Trends in breast cancer stage distribution before, during and after introduction of a screening programme in Norway

Abstract

Incidence of localized breast cancer increased significantly among women aged 50-69 years old after introduction of screening, while the incidence of more advanced cancers was not reduced in the same period when compared to the younger unscreened age group.

Effect of implementation of the mass breast cancer screening programme in older women in the Netherlands: population based study

“…23 Finally, a recent Norwegian study showed that the incidence of advanced stage breast cancer in women aged 50-69 years did not increase after implementation of mass screening. 24 Hence our findings are mostly in line with these studies that included younger women and may suggest that the capacity for screening to impact the incidence of advanced breast cancer may be limited.…”

“…29 As a result of these types of bias, several studies state that the most appropriate way to study the benefits of a screening programme on incidence rates of advanced tumours in population based studies is to investigate the effects of the screening programme. [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32] Esserman et al proposed three hypothetical scenarios after implementation of a breast cancer screening programme in the overall population, independent of age. 17 In the most ideal scenario, the incidence of early stage tumours increases while the incidence of advanced stage tumours decreases and the total number of cases remains equal.…”

The impact of mammography screening programmes on incidence of advanced breast cancer in Europe: a literature review

“…The increase in node-positive disease is likely to be population-specific and will depend on the rate of change of local surgical policy. However, reductions in node-positive disease as a results of screening are likely to be underestimated rather than overestimated due to the stage migration.[12–14, 19, 29–43]9Missing data on tumour stageWhatever staging system is being used, the introduction of a screening programme tends to bring an improved quality of breast cancer registration, with a sharp decrease in the proportion of unknown-stage cancers.Because more cases are increasingly placed in all known-stage categories, an apparent increase in all stage-specific rates occurs – including ABCR.[8, 15, 30, 32, 33, 38, 39]10Statistical approachThe statistical approach is not standardised, and includes the provision of purely descriptive information and the use of methods which are difficult to interpret, such as joinpoint analysis.Descriptive information does not allow evaluation of the magnitude and significance of observed changes in ABCR. Methods like the joinpoint analysis are useful for assessing the points in time when ABCR begins to decrease and when it stabilizes, but may be misleading when used to assess the significance of the trend.…”

Características clínico-patológicas e estadiamento ao diagnóstico de pacientes com câncer de mama em um centro de saúde do interior de Minas Gerais

“…A conclusão deste estudo é de que a probabilidade de se evitar mortes pela doença é superior aos prejuízos de se realizar o rastreamento 21 . Em outro recente estudo sobre rastreamento realizado na Noruega, Lousdal et al 22 encontraram que a incidência anual de câncer de mama localizado passou de 63,9 para cada 100.000 antes da introdução do rastreamento para 141,2 após sua introdução 22 . Por fim, no que diz respeito à mortalidade por câncer de mama, tanto os avanços no diagnóstico quanto no tratamento são peças essenciais para a sua redução.…”