Women who have stopped taking hormone therapy may still have an increased risk of cancer, research reveals.
The Women's Health Initiative trial of estrogen plus progestin hormone therapy in 16,000 women was stopped in 2002 when data indicated an increased risk of breast cancer and no overall benefit.
A follow up trial in some 15,000 women from the first study has since found that women who took hormone therapy still have an increased risk of breast cancer compared with other women three years later.
The rate of cardiovascular events and risk of fractures, however, was comparable between women who took hormone therapy and those who did not.
The researchers said: "This analysis of delayed and sustained health benefits and risks following randomised allocation to hormone therapy versus placebo adds new information to inform the optimal use of postmenopausal hormone therapy."
They hope this study will help to increase the optimal use of HRT.