New prostate cancer treatment tested
Publication Date:23/07/2008
You may have read about a new treatment for prostate cancer, which has had promising results. Reports say it could save many thousands of lives every year. But the treatment is still being tested, and the research is at a very early stage. We take a closer look.
What do we know already?
Prostate cancer is the most common cancer to affect men in the UK. Most prostate cancers grow slowly, meaning that many men don't know they have cancer, and won't ever be affected by it. But some prostate cancers grow faster and spread to other organs or into the bones. Faster-growing prostate cancer can be life-threatening, and cancer that spreads to the bones can cause severe pain. In the UK, about 10,000 men die each year from prostate cancer.
There are several treatments for prostate cancer, including surgery to remove the tumour, hormone treatments to stop the tumour growing and radiotherapy to kill the cancer cells. Some men choose a wait-and-see approach, and don't have any treatment until the cancer starts to spread. Some men live for many years without having treatment for prostate cancer and have regular check-ups instead.
Some types of prostate cancer need a supply of male sex hormones, such as testosterone, in order to spread. Doctors have tried various treatments to block these hormones. Drugs can be used to block hormone production, and some men have surgery to remove their testicles, as the testicles make most of the body's supply of testosterone.
Hormone treatments work for some men, but for others, treatment doesn't block enough hormones to stop the tumour growing. The latest study looks at a new drug to block hormones, for men who hadn't been helped by existing treatments.
What does the new study say?
The study looked at a drug called abiraterone. It works by blocking a chemical in the body (an enzyme) that helps to make male sex hormones.
All the men in the study had advanced prostate cancer that had continued to grow despite other treatments.
Here's what the study found.
- Men with prostate cancer tend to have high levels of a chemical called PSA in their blood. For 14 of the 21 men in the study (66 percent), levels of this chemical dropped by nearly a third. In other studies, this kind of fall in PSA levels meant a better chance of surviving prostate cancer.
- At the start of the study, 11 of the men were getting pain because of their cancer. After treatment, 8 of these 11 (73 percent) found their pain improved. The men were able to stop or cut down on their painkillers.
- Eight men had tumours that could be seen on scans. After treatment, 5 of the 8 men (63 percent) had smaller tumours.
There were few serious side effects at any dose. The most common side-effects were low levels of potassium in the body and high blood pressure.
However, existing hormone treatments can cause some unpleasant side effects. Because of the drop in male hormones, some men get erection problems, grow breasts, get hot flushes, lose some hair or put on weight. The research on abiraterone hasn't looked at many people yet, so it's impossible to say how its side effects compare with current hormone treatments.
Where does the study come from?
The study was carried out by doctors at the Royal Marsden Hospital in Surrey. It was published in the Journal of Clinical Oncology, which is owned by the American Society of Oncology. It was paid for by a company called Cougar Biotechnology.
How reliable are the findings?
It's important to remember that this is an early study of abiraterone. It only included 21 people and all of them took the drug. The results might look promising, but we can't say how abiraterone compares to existing treatments. We can't even be certain that it's better than no treatment at all. We need to see good-quality, big studies that compare abiraterone with other prostate cancer treatments, or with a placebo (a dummy treatment used for comparison in medical trials).
This doesn't mean the researchers did a bad job. The study is a 'phase 1' study, which means it's the first time this drug has been properly tested in humans. Phase 1 trials are usually very small, because researchers want to know that the drug is safe and won't harm people, before they give it to large groups of people.
Bigger studies are already underway to find out whether abiraterone helps men with prostate cancer to live longer. But we won't know the results for two to three years. The drug won't be made available unless these studies show positive results.
What does this mean for me?
If you or someone you know has prostate cancer, you'll be interested in any new treatment that might help. The results of the study are encouraging, but it's much too early to say whether abiraterone will be a good treatment for prostate cancer.
Also, this drug is not likely to be the answer for all men with prostate cancer. Not all cancers react to hormones. Other types of treatment, like surgery or radiotherapy, may be better for some people. And for men with very slow-growing prostate cancer, no treatment may be needed.
Abiraterone is not yet available for patients, except for people taking part in clinical studies of the drug.
What should I do now?
There's no need to take any action as a result of this study.
If you're being treated for prostate cancer and you're interested in this study, you could ask your doctor about it. More studies are being carried out, and some people may be suitable to take part in the studies.
From:
Attard G, Reid AHM, Yap TA. Phase I clinical trial of a selective inhibitor of CYP17, abiraterone acetate, confirms that castration-resistant prostate cancer commonly remains hormone driven. Journal of Clinical Oncology. Published online 21 July 2008.
To find out more, read our information on prostate cancer.
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