Women fighting breast cancer have better long-term survival rates using a newer drug compared with Tamoxifen, once the standard NHS treatment.
A new study shows letrozole cut the risk of cancer returning by one-fifth, and patients were 21 per cent less likely to die.
The findings confirm that women with early breast cancer taking letrozole, an aromatase inhibitor (AI), for five years after surgery live longer without the disease, compared with Tamoxifen.
‘AIs’ were approved five years ago for postmenopausal women being treated on the NHS but some patients take Tamoxifen initially and switch to an AI drug within two to three years.
New research found women using letrozole, also known as Femara, for the entire five-year period are more likely to survive.
The drop in risk of death was 21 per cent, while there was a 20 per cent reduction in risk of their breast cancer coming back, says a U.S. led study published in The Lancet Oncology.
It is the latest analysis of a trial of 8,000 women carried out in 27 countries including the UK, which assigned women to either letrazole or Tamoxifen or each drug in sequence.
After eight years of follow-ups, women given letrazole alone fared best compared with women taking Tamoxifen alone.
Taking the drugs in turn did not significantly cut the risk of relapse or death compared with letrazole alone.
Lead author Meredith Regan, from the International Breast Cancer Study Group Statistical Center at the Dana-Farber Cancer Institute in Boston, said: ‘This updated analysis shows that letrazole offers long-term protection over Tamoxifen in these patients.’
Around 48,000 British women develop breast cancer each year, including 35,000 after the menopause, and Tamoxifen has been routinely used for 20 years to cut recurrence rates.
AI drugs shut down the body’s supply of oestrogen altogether, while Tamoxifen works by blocking the effect of oestrogen on cancer cells.
These drugs work in women only after the menopause and where breast cells are sensitive to oestrogen – up to four in five cases.
The Government’s rationing watchdog has approved three aromatase inhibitors (AI) – Aromasin, Arimidex and Femara – alongside Tamoxifen and primary care trusts are expected to fund them.
Experts say the latest findings mean AI drugs should now be used in preference to Tamoxifen.
Although AIs can cause problems with bone density, Tamoxifen has a four-fold higher risk of leading to hysterectomy following womb disorders. AIs also cause fewer serious side effects than Tamoxifen such as blood clots and stroke.