Using the European guidelines to evaluate the Norwegian Breast Cancer Screening Program (original) (raw)
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Comparing Screening Mammography for Early Breast Cancer Detection in Vermont and Norway
JNCI Journal of the National Cancer Institute, 2008
Background Most screening mammography in the United States differs from that in countries with formal screening programs by having a shorter screening interval and interpretation by a single reader vs independent double reading. We examined how these differences affect early detection of breast cancer by comparing performance measures and histopathologic outcomes in women undergoing opportunistic screening in Vermont and organized screening in Norway. Methods We evaluated recall, screen detection, and interval cancer rates and prognostic tumor characteristics for women aged 50-69 years who underwent screening mammography in Vermont (n = 45 050) and in Norway (n = 194 430) from 1997 through 2003. Rates were directly adjusted for age by weighting the rates within 5-year age intervals to reflect the age distribution in the combined data and were compared using two-sided Z tests. Results The age-adjusted recall rate was 9.8% in Vermont and 2.7% in Norway (P < .001). The age-adjusted screen detection rate per 1000 woman-years after 2 years of follow-up was 2.77 in Vermont and 2.57 in Norway (P = .12), whereas the interval cancer rate per 1000 woman-years was 1.24 and 0.86, respectively (P < .001). Larger proportions of invasive interval cancers in Vermont than in Norway were 15 mm or smaller (55.9% vs 38.2%, P < .001) and had no lymph node involvement (67.5% vs 57%, P = .01). The prognostic characteristics of all invasive cancers (screen-detected and interval cancer) were similar in Vermont and Norway. Conclusion Screening mammography detected cancer at about the same rate and at the same prognostic stage in Norway and Vermont, with a statistically significantly lower recall rate in Norway. The interval cancer rate was higher in Vermont than in Norway, but tumors that were diagnosed in the Vermont women tended to be at an earlier stage than those diagnosed in the Norwegian women.
Breast cancer mortality in Norway after the introduction of mammography screening
International Journal of Cancer, 2013
An organized mammography screening program was gradually implemented in Norway during the period 1996-2004. Norwegian authorities have initiated an evaluation of the program. Our study focused on breast cancer mortality. Using Poisson regression, we compared the change in breast cancer mortality from before to during screening in four counties starting the program early controlling for change in breast cancer mortality during the same time in counties starting the program late. A follow-up model included death in all breast cancers diagnosed during the follow-up period. An evaluation model included only breast cancers diagnosed in ages where screening was offered. The study group had been invited for screening one to three times and followed for on average of 5.9 years. In the follow-up model, 314 breast cancer deaths were observed in the study group, and 523, 404 and 638, respectively, in the four control groups. The ratio between the changes in breast cancer mortality between early and late starting counties was 0.93 (95% confidence interval [CI] 0.77-1.12). In the evaluation model, this ratio was 0.89 (95% CI: 0.71-1.12). In Norway, where 40% of women used regular mammography prior to the program, the implementation of the organized mammography screening program was associated with a statistically nonsignificant decrease in breast cancer mortality of around 11%.
Cancer, 2002
BACKGROUND. The evaluation of organized mammographic service screening programs is a major challenge in public health. In particular, there is a need to evaluate the effect of the screening program on the mortality of breast carcinoma, uncontaminated in the screening epoch by mortality from 1) cases diagnosed in the prescreening period and 2) cases diagnosed among unscreened women (i.e., nonattenders) after the initiation of organized screening.
Radiology, 2011
From the Departments of Mammography (LT), Surgery (AC), and Pathology (TT), Falun Central Hospital, Falun, Sweden; Department of Mammography, University of Linköping, Linköping, Sweden (BV); Graduate Institute of Epidemiology and Preventive Medicine, National Taiwan ...
Journal of Medical Screening, 2007
Objectives To study the effectiveness of service screening with mammography in Northern Sweden. Setting Two counties which invited women aged 40-74 years to service screening with mammography were compared with two counties where service screening started 5-7 years later. There were 109,000 and 77,000 women in the study and control counties, respectively. Methods Cohorts in the study group were defined to include only breast cancer cases diagnosed after their first invitation to screening. Two outcome measures for breast cancer mortality were used; excess mortality and underlying cause of death (UCD). Detection mode was used to estimate the efficacy of screening for those women who actually attended screening. The cohorts were followed for 11 years. Results The relative rate (RR) of breast cancer death as excess mortality and UCD for women aged 40-74 years invited to screening, compared with women not yet invited, was 0.70 (95% confidence interval [CI] 0.56-0.87) and 0.74 (95% CI 0.62-0.88), respectively. The largest effect was seen in women aged 40-49 years (RR ¼ 0.64 and RR ¼ 0.62 for excess mortality and UCD, respectively). RR in age 40-74 years for women actually screened was 0.65 (95% CI 0.51-0.84) and 0.70 (95% CI 0.57-0.86) for excess mortality and UCD, respectively. The number of women needed to screen to save one life was 912 after 11 years of follow-up. Conclusions This study confirms previous findings in the earlier follow-up and indicates a long-term reduction of breast cancer mortality by 26-30%. The efficacy among those who actually attended screening was about 5% larger.
Acta Oncologica, 2006
The aim of the present study was to relate the time trends in breast cancer incidence and mortality to the introduction of mammography screening in the Nordic capitals. Helsinki offered screening to women aged 50 Á59 starting in 1986. The other three capitals offered screening to women aged 50 Á69 starting in 1989 in Stockholm, 1991 in Copenhagen, and 1996 in Oslo. Prevalence peaks in breast cancer incidence depended on the age groups covered by the screening, the length of the implementation of screening, and the extent of background opportunistic screening. No mortality reduction following the introduction of screening was visible after seven to 12 years of screening in any of the three capitals where significant effects of the screening on the breast cancer mortality had already been demonstrated by using other analytical methods for the evaluation. No visible effect on mortality reduction was expected in Oslo due to too short an observation period. The study showed that the population-based breast cancer mortality trend is too crude a measure to detect the effect of screening on breast cancer mortality during the first years after the start of a programme.
The Breast, 2004
The aim of this study was to analyse individual cases of lethal breast cancer and not to evaluate the screening programme. Women aged 40À74 years who were diagnosed with breast cancer in 1990À94 and died on or before 31 December 1998, during the gradual introduction of organised mammography service screening in north Sweden, were included in the study. Out of 342 breast cancer deaths, 280 (82%) were in symptomatic patients whose cancers were clinically detected. Most breast cancers that proved fatal were already in an advanced stage and/or of high histological grade at the time of detection. A shift towards a lower stage was seen among screen-detected and interval-detected fatal cases. In a few of the cases with fatal outcome, in patients primarily presenting with histological grade I tumours of various sizes or small screen-detected tumours less than 10 mm in size, early diagnosis by mammography followed by state-of-the-art treatment did not seem to have been enough to prevent death.