screening detected breast cancer - treatment unnecessary?

new_direction

Natural history of breast cancers detected in the Swedish mammography screening programme: a cohort study:
http://www.thelancet.com/journals/lanonc/article/PIIS1470-2045(11)70250-9/abstract

"the more diagnoses the more women need treatment"

Is this the reason why treatment is statistically "getting better"? because we now treat cancer which would have disappeared by itself anyway?

is this a "hoax" to keep us optimistic about treatment - making us believe great advances are made. Postponing inevitable protests.

new_direction

link: http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(13)60623-6/fulltext

The benefits and harms of breast cancer screening

On the basis of two 30 35-year-old randomised studies, the Independent UK Panel on Breast Cancer Screening1 concludes that there is 19% overdiagnosis when screening with mammography. This estimate is diluted and biased because of extensive screening in the control groups.2

Furthermore, detection rates and the level of overdiagnosis have increased 100% or more as the sensitivity of the technique has improved (ultrasound, double view, computer-assisted reading, and MRI). When screening was introduced in Sweden (1986 89) and in Norway (1996 97), we noted a 50% increase in invasive breast cancer.3, 4 Additionally, the increase in ductal carcinoma in situ was much larger than in the old trials.5 The total increase in diagnosis in Norway was 75%, and when women were no longer invited to screening, there was no incidence decline (figure). If only half of this 75% increase is overdiagnosis (ie, 37·5% overdiagnosis), then there should be no cancer after age 69 years.5 When comparing age-matched cohorts in Sweden and in Norway, we found that almost all of the incidence increase when screening was due to detection of lesions that normally would go into spontaneous regression.3, 4

Before screening started in Sweden, there was no incidence increase,3 and Norwegian breast cancer rates in unscreened age groups have been constant during 1991 2009.5 There is no underlying incidence increase.

The increase in Sweden came before women started using hormone-replacement therapy (HRT) and the increase was also 50% among women younger than 50 years who were not using HRT.3 Furthermore, after 2002, HRT use dropped 80% in Norway without any decline in the breast cancer incidence.5 HRT cannot explain the increase.