title: HRT and breast cancer: impact on population risk and incidence.
abstract: This study has calculated the potential impact of hormone replacement therapy (HRT) on breast cancer incidence in Australia and has estimated how changes in prescribing HRT to women could affect this risk. The effects of HRT on breast cancer incidence was estimated using the attributable fraction technique with prevalence data derived from the 2001 Australian Health Survey and published rates of breast cancer relative risks from HRT use. In Australia, 12% of adult women were current HRT users and in 2001, 11783 breast cancers were reported. Of these, 1066 (9%) were potentially attributable to HRT. Restricting HRT use to women aged less than 65 years, ceasing HRT prescribing after 10 years or limiting combined oestrogen and progesterone HRT to five years (but otherwise keeping prescription levels to 2001 levels) may reduce the annual breast cancer caseload by 280 (2.4%), 555 (4.7%) or 674 (5.7%), respectively. In conclusion, this study has demonstrated that when HRT prevalence is relatively high, the effect on breast cancer incidence in the population will be significant. A small modification in HRT prescribing practices may impact breast cancer incidence in Australia with associated financial and health care provision implications.
authors.affiliation: New South Wales Breast Cancer Institute, University of Sydney, Westmead Hospital, P.O. Box 143, Westmead, NSW 2145, Australia.
authors.forename: Nathan J
authors.initials: NJ
authors.lastname: Coombs
authors.forename: Richard
authors.initials: R
authors.lastname: Taylor
authors.forename: Nicholas
authors.initials: N
authors.lastname: Wilcken
authors.forename: John
authors.initials: J
authors.lastname: Boyages
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D001315:Australia / Q000453:epidemiology; D001943:Breast Neoplasms / Q000139:chemically induced / Q000453:epidemiology*; D005260:Female; D020249:Hormone Replacement Therapy / Q000009:adverse effects* / Q000706:statistics & numerical data; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D015995:Prevalence