title: Reduced risk of oestrogen receptor positive breast cancer among peri- and post-menopausal women in Scotland following a striking decrease in use of hormone replacement therapy.
abstract: Many countries report a decline in breast cancer incidence among peri- and post-menopausal women following a decline in HRT prescribing. To investigate recent Scottish incidence trends, European age-standardised incidence rates from 1997 to 2005 were stratified by method of first detection, ER status and age group. We developed change point models of the annual age-specific cases for the peri- and post-menopausal age groups and ER status using Poisson regression. In Scotland all HRT categories together show a 32.4% increase in the number of items dispensed in 1993-2000 followed by a striking 61.8% decline by 2007. The incidence rates of screen-detected tumours increased gradually in the 50-64 and 65-74 age groups. For the older age group this increase accelerated after 2003 corresponding to an extension of the age range of screening. For ER positive tumours in the 50-64 age group, age-standardised rates increased 31.5% from 1997 to 2000, followed by a statistically significant decrease of 11.2% by 2005 (change in slope=-0.0943, P<0.0001). We conclude that an overall incidence in the 50-64 age group declined since 2000 reflecting the sudden fall in HRT dispensed items and is largely accounted for by the decrease in ER positive tumour incidence. A longer term decline in ER negative tumours for this age group was pre-existing and is unaffected by the collapse in HRT prescribing.
authors.affiliation: Information Services Division, NHS National Services Scotland, Gyle Square, 1 South Gyle Crescent, Edinburgh EH12 9EB, United Kingdom. Katharine.sharpe@nhs.net
authors.forename: Katharine H
authors.initials: KH
authors.lastname: Sharpe
authors.forename: Paula
authors.initials: P
authors.lastname: McClements
authors.forename: Douglas I
authors.initials: DI
authors.lastname: Clark
authors.forename: Joanne
authors.initials: J
authors.lastname: Collins
authors.forename: Anthea
authors.initials: A
authors.lastname: Springbett
authors.forename: David H
authors.initials: DH
authors.lastname: Brewster
mesh_terms: D000368:Aged; D001943:Breast Neoplasms / Q000737:chemistry / Q000453:epidemiology*; D005260:Female; D020249:Hormone Replacement Therapy / Q000009:adverse effects / Q000706:statistics & numerical data* / Q000639:trends; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D047648:Perimenopause; D016012:Poisson Distribution; D017698:Postmenopause; D011960:Receptors, Estrogen; D012307:Risk Factors; D012606:Scotland / Q000453:epidemiology
chemical_list: D011960:Receptors, Estrogen