Increasingly strong reduction in breast cancer mortality due to screening.

BACKGROUND: Favourable outcomes of breast cancer screening trials in the 1970s and 1980s resulted in the launch of population-based service screening programmes in many Western countries. We investigated whether improvements in mammography and treatment modalities have had an influence on the effectiveness of breast cancer screening from 1975 to 2008. METHODS: In Nijmegen, the Netherlands, 55,529 women received an invitation for screening between 1975 and 2008. We designed a case-referent study to evaluate the impact of mammographic screening on breast cancer mortality over time from 1975 to 2008. A total number of 282 breast cancer deaths were identified, and 1410 referents aged 50-69 were sampled from the population invited for screening. We estimated the effectiveness by calculating the odds ratio (OR) indicating the breast cancer death rate for screened vs unscreened women. RESULTS: The breast cancer death rate in the screened group over the complete period was 35% lower than in the unscreened group (OR=0.65; 95% CI=0.49-0.87). Analysis by calendar year showed an increasing effectiveness from a 28% reduction in breast cancer mortality in the period 1975-1991 (OR=0.72; 95% CI=0.47-1.09) to 65% in the period 1992-2008 (OR=0.35; 95% CI=0.19-0.64). CONCLUSION: Our results show an increasingly strong reduction in breast cancer mortality over time because of mammographic screening.

Breast cancer screening case-control study design: impact on breast cancer mortality.

BACKGROUND: Recent case-control studies on the effectiveness of population-based breast cancer screening show differences in the magnitude of breast cancer mortality reduction. We investigated the role played by aspects of the case-control study design on these differences, e.g. the definition of cases and exposure to screening. MATERIAL AND METHODS: We investigated six case-control studies conducted in East Anglia (UK), Wales, Iceland, central and northern Italy, South Australia and The Netherlands. RESULTS: The breast cancer mortality reduction in the different case-control studies ranged from 38% to 70% in the screened versus the nonscreened women. We identified differences in design, e.g. the inclusion or exclusion of the first years of screening, and the correction factor for self-selection bias. CONCLUSIONS: Overall, the design of the case-control studies was similar. The differences in the magnitude of breast cancer mortality reductions are therefore unlikely to be caused by variations in the design of the case-control studies. These differences must be due to other factors, like the organisation of the service screening programme and the attendance rate. The reduction in breast cancer mortality estimated in these case-control studies indicates that the impact of current mammographic screening is at least consistent with the effect reported by the former randomised screening trials.

Large increase in a Dutch woman's lifetime risk of developing breast cancer.

A large increase in the incidence of breast cancer has been observed in many countries over the last two decades. On the other hand, however, breast cancer mortality has decreased. The prominent burden of breast cancer in the female population induces a lot of discussion about incidence and mortality rates, whereas lifetime risks are less mentioned. This study provides information on the changes in risks for Dutch women with regards to being diagnosed with breast cancer (both invasive and in situ) or dying from this disease during the screening era. We used the life table method to calculate lifetime risks for the period 1989-2003. The lifetime risk for developing breast cancer increased from 1 in 10 in 1989 to 1 in 7 in 2003; the risk of dying from breast cancer decreased respectively from 1 in 22 to 1 in 26. The increasing incidence is alarming but has to be seen in perspective; the decreasing mortality is promising and shows that, at most, one third of the breast cancer cases are fatal.

Physiologic response of the six-minute walk test in children with juvenile idiopathic arthritis.

OBJECTIVE: To determine the physiologic response of the 6-minute walk test (6-mwt) in children with juvenile idiopathic arthritis (JIA). METHODS: Eighteen children with JIA (age 7-17 years; 6 boys, 12 girls) performed a 6-mwt and a maximal exercise test. RESULTS: The physiologic response of the 6-mwt was on average between 80% and 85% of the peak values of heart rate and oxygen uptake (VO2peak) during the maximal exercise test, except for the minute ventilation, which had a mean percentage of 68.5%. Backward regression analysis showed that height and distance walked were the best predictors of VO2peak during cycling (R2 = 0.883, P < 0.001). During the 6-mwt, the difference between the first and second minute was significant in every variable, except for heart rate. The range of walking distance of children with JIA was comparable with that of healthy elderly people. CONCLUSION: The physiologic response of the 6-mwt is at a submaximal, intense level of exercise. The course of the responses during the 6-mwt was normal. The 6-mwt can be regarded as a good test for measuring functional exercise capacity.