Screening In Sweden Research Articles

Consistent high viral load of human papillomavirus 16 and risk of cervical carcinoma in situ: a nested case-control study

Persistent infection with certain types of human papillomavirus (HPV) is believed to be a prerequisite for the development of cervical neoplasia. Persistence may depend on certain characteristics, such as viral load, which has so far been given little attention. We investigated the association between HPV 16 viral load and cervical carcinoma in situ. We did a nested case-control study of women participating in cytological screening in Sweden. We used a sensitive quantitative PCR assay to estimate HPV 16 load in multiple smears for each woman, taken during a period of up to 26 years before diagnosis. We calculated C, values, which decrease as the number of viral DNA copies increases. 2081 smears from 478 cases and 1754 smears from 608 controls were tested. Among cases, we found a consistently increased load of HPV 16 already 13 years or more before diagnosis, and when many smears were still cytologically normal. Women with high HPV 16 viral loads were at least 30 times the relative risk of HPV-16-negative women more than a decade before diagnosis. The increase in relative risk was constant over time. About 25% of women (95% CI 0.12-0.32) infected with a high viral load before age 25 years developed cervical carcinoma in situ within 15 years. Cervical carcinoma in situ associated with HPV 16 occurs mainly in HPV-16-positive women who have consistently high viral loads long term. Women at high risk could be identified by use of a quantitative HPV test in addition to cytological screening.

Implementation of service screening with mammography in Sweden: from pilot study to nationwide programme.

Establishment of mammography screening in Sweden has progressed logically from pilot study through clinical trials to service screening. Screening with mammography for early detection of breast cancer has been provided by all Sweden's 26 county councils since 1997. It took 23 years from the initial pilot study through clinical trials to the establishment of mammography service screening throughout Sweden. In the screening rounds completed by 1995-96, and provided by all but one county council, 1040000 women participated, corresponding to 81% of those invited. The national average recall rate was 2.2%, and consequently 23000 women were recalled for additional investigations. Eleven county councils invited women aged 40-74, six invited women aged 50-69, the remaining eight invited women between both these age intervals. Mammography outside screening programmes-clinical mammography-is available throughout Sweden. About 100000 women a year were referred for clinical mammography and about 50% of these were either younger or older than those invited for screening. A negative relation between the use of clinical mammography and participation in the screening programmes was noticed.

Radiation risk and mammographic screening of women from 40 to 49 years of age: effect on breast cancer rates and years of life.

The aim of this study was to evaluate the carcinogenic risks associated with radiation in mass mammographic screening. Assessment was in terms of breast cancer mortality and years of life for a hypothetical cohort of 100 000 women. Data were obtained on incidence, mortality and life expectancy for the female population of Stockholm. With a screening interval of 18 months at ages 40–49 years, a total absorbed dose to the breast of 13 mGy per invited woman; and an annual breast cancer reduction of 25% per year 7 years from screening start, the net number of years gained was at least 2800. However, using the highest absorbed dose reported in routine mammographic screening in Sweden (≈3 mGy per view), and the highest reported radiation risk in the literature, a programme entailing annual screening with 2 views would require at least a 20% annual reduction in breast cancer mortality to give a net benefit in both the number of years of life gained and number of breast cancer deaths avoided. This observation supports the conclusion that exposures with low absorbed dose are essential when performing mass screening with mammography among young women. © 2000 Cancer Research Campaign

General practice care and patients' priorities in Europe: an international comparison

Insight into patients' priorities with respect to health care should complement the views of professionals and policy makers on what is thought to be appropriate health care. To determine the strengths and weaknesses of general practice care from patients' perspectives written surveys were performed among patients in Denmark, Germany, Israel, Netherlands, Norway, Portugal, Sweden and United Kingdom ( n=3540). The potential quality problems identified were spread over the different countries: the low involvement of general practitioners in out-of-hours services in Portugal; the low provision of routine screening in Sweden, Norway and The Netherlands; the lack of a defined patient population in Germany; the lack of a formal gatekeeper role to secondary care in general practice in Germany and Sweden; and the low number of home visits in Sweden.

Chlamydia screening in Sweden reduces the risk of ectopic pregnancy

Chlamydia screening in Sweden reduces the risk of ectopic pregnancy

Female genital organs.

In 1991, 456 new cases of cancer of the cervix uteri were reported to the Swedish Cancer Registry. The incidence of cervical cancer has decreased substantially in Sweden since the mid-1960’s. The age-adjusted incidence rate dropped from 18.2 in 1972 to 9.4 per 100 000 women in 1991 ( I ) . Current evidence indicates that one important cause of cervical cancer is infection of the cervix with the human papilloma virus (HPV). This infection is acquired most commonly through sexual intercourse, thus a possible explanation of the observed associations with number of sexual partners and age at first intercourse (2, 3). There is strong evidence that Papanicolaou smear testing may reduce both incidence and mortality of cervical cancer (4-9). The introduction of the Pap smear tests led to an increased frequency of discovered carcinoma in situ, which in turn led to early treatment and a decrease in incidence of and mortality from cervical cancer (5 . 7. 8). Since the decline in the incidence of cancer of the cervix started before the introduction of screening in Sweden, some effects must be attributed to other factors. e.g.. improvements in the public and professional awareness and more resources available in the health services (10). Current treatment for cancer of the cervix is surgery for early stages and radiotherapy for more advanced stages. Radiotherapy may also be used in combination with surgery in cases with a poor prognosis, e.g., with spread to the lymph nodes or surgically incompletely resected tumors. In patients with advanced or recurrent disease, single-agent chemotherapy constitutes the treatment of choice (9).

Evaluation of the effect on breast cancer mortality of population based mammography screening programmes.

To evaluate, by analysis of breast cancer mortality data from all the 26 Swedish counties for the years 1971 to 1990, whether the effect of the introduction of mammography screening in Sweden can be assessed by observation from existing mortality data. A Poisson regression model was used to study whether a decrease in breast cancer mortality among women aged 50-74 years was associated with the extent of mammography screening in different counties and periods. In regions where mammography screening had been introduced, breast cancer mortality tended to be decreased, on average, compared with regions without screening. If a 10 year time lag between the start of screening and its full effect on mortality is assumed then the estimated reduction in breast cancer mortality associated with introduction of screening was 19% with a 95% confidence interval ranging from -3% to 37%. The results suggest that the effect of mammography screening may be studied using existing routine mortality data and appropriate statistical modelling. This way of assessing the outcome of the screening is valuable when continuously monitoring a screening programme that has become a public health routine.

Detection of preinvasive cancer of the cervix and the subsequent reduction in invasive cancer.

Cytologic screening and follow-up can reduce the incidence of cervical cancer by detection and removal of precursor lesions. It is unknown, however, whether differences in histopathologic criteria for these precursor lesions affect the benefit of screening. These criteria may be difficult to study, but they are likely to be reflected in reported incidence of in situ cancer in small areas of Sweden. Our purpose was to test the hypothesis that the benefit of screening can be predicted by histopathologic criteria as reflected in the reported incidence of cancer in situ. Incidence data were from the Swedish National Cancer Registry. Regression models showing the relationship between in situ and invasive cancer were formulated and estimated. Each county (total, 24) was a unit of measurement, and adjustment was made for the incidence of invasive cancer before screening. During population-based screening in Sweden, the incidence of cancer in situ varied about fourfold among the 24 counties, which indicates that the criteria used to diagnose cancer in situ differed markedly. No statistically significant (P < .05) associations were found between the incidence of cancer in situ in 1965, 1970, or 1975 and the reduction in invasive cancer 5, 10, or 15 years later. According to the best-fitting model, detection of 100 extra cases of cancer in situ per 100,000 women per year in 1975 resulted in a reduction of 1.0 (95% confidence interval [CI] = -1.6-3.7) cases of invasive cancer 10 years later. The corresponding best model estimate implied a reduction of 4.6 cases (95% CI = 1.5-7.7) in a model restricted to cancer in situ in patients aged 20-50 years (when organized screening took place), invasive cancer in patients aged 30-60 years, and cancer in situ measured in 1970. The absent, or at most weak, association between detection of cancer in situ and subsequent reduction in invasive cancer indicates that relaxed histopathologic criteria for cancer in situ may result in extensive, unnecessary treatment of lesions that would regress spontaneously. Further studies are urgently needed to enable identification of neoplasms likely to progress to invasive, fatal disease.

The preventive value of audiometric screening of preschool and young school-children

The routine to screen 4- and 7-year-old children with audiometry has been studied with regard to its preventive value. Out of 2 330 4-year-olds, 27 children with secretory otitis media (SOM) were treated with myringotomy and 9 of these with grommets as a consequence of identification by screening. One child with unilateral, sensorineural impairment received special teacher's assistance 2 h per week as a consequence of identification by screening. When the same children were screened at the age of 7, 6 children with SOM were treated with myringotomy after identification by screening audiometry. Children with SOM at the age of 4 had impaired hearing at the age of 7, identified by screening, 4 times more frequently than other children. The study suggests that audiometric screening in Sweden does not have important preventive effects on hearing impairments or on sequelae of auditory deprivation.

A dissent from dr schmidt's appraisal of evidence on breast cancer screening

This commentary on Dr Schmidt’s paper, “The epidemiology of mass breast cancer screening-a plea for a valid measure of benefit” [1], was stimulated by my reaction on reviewing the paper when it was submitted for publication. The extensiveness of his analysis of benefits and risks in breast cancer screening called for a detailed assessment of his arguments rather than a dissenting note to the editors, a position with which they agreed. Dr Schmidt probes into published results of the two randomized controlled trials on breast cancer screening in Sweden and draws peripherally on some of the observations in the Health Insurance Plan project to conclude that “even with the assumption that screening can save lives, the net health effect of mass breast screening is questionable and appears to be rather detrimental.” The Swedish trials are the twocounty study in Kopparberg-astergotland [2] and the study in Malmij [3], both of which started in the late 1970s 13-14 years after the HIP trial began. Dr Schmidt’s negative conclusion is based on the observed “excess” in breast cancers detected among study groups of women in the Swedish trials and the additional surgery that results from screening; the small gain when measures of absolute differences between study and control groups in breast cancer mortality are considered instead of relative risk; questionable balance

Mass screening in Sweden for cancer of the uterine cervix: effect on incidence and mortality. An overview.

An overview of mass screening for precancer and invasive cancer of the cervix uteri in Sweden 1964-1980 is given. Results of the screening program are presented. The decrease of incidence and mortality from invasive cancer of the cervix is presented and discussed. The increase of diagnosis of cancer in situ is illustrated.

MASS SCREENING IN SWEDEN FOR CANCER OF THE UTERINE CERVIX

The mass screening program in Sweden for cancer of the uterine cervix, which was started in 1964, is now almost nation-wide. Approximately a quarter of a million women are screened every year. The attendance varies between 55 and 90%. Approximately two per cent of the screened female population is invited to further examination or treatment. The yield through the mass screening program varies between 3.5 and 10 positive cases per 1000 examined women. The incidence of cancer of cervix is decreasing. This is most evident in those counties, which have been carrying out the screening program for about ten years. The stage distribution in cancer of the cervix has not been changed by the screening program. Mortality in cancer of the cervix is unchanged. There has been an enormous increase in the number of diagnosis of cancer in situ of the cervix, which is a difficult practical problem.