVE: Several studies have compared attenders and non-attenders in organised cervical screening programmes but few have analysed subgroups of attenders and non-attenders. This study presents social and other characteristics of such subgroups.
SETTING: Aarhus County, Denmark.
METHODS: A case-control study in a cohort of 133,500 women, aged 23-60, included in the programme from 1 October 1990 to 1 April 1994. The participation rate was 75%, and those taking part comprised women with opportunistic screening or who had had a smear owing to symptoms in the previous three years ("active" attenders), and women who were invited for screening because they had not been otherwise tested ("passive" attenders). "Passive" (n = 708) and "active" attenders (n = 692) were compared. Women who had never had a smear test ("never" attenders, n = 287) were then compared with "ever" attenders (n = 1215)-that is, women who had not had a smear test during the previous 42 months, but had had at least one previous test. Data were collected by mailed questionnaires.
RESULTS: The response rate was 81% and 53% for attenders and non-attenders, respectively. After correction for age, there was no difference between the "active" and "passive" attenders for cancer risk factors (smoking, age of first intercourse, number of sexual partners, and social group), or in the degree of responsibility for close relatives, but "active" attenders seemed to have more frequent contact with their general practitioner. "Never" attenders had less frequent contact with their general practitioner than "ever" attenders. They were more often living alone and nullipara, but had no overrepresentation of cancer risk factors.
CONCLUSIONS: Increased effect cannot be obtained by focusing on the described groups, but by increasing the participation rate. "Never" attenders do not belong to a special risk group.

Relation between the incidence of invasive cervical cancer and the screening interval: is a five year interval too long?
A Herbert, K Stein, TN Bryant, C Breen, and P Old. J Med Screen 1996 3: 140-145.
OBJECTIVE: To examine the incidence of invasive cervical cancer per 100,000 women years at risk and relative risk according to screening history among eligible women aged 25-69 in Southampton and South West Hampshire during the three years after completion of the first round of comprehensive screening.
RESULTS: There was a significantly higher incidence of invasive cervical cancer in women who had not been screened during the preceding 0.5-5.5 years than in those who had been screened (relative risk (RR) 2.6; 95% confidence interval (CI) 1.6 to 4.3). Among the latter group of women (with interval cancers) there was a significantly higher incidence in those with a long interval of 3.5-5.5 years since their most recent smear than in those with a short interval of 0.5-3.5 years (RR 2.2; 95% CI 1.3 to 3.8). Among women with non-interval cancers, there was a significantly higher incidence among those who had no cytology record than among those who had been screened but were overdue for a smear (RR 3.0; 95% CI 1.2 to 7.3). When screen detected cancers were excluded from the figures the relative risks for all the comparative groups described above were greater, though the 95% confidence limits were wider because the numbers were smaller. The most pronounced difference in incidence was between symptomatic cancers in women with a short screening interval (5.8 per 100,000 women years at risk) and in women with no cytology record (71.3 per 100,000 years at risk). Most cancers were interval cancers (76%) because of the high screening coverage: 89.2% of eligible women aged 25-69 had been screened during the preceding 0.5-5.5 years. The overall incidence per 100000 women years at risk approached that of interval cancers, and was nearer to that observed in the short than the long interval because 74.7% of women had been screened within 3.5 years.
CONCLUSION: The results confirm the effectiveness of screening but suggest that a five year screening interval may be too long, at least during the early rounds of screening.

A collaborative approach to cervical cancer screening.
WJ Brown and JE Byles. J Med Screen 1996 3: 146-153.
OBJECTIVE: The main objective of this project was to evaluate a collaborative nurse and general practitioner approach to improve screening for cervical cancer.
DESIGN: Multiple group time series design.
SETTING: Six postal areas in the Hunter Valley of New South Wales, Australia, chosen as intervention sites because of very low Pap test rates compared with the rest of NSW (fewer than 50% of women screened). Six regions of similar size and with similar baseline screening levels were selected as comparison sites.
SUBJECTS: All women selected in the resident postal areas.
INTERVENTIONS: Women's health nurses worked in collaboration with general practitioners within the communities selected from within the Hunter area to promote and provide screening for cervical cancer.
MAIN OUTCOME MEASURES: Qualitative information on initial expectations and impressions of the collaborative processes were collected at the start of the project period. Process data on client characteristics and Pap test results were obtained from minimum data collections; client satisfaction was assessed from client surveys. Outcome data on the increase in the number of women in each community who were screened for cervical cancer were obtained from Health Insurance Commission claims for screening Pap tests (and from nurses' records where Pap tests were examined under block funding arrangements).
RESULTS: This project showed that nurses and general practitioners can collaborate to provide appropriate and highly acceptable cervical cancer screening services for women. Many of the women screened by the nurses were in the high risk age range for cervical cancer (40 years and older) and had only basic education levels, thus representing women who are most likely to have poor screening rates. Further, 33.1% of the women screened had not had a Pap test in the past four years or had never been screened. The number of women having a Pap test during the first six months of the project, compared with the number expected from preintervention patterns, was significantly greater in four intervention areas (P < 0.01). No corresponding increase was seen in comparison areas with similar screening rates at baseline.
CONCLUSIONS: There is great potential for nurses to work in collaboration with general practitioners to improve the availability and coverage of community cervical cancer screening programmes.

Cost effectiveness of screening for primary open angle glaucoma.
JF Boivin, M McGregor, and C Archer. J Med Screen 1996 3: 154-163.
OBJECTIVES AND SETTING: To determine the cost effectiveness of screening for glaucoma.
METHODS: Information on treatment efficacy, diagnostic methods, epidemiological characteristics of glaucoma, and costs were determined from the literature, from administrative databases, and from experts. Scenarios with different screening frequency, age, participation in screening, compliance with treatment, treatment efficacy, and diagnostic tests were examined.
RESULTS: The initial scenario comprised three-yearly screening of subjects aged 40-79 by funduscopy and tonometry, followed by perimetry when abnormalities were discovered. The assumption of levels of participation in screening and of compliance with treatment of 75%, and treatment efficacy of 50% resulted in a cost of $C100,000 per year of blindness prevented. A scenario in which screening was restricted to subjects aged 65-79, with the same input variables, would prevent 81% of the cases of blindness prevented with scenario 1, at a cost of $C42,000 per year of blindness prevented. Screening with tonometry only as the initial diagnostic test in subjects aged 65-79 would result in a cost of $C36,000 per year of blindness prevented, but would only prevent 59% of the cases prevented with scenario 1.
CONCLUSIONS: There is as yet no proof that treatment of glaucoma or of high intraocular pressure will arrest the progression of glaucoma to blindness. Even when treatment efficacy is assumed to be as high as 50%, however, the cost effectiveness of most glaucoma screening programmes considered would not be competitive.

Comments
What is genetic screening?
PS Harper. J Med Screen 1996 3: 165-166.

Testicular cancer. Screening, self examination, and evidence-based medicine.
J Wardle. J Med Screen 1996 3: 165.

Letter
Testicular cancer. Incidence of testicular cancer.
JK Morris. J Med Screen 1996 3: 165.

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