英国では毎年30,000人が乳ガンを発症するが、胸部に限局している場合は治療がしやすいが、転移すると難しくなる。転移のプロセスは十分に解明されていないが、最新の研究で、ストレスホルモン( norepinephrine and epinephrine)がガン細胞の転移能力を高める可能性がわかってきた。βブロッカーがガン細胞上のこのホルモンの受容体に付いて活性を阻害する可能性がある。
Page last updated at 12:47 GMT, Friday, 26 March 2010
Beta-blockers 'cut cancer spread'
Radiologist studying mammograms
A radiologist studies mammograms
Blood pressure drugs may be able to reduce the ability of breast cancer to spread around the body, researchers have told a European conference.
A joint UK and German study found that cancer patients taking beta-blockers had a lower risk of dying.
The drugs may block hormones that trigger the spread of cancer cells.
However, experts stressed that more evidence from bigger studies would be needed before the drug could be given as part of routine treatment.
We are very encouraged by these first results which have already shown that by using a well-established, safe and cost effective drug, we can take another step on the road towards targeted therapy in breast cancer
Dr Des Powe, Queen's Medical Centre
Breast cancer, which affects more than 30,000 people in the UK each year, is most easily tackled when tumours are confined to the breast only.
When cancer cells migrate to other parts of the body, and start growing, a process known as metastasis, the likelihood of successful treatment begins to fall.
The biological processes which trigger metastasis are still not fully understood.
The latest research, presented at the European Breast Cancer Conference in Barcelona, builds on earlier laboratory studies which suggest that the ability of cancer cells to increase in number and spread is boosted by the presence of stress hormones.
Beta-blockers attach themselves to the same receptors on cancer cells used by these hormones, potentially reducing their ability to stimulate the cell and trigger spread.
They are already taken by approximately two million people in the UK.
To test this theoretical cancer-fighting ability, Dr Des Powe, from Queen's Medical Centre, Nottingham, in collaboration with Professor Frank Entschladen from Witten University in Germany, looked at three groups of breast cancer patients, a total of 466 people.
The first group had high blood pressure, also called hypertension, and were taking beta-blockers, the second had high blood pressure, but were taking something different for it, while the third had no blood pressure problems.
In the 43 who were taking beta-blockers, there was a significant reduction in both cancer metastasis, and new tumours within the breast. Overall they had a 71% lower chance of dying from breast cancer compared with the other groups.
Dr Powe said: "It is reasonable to speculate, therefore, that some non-hypertensive women with breast cancer will respond favourably to beta-blocker treatment, though doses and side-effects would need to be investigated in clinical trials."
However, he said that the study was "relatively small" and its results would need to be reproduced in a larger group of patients.
"We are very encouraged by these first results which have already shown that by using a well-established, safe and cost effective drug, we can take another step on the road towards targeted therapy in breast cancer."
Meg McArthur, from Breakthrough Breast Cancer, welcomed the findings: "Although this is early stage research, these results show that beta blockers could play a role in reducing the risk of metastatic breast cancer. This is a positive step forward as it could potentially lead to survival improvements for people affected with this condition.
"However, as the study is quite small, we would like to see further research in this area."
NB: this will be the subject of a news briefing by Dr. Des Powe at 10.15 hrs CET on Friday 26 March [Room 128]
Beta-blockers help reduce metastasis and improve survival in breast cancer patients
Barcelona, Spain: Treatment with beta-blockers can help reduce the spread of cancer in patients with breast tumours, a researcher will tell the seventh European Breast Cancer Conference (EBCC7) in Barcelona today (Friday). In a controlled study, Dr. Des Powe, a senior healthcare research scientist at Queen’s Medical Centre, Nottingham University Hospital NHS Trust, Nottingham, UK, and his team found that the group of patients treated with beta-blockers showed a significant reduction in metastasis and better survival. The scientists believe that they are the first in the world to have investigated the effect of beta-blockers in breast cancer patients.
In collaboration with Professor Frank Entschladen’s group at Witten University, Germany, Dr. Powe looked at three groups of breast cancer patients: those who were already being treated for hypertension by beta-blockers, those whose hypertension was treated by other medications, and those who did not suffer from hypertension and were therefore not taking any treatment for it. Forty-three of the 466 patients were already taking beta-blockers and, in this group, there were significant reductions in both distant metastasis and local recurrence. They also had a 71% reduced risk of dying from breast cancer compared with the other groups.
“We were also able to study the presence of one receptor for beta-blockers, β2AR, as a potential biomarker for predicting clinical response to beta-blocker treatment,” says Dr. Powe, “but we did not find that this correlated directly to the outcome of treatment. We are currently looking at other target receptors as predictors of clinical outcome.”
Previous cell line laboratory studies have shown that beta-blockers work against various types of cancer because high levels of stress hormones in the tumour increase cell proliferation and migration (the movement of cells to other locations). “These effects are induced by the stress hormones norepinephrine and epinephrine acting on specific target receptors in a kind of lock and key fashion,” says Dr. Powe. “We sought to translate these laboratory findings into clinical research.”
Beta-blocker drugs bind to a specific kind of receptor to prevent the stress hormones from reaching their target; in cancer cells this prevents the hormones from stimulating and activating them. The researchers say that they are sure that their results are due to the effect of beta-blockers rather than a protective effect of hypertension per se.
“If that had been the case, we would have seen similar survival benefits in patients receiving other forms of treatment for hypertension,” says Dr. Powe, “but we did not. It is reasonable to speculate, therefore, that some non-hypertensive women with breast cancer will respond favourably to beta-blocker treatment, though doses and side effects would need to be investigated in clinical trials. We also need to look at whether beta-blockers could be given as a supplementary therapy with existing breast cancer treatment.”
This finding may assist treatment in two ways, say the researchers: it appears to slow down tumour growth and could also be used to target those patients who have an increased risk of developing secondary cancers.
“Our first study is relatively small, and we now intend to validate it in a larger group,” says Dr. Powe. “We will be looking for funding and collaborators to test the effectiveness of beta-blocker treatment on patients diagnosed with breast cancer. We are very encouraged by these first results which have already shown that by using a well-established, safe, and cost-effective drug, we can take another step on the road to targeted therapy in breast cancer.”
Abstract no: 445, Friday 15.30 hrs, Rooms 115+11
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