Friday 20 January 2012
A drug regimen found to cut a women’s risk of dying from breast cancer gives a higher risk of carpal tunnel syndrome, but this can be managed and does not persist once treatment has finished, according to a paper published today in the Lancet Oncology.
Women diagnosed with early stage oestrogen receptor-positive (ER+ or hormone sensitive) breast cancer are often given drugs for five years after surgery to help prevent the disease coming back.
The 37-country Intergroup Exemestane Study (IES), which involved more than 4,700 women, has previously reported that women who were switched to exemestane after two to three years of tamoxifen were less likely to have had disease recurrence or to have died than women who stayed on tamoxifen for the whole five year period. However, more patients in the exemestane group reported musculoskeletal symptoms – which can also include bone fractures, joint or muscle pain - while being treated than those in the tamoxifen group (42.4% compared to 33.2%). In particular, around 2.8 per cent of patients in the exemestane group experienced carpal tunnel syndrome during treatment compared with 0.3 per cent of the tamoxifen group.
The Institute of Cancer Research and Imperial College London in the UK and Leiden University Medical Center in the Netherlands have today reported in more detail on these musculoskeletal side-effects.
Carpal tunnel syndrome occurs when a nerve in the wrist is compressed, leading to pain and muscle weakness in the fingers and hand. Patients who developed carpal tunnel syndrome in this study suffered it for six months on average. The majority of patients were successfully treated for this side-effect with surgery, and very few patients discontinued their treatment because of carpal tunnel syndrome. Rates of carpal tunnel syndrome in people who had completed treatment were very low, and there was no evidence of a difference in occurrence between the two groups.
Professor Judith Bliss, Director of the Clinical Trials and Statistics Unit at The Institute of Cancer Research (ICR-CTSU), says: “The rate of carpal tunnel syndrome was higher in women who switched to exemestane than in those treated only with tamoxifen. We found more than half of patients who developed this side-effect had surgery, but the vast majority were able to continue their treatment for breast cancer and did not experience carpal tunnel syndrome once their treatment had concluded.”
The trial was sponsored by Pfizer, and Cancer Research UK provided funding to the ICR-CTSU and Imperial College London’s Clinical Trials Unit – Cancer.
Martin Ledwick, Cancer Research UK’s head information nurse, said: “This gives clinicians more information with which to help patients make fully informed treatment decisions. It is worth noting that carpal tunnel syndrome is usually treated successfully and this needs to be considered when balancing severity of side effects against benefits of different treatment options.”
About 75 per cent of the 48,000 women diagnosed with breast cancer in the UK each year have an oestrogen receptor positive tumour, meaning that the hormone oestrogen is playing a role in cancer growth. Both tamoxifen and exemestane are hormone treatments: tamoxifen works by blocking the tumour’s ability to use oestrogen, while aromatase inhibitors like exemestane reduce the body's production of oestrogen.
Media Contact: ICR Science Communications Manager Jane Bunce on [email protected] on 0207 153 5106 or after hours 077217 47900
Notes to editors:
"Carpal tunnel syndrome and musculoskeletal symptoms in postmenopausal women with early breast cancer treated with exemestane or tamoxifen after 2—3 years of tamoxifen: a retrospective analysis of the Intergroup Exemestane Study" published in Lancet Oncology on January 20 2012.
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