MedWire News: The incidence of invasive breast cancer in peri- and postmenopausal women fell in Scotland following a striking decrease in the use of hormone replacement therapy (HRT), research shows.
“Many countries report a decline in breast cancer incidence among peri- and postmenopausal women following a decline in HRT prescribing,” explain Katharine Sharpe (NHS National Services Scotland, Edinburgh, UK) and colleagues.
To investigate recent Scottish incidence trends, Sharpe and team stratified European age-standardized incidence rates from 1997 to 2005 by method of first detection, estrogen receptor (ER) status ,and age group (50–64 and 65–74 years), reflecting changes in breast screening invitation and focusing on those age groups most likely to be taking HRT.
The researchers found that HRT prescriptions increased by 32.4% between 1993 and 2000, and then fell by a striking 61.8% by 2007.
The incidence rates of screen-detected tumors increased gradually in both age groups. Among the women aged 65–74 years, this increase accelerated after 2003 corresponding to an extension of the age range for screening.
In the younger age group, age-standardized rates of ER-positive tumors increased by 31.5% between 1997 and 2000, and then decreased by a significant 11.2% by 2005. ER-negative breast cancer rates fell by 44.3% from 1997 to 2005, while the incidence of tumors with unknown ER status fell by 35.7% over the same period
The researchers conclude that the decrease in the overall incidence of invasive breast cancer among women aged 50–64 years since the year 2000 reflects the sudden fall in HRT use.
They add: “The longer term decline in ER-negative tumors for this age group was pre-existing and is unaffected by the collapse in HRT prescribing.”
The study findings are published in the European Journal of Cancer.
MedWire (www.medwire-news.md) is an independent clinical news service provided by Current Medicine Group, a trading division of Springer Healthcare Limited. © Springer Healthcare Ltd; 2010
Free abstract
