Abiraterone uses a different method to block the chemicals in the body, writes Thomas Lynch
Q There was a lot of publicity last week about a new drug for prostate cancer. It was in a lot of the papers and on the news. Can you tell me about this new drug?
A The drug which you refer to is called Abiraterone and results from a clinical trial on 21 patients were published online in the medical literature. The results have also been presented at a recent cancer meeting in the United States.
One of the treatments for more advanced prostate cancer is hormonal manipulation, which involves blocking the production of testosterone by the testicles. Testosterone is often considered like a fertilizer for the prostate and prostate cancer and when the production of testosterone by the testicles is blocked then the growth of the tumour will be reduced.
Some prostate cancers are resistant to this type of hormonal manipulation or may develop this resistance while on treatment. This trial confirms that castration-resistant prostate cancer commonly remains hormone driven.
Abiraterone uses a different method from conventional treatment to block the chemicals in the body, which form testosterone. The researchers found that the tumour itself can sometimes produce the hormone so any treatment needs to be directed at the production in all areas of the body including the testicles.
The results of this study report the outcome of only 21 men who were treated with this new drug. The drug appeared to be well tolerated and showed a favourable response.
Patients have been followed up for over two and a half years but it is not known yet whether it will improve survival. Further studies will be required to answer this question and these clinical trials should start in early 2009.
The "phase 3" trials will compare this drug to a placebo or another standard treatment for advanced prostate cancer. Two groups of men with prostate cancer will be investigated: those receiving the drug and those on placebo.
This type of trial is called a double blind trial where neither the doctor nor patient knows which medication they are receiving until the end of the trial.
This allows for a non-biased comparison to be made. It is very important to have this information before introducing this drug into clinical practice.
The early results are sufficiently encouraging to investigate this drug further hence the trial. It must be stressed that this drug will not be available in any country outside of a clinical trial setting until the results of such trials are known.
Q I am a 34-year-old male and I have recently noticed that my legs get tired very easily. I have large veins visible on my legs and a rash, which can be very itchy. These symptoms have been present for the past six months and I was wondering what I should do?
A You are describing the appearance of varicose veins and the associated tiredness commonly associated with them. The itchy area is most likely to be an area of eczema, which is quite common in patients with varicose veins. It is otherwise called venous or varicose eczema.
The eczema can easily be treated with a steroid cream and support stockings. However, the underlying condition (your veins) will need to be dealt with if you are to solve the problems in the long term.
The underlying cause of varicose veins is leaky valves in the veins in your leg.
Normally the valves in the veins allow blood to flow in the direction of the foot to the heart but in people with varicose veins these valves don't function properly. This results in backflow of blood and increased pressure within the veins, which then fill with blood and become dilated.
You should consult your GP who is likely to refer you to a vascular surgeon. An ultrasound scan of your legs will be performed which will demonstrate where the "leaky valves" are.
The most common sites of these leaky valves are in the groin and at the back of the knee. These are the areas where the superficial veins draining the legs join the deep veins. Not all people with veins need surgery.
The options available are to wear graded compression stockings, which will keep your veins under control, but never actually get rid of them. Other options include injections, conventional surgery or to have them treated using keyhole techniques.
During conventional surgery a small cut is made in the groin or behind the knee and the junction between the superficial and deep veins is identified and tied off. When the groin is involved the superficial vein is then commonly stripped to below the level of the knee. In addition, multiple small incis- ions may be made in the skin to treat other prominent veins.
Treating your varicose veins with surgery is relatively safe. Wound infections occur infrequently and can be treated with antibiotics. In about 15 per cent of patients, a nerve that runs down the inside of the leg can get bruised during surgery resulting in an area of tingling or numbness on the inside of the ankle joint. This sensation generally passes within six weeks. Newer keyhole techniques are gaining popularity but are not universally available.
This technique involves the passage of a wire and sheath into the incompetent vein from the knee or lower calf. A laser or radio-frequency probe is then passed into the vein allowing it to be sealed and occluded. This is usually carried out as a day case under a local anaesthetic.
Patients often ask if there are any long-term problems associated with the removal or occlusion of veins in the legs. The answer to this is no, as most of the blood in the legs go through the deep veins (which are not interfered with) and, as the veins that are being removed are not functioning properly, they will not be missed.
This weekly column is edited by Thomas Lynch, consultant urological surgeon, St James's Hospital, Dublin with a contribution from Mr Prakash Madhavan, consultant vascular surgeon, St James's Hospital, Dublin