Reduction in mortality from breast cancer: Presentation of benefits and harms needs to be balanced (original) (raw)
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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.
International Journal of Cancer, 2008
The aim of this study was to assess changes in the trends in breast cancer mortality and incidence from 1975 to 2006 among Dutch women, in relation to the implementation of the national breast cancer screening programme. Screening started in 1989 for women aged 50-69 and was extended to women aged 70-75 years in 1998 (attendance rate approximately >80%). A joinpoint Poisson regression analysis was used to identify significant changes in rates over time. Breast cancer mortality rates increased until 1994 (age group 35-84), but thereafter showed a marked decline of 2.3-2.8% per annum for the age groups 55-64 and 65-74 years, respectively. For the age group of 75-84 years, a decrease started in the year 2001. In women aged 45-54, an early decline in breast cancer mortality rates was noted (1971)(1972)(1973)(1974)(1975)(1976)(1977)(1978)(1979)(1980), which is ongoing from 1992. For all ages, breast cancer incidence rates showed an increase between 1989 and 1993, mainly caused by the age group 50-69, and thereafter, a moderate increase caused by age group 70-74 years. This increase can partly be explained by the introduction of screening. The results indicate an impressive decrease in breast cancer mortality in the age group invited for breast cancer screening, starting to show quite soon after implementation.
Breast cancer mortality in Copenhagen after introduction of mammography screening: cohort study
British Medical Journal, 2005
Objectives To evaluate the effect on breast cancer mortality during the first 10 years of the mammography service screening programme that was introduced in Copenhagen in 1991. Design Cohort study. Setting The mammography service screening programme in Copenhagen, Denmark. Participants All women ever invited to mammography screening in the first 10 years of the programme. Historical, national, and historical national control groups were used. Main outcome measures The main outcome measure was breast cancer mortality. We compared breast cancer mortality in the study group with rates in the control groups, adjusting for age, time period, and region. Results Breast cancer mortality in the screening period was reduced by 25% (relative risk 0.75, 95% confidence interval 0.63 to 0.89) compared with what we would expect in the absence of screening. For women actually participating in screening, breast cancer mortality was reduced by 37%. Conclusions In the Copenhagen programme, breast cancer mortality was reduced without severe negative side effects for the participants.
Paradoxes of breast cancer incidence and mortality in two corners of Europe
Background Breast cancer incidence is rising globally. Mortality rates show a heterogenous pattern, where geographical disparities might indicate influence of health policy, behavior and care provision. Early detection and treatment have been proven to have a profound impact on prognosis. Methods Breast cancer data from Sweden and Crete was derived from registries. Incidence and mortality were expressed as Age-Standardized Incidence Rates (ASIR), Age-Standardized Mortality Rates (ASMR) and survival as intervals of three consecutive enrolling years. Findings Incidence of breast cancer has for decades risen in Sweden and also on Crete. In 2019, ASIR was 217.5 in Sweden and 58.9 on Crete, (p < 0.001). Mortality rates, however, showed opposite trends. ASMR was higher on Crete (25/100.000 person years) than in Sweden (17/100.000 person years) (p = 0.04). ASMR has fallen in Sweden from 25.5 to 16.8 in the period 2005–2019, while on Crete, ASMR continued to rise from 22.1 to 25.3. Since...
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%.
International Journal of Cancer, 2001
Age-standardised breast cancer mortality rates have been stable for decades. However, rates have started to decline in several Western countries. In countries where populationbased screening programmes for breast cancer were introduced in the late 1980s or early 1990s, the key question now is to what extent screening is responsible for the reported declines in mortality. This study compares breast cancer mortality rates in Nijmegen, where a screening programme for breast cancer was introduced in 1975, to a control city, Arnhem, and to the Netherlands as a whole over a 20-year period. Age-standardised breast cancer mortality rates as well as age-standardised mortality ratios were calculated for successive calendar years from 1969 to 1997. Further, a tailor-made period-cohort-group Poisson regression model was fitted. Figures displaying age-standardised mortality rates and ratios showed inconclusive patterns with regard to the expected impact of screening. Depending on when mortality rates were allowed to deviate between populations, the period-cohort-group analysis indicated a non-significant 6% to 16% reduction in breast cancer mortality after 2 decades in favour of the Nijmegen female population. Possible explanations are discussed as to why the mortality reductions reported by randomised trials might not be observed in a public health screening programme, such as the Nijmegen programme, evaluated by comparisons of geographical trends.
Age-period-cohort modelling of breast cancer incidence in the Nordic countries
Statistics in Medicine, 2001
The Nordic countries have experienced a steady increase in breast cancer incidence throughout the past 35 years. We analysed the incidence in Denmark, Finland, Norway and Sweden during the period 1958 to 1992 using age-period-cohort models and taking the systematic mammography screening into account. Assuming the age dependency of the incidence pattern in old age to be common for the Nordic countries, an internal comparison could be made among the four countries of the cohort e ects and the period e ects. The study indicated that the period e ects have been of importance for the increase in breast cancer incidence seen in the Nordic countries. The widespread practice of neglecting the period e ects in age-period-cohort analysis of time trends in breast cancer incidence therefore probably needs reconsideration. A key ÿnding was that Danish women born in the 20th century seem to have been exposed to an increasing load of cohort borne breast cancer risk factors not experienced to the same extent by Norwegian women, whereas they were seemingly subjected to the same period e ects.
BMJ, 2010
Objective To examine changes in temporal trends in breast cancer mortality in women living in 30 European countries. Design Retrospective trend analysis. Data source WHO mortality database on causes of deaths Subjects reviewed Female deaths from breast cancer from 1989 to 2006 Main outcome measures Changes in breast cancer mortality for all women and by age group (<50, 50-69, and ≥70 years) calculated from linear regressions of log transformed, age adjusted death rates. Joinpoint analysis was used to identify the year when trends in all age mortality began to change.
The potential of breast cancer screening in Europe
International Journal of Cancer
Currently, all European countries offer some form of breast cancer screening. Nevertheless, disparities exist in the status of implementation, attendance and the extent of opportunistic screening. As a result, breast cancer screening has not yet reached its full potential. We examined how many breast cancer deaths could be prevented if all European countries would biennially screen all women aged 50 to 69 for breast cancer. We calculated the number of breast cancer deaths already prevented due to screening as well as the number of breast cancer deaths which could be additionally prevented if the total examination coverage (organised plus opportunistic) would reach 100%. The calculations are based on total examination coverage in women aged 50 to 69, the annual number of breast cancer deaths for women aged 50 to 74 and the maximal possible mortality reduction from breast cancer, assuming similar effectiveness of organised and opportunistic screening. The total examination coverage ranged from 49% (East), 62% (West), 64% (North) to 69% (South). Yearly 21 680 breast cancer deaths have already been prevented due to mammography screening. If all countries would reach 100% examination coverage, 12 434 additional breast cancer deaths could be prevented annually, with the biggest potential in Eastern Europe. With maximum coverage, 23% of their breast cancer deaths could be additionally prevented, while in Western Europe it could be 21%, in Southern Europe 15% and in Northern Europe 9%. Our study illustrates that by further optimising screening coverage, the number of breast cancer deaths in Europe can be lowered substantially.