Breast cancer drug ‘still benefits patients’ for years after they stop taking it

THE medicine anastrozole should be the “drug of choice” for postmenopausal women at high risk of breast cancer, new research shows.

A study found that the drug – which is available on the NHS – slashed the risk of breast cancer in half compared with a placebo, and offered protection for years after women stopped taking it.

Researchers said most women should now take anastrozole (also known as Arimidex) rather than another popular drug, tamoxifen, due to its enhanced benefits.

However, they warned that a number of women are missing out because some doctors are reluctant to prescribe it. The National Institute for Health and Care Excellence (Nice) currently recommends a fiveyear course of anastrozole for postmenopausal women at high or moderate risk of breast cancer unless they have severe osteoporosis.

It also says clinicians should consider offering it to women at moderate risk of breast cancer.

Women at high risk who have not been through the menopause should continue to be offered tamoxifen, the Nice guideline says.

Women are deemed to be high-risk if close family members have suffered from breast cancer, particularly at an early age.

The new research, published in The Lancet medical journal, included 3,864 women who were split into two groups.

The first group was given anastrozole for five years, while the second group received a placebo drug.

After a follow-up of 12 years, including five years on the drug, women taking anastrozole had a 49 pre cent reduced risk of breast cancer compared with the placebo (85 cases compared with 165).

The reduced risk was biggest in the first five years of taking the drug (35 cases versus 89) but was still significant after five years (50 versus 76 cases). The overall number of deaths was small, and no significant difference in deaths was observed overall.

The researchers concluded: “The large 61% reduction in breast cancer incidence in the first five years has been maintained in subsequent follow-up to 12 years.

“The significant 36% reduction during post-treatment follow-up was not significantly smaller than during treatment, and still greater than that observed for tamoxifen, which has produced a roughly constant 29% reduction for 20 years.

“The number needed to treat to prevent one breast cancer during the first 12 years of follow-up was 29, which compares favourably with the 58 needed for tamoxifen at that time.”

The latest study also found that anastrozole did not have the longterm side-effects associated with tamoxifen - including endometrial cancer. There was no increased risk of heart disease or fractures either.

Both anastrozole and tamoxifen are hormonal therapies which are taken in tablet form.

Professor Jack Cuzick, from Queen Mary University of London, who led the study, said the data was so strong that the switch should be made to offering women anastrozole as a firstchoice treatment.