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82 Effect of a quarter century of adjuvant therapy and mammographic screening on breast cancer mortality in the state of victoria, australia
  1. Robert Burton1,
  2. Christopher Stephenson2
  1. 1Monash University Melbourne Australia, Melbourne, Australia
  2. 2Deakin University, Geelong, Australia

Abstract

Objective The Early Breast Cancer Triallist Collaborative Group have demonstrated that post-operative endocrine and chemo-therapy (adjuvant therapy) can cure many women with early operable (pTNM stages 1 and 2:1/2) breast cancer (EBC). Mammographic screening can also reduce breast cancer mortality, but must down-stage breast cancer from advanced/incurable to EBC with available therapy to directly reduce mortality. The impact of adjuvant therapy versus mammographic screening on breast cancer mortality has not been reported for any population. Therefore our objective was to analyse data available from the State population of Victoria, Australia, which was exposed to both mammographic screening and adjuvant therapy in order to examine their differential effects on breast cancer mortality.

Methods Data from four Victoria, Australia State population based surveys of breast cancer management 1986–1999, Victorian Cancer Registry breast cancer incidence, mortality and stage at diagnosis 1982–2013 and the Victorian component of the free national mammographic screening program-BreastScreen 1992–2007 were analysed for associations between mortality trends, uptake of adjuvant therapy and down-staging by mammographic screening.

Results Breast cancer crude mortality declined by 30% between 1994 and 2013 and by 1999 74% of all Victorian women with EBC had commenced adjuvant endocrine therapy and 72% of pre-menopausal and 29% of postmenopausal women with EBC had commenced adjuvant chemotherapy. Advanced breast cancer (pTNM stages 3 and 4:3/4) crude incidence increased by 74% between 1995 and 2013, proof that screening was not down-staging breast cancer in Victoria (2.8 million women in 2011). The age standardize incidence of SEER advanced stage breast cancer (distant disease) for women in NSW, Australia’s most populous State (3.6 million women in 2011–32% of Australia’s women), increased by 67% from 4.3 to 7.2 per 100,000 women between 1988–1995 and 2006–2012. Crude Australian pTNM stages 3/4 incidences were calculated from published data for both 1995 and 2011as 13.3 and 21.7, per 100,000 women respectively, a 63% increase in advanced breast cancer crude incidence in Australia between 1995 and 2011. Therefore mammographic screening had also failed to downstage breast cancer nationally, so BreastScreen could not have directly reduced Australian breast cancer mortality. There was a persistent increase in EBC incidence in Victoria above the 1986–1990 trend from 1995 onwards, which is evidence of screening mammographic over-diagnosis of EBC that would never have become clinically apparent.

Conclusions There is no population mortality benefit from a quarter centuries mammographic screening in Victoria, NSW and Australia as a whole. Adjuvant endocrine and chemotherapy uptake can account for the entire Victorian State female breast cancer mortality decline. Therefore, mammographic screening in Australia has been all harms and no benefits. This is compounded by external beam radiotherapy for small breast cancers, over-diagnosed and preferentially detected by screening mammography, damaging the heart, lungs and adjacent tissues, thereby increasing all-cause mortality.

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