New findings published in today's* (Friday 18 September) Lancet show that treating breast cancer with cell-killing drugs ("chemotherapy") improves long-term survival even if the cancer has not already spread to the local lymph glands. These benefits of chemotherapy are substantial for women aged under 50 at diagnosis, but survival is also improved for women in their 50s and 60s.
Even after successful surgery, breast cancer cells may remain undetected in the body. There are two main ways of treating these. One is hormonal therapy: for example, tamoxifen can be used to block hormone receptors on the cancer cells and so interfere with their growth. The other way is to use a cocktail of drugs to kill the cancer cells ("chemotherapy").
In the largest ever randomised study of chemotherapy for cancer, an international collaboration organised by the Imperial Cancer Research Fund's Clinical Trial Service Unit at Oxford University, followed 18,000 women with breast cancer.
Among women aged under 50 whose cancer had already spread to the local lymph glands at the time of surgery ("node-positive"), some months of chemotherapy typically prevented about 11 deaths during the next 10 years for every 100 women treated. But, among younger women with no evidence of disease spread, the benefits of chemotherapy were also substantial - about 7 fewer deaths per 100 treated. Chemotherapy produced a small, but real, improvement in survival - of about 2-3 lives saved per 100 - for women in their 50s and 60s whose cancer was either node-positive or node-negative.
Professor Rory Collins from Oxford University said: "We already knew that chemotherapy improves the chances of survival for a young woman with breast cancer which has spread to the local lymph glands. Now we know that this treatment is beneficial even if the cancer appears to be confined to her breast."
The study shows that, even if tamoxifen is to be given, chemotherapy produces additional benefit. Moreover, chemotherapy improves survival among women whose breast cancer is not hormone-sensitive, for whom there is as yet no clear evidence of benefit with tamoxifen.
The collaboration brought together detailed information from 47 randomised studies conducted over the past two decades around the world. There was no evidence of any survival advantage from using more than about 3-6 months of chemotherapy.
Dr Michael Clarke, of the Imperial Cancer Research Fund's Oxford Unit and the study coordinator, said: "This huge study provides uniquely reliable evidence about the effects of chemotherapy. In terms of recurrence and survival, the balance of the long-term benefits and risks favours some months of chemotherapy for a wide range of women with early breast cancer."
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* Polychemotherapy for early breast cancer: an overview of the randomised
trials. Early Breast Cancer Trialists' Collaborative Group. Lancet 19 September
1998
Breast Cancer Awareness Month
One in 12 women in the UK will get breast cancer at some time in their lives - nearly 32,500 new cases every year. Breast cancer is the most common cancer in women in the UK.
The Imperial Cancer Research Fund is working hard to find new answers to breast cancer and currently spends more than £5 million a year on research into the disease. Along with other organisations concerned with the breast cancer, Imperial Cancer is dedicating October to raising awareness of, and further funds for, vital research into the disease.
Imperial Cancer Research Fund - Background Brief
The Imperial Cancer Research Fund is dedicated to the understanding, prevention, treatment and cure of all forms of cancer. Its 1,000 scientists and doctors are at the forefront of the worldwide effort to defeat the disease. The charity relies almost totally on voluntary funding to carry out its vital work.
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Journal
The Lancet