Treatments such as chemotherapy and hormonal therapy have greatly improved the survival of women diagnosed with early breast cancer, scientists said on Friday.
An analysis of 194 trials involving 145,000 women showed both therapies combined can halve the 15-year risk of death from the disease, which is the most common cancer in women.
“The standard chemotherapy and hormonal therapy that have long been used to prevent breast cancer recurrence not only have an effect on 5-year survival but they have a long-lasting effect on 15-year survival,” said Professor Sarah Darby, of the Radcliffe Infirmary, in Oxford, England.
“The benefits of chemotherapy and hormonal therapy can be added to each other,” she added in an interview.
More than a million women worldwide each year are diagnosed with breast cancer. Surgery will remove the cancer and radiotherapy is given to kill any residual cells in the breast.
Chemotherapy and tamoxifen, a hormone therapy for estrogen-sensitive cancers, are often recommended as extra treatment if appropriate, to stop the disease coming back.
The study, reported in The Lancet medical journal, analyzed the impact of treatments on women involved in clinical trials that began before 1995.
It did not include new treatments such as aromatase inhibitors, which studies have shown may be more effective than tamoxifen, or drugs such as taxanes.“
“What we have got now is very good. It is better than people ever realized,” said Darby, adding that there have been massive decreases in breast cancer mortality rates since the 1990s.
Darby and her colleagues found that for women of all ages with early hormone-sensitive cancer, taking tamoxifen for five years could reduce their breast cancer death rate over the next 10-15 years by a third.
For middle-aged women, combining tamoxifen with chemotherapy halved the death rate.
“This is the largest follow-up study ever done in women with early breast cancer. It shows that we are making great progress in treating cancer increasingly effectively,” said Professor John Toy, of the charity Cancer Research UK, in a statement.
In a commentary on the analysis, Karen Gelmon of the British Columbia Cancer Agency in Vancouver, Canada described the findings as impressive.
She said the survival curves suggest that the therapies could cure a proportion of women with early-stage breast cancer, rather than simply delay recurrence of the disease.