Q&A: MR SENTHIL NATHAN
Consultant urologist and robotic surgery pioneer on ClinicSafe, a major development in the treatment of prostate cancer
Interview: Viel Richardson
Portrait: Christopher L Proctor
What is the prostate?
It is a gland, the main function of which is related to reproduction, by secreting enzymes that help the sperm to swim. With age, it grows bigger, and that can cause problems. The incidence of having an enlarged prostate is directly proportional to your age. At 60 years old, you have a 40 per cent chance, at 80 years old it is 80 per cent, and if you get your telegram from the Queen it is almost certain you will have an enlarged prostate. Prostate cancer is also age-related. The longer you live, the higher the chance of developing prostate cancer.
Do you always have to treat a cancer if it develops?
Actually, no. Sometimes prostate cancer does not grow or grows very slowly and only requires monitoring. In these cases, the man will live a perfectly normal life for decades with no ill effects. In other cases, the cancer is more aggressive and will need to be treated. If the disease is diagnosed early, it is very treatable. Ninety per cent of those caught early can be treated effectively without reducing the person’s life expectancy. Unfortunately, there is about 10 per cent chance that even if caught early, it will continue to spread despite our best efforts.
What are the treatments available for prostate cancer and what are the potential side effects?
There are three gold standard treatments for prostate cancer: radiotherapy (external beam therapy); brachytherapy (injecting radioactive material), which attacks the cancer itself; or surgery to remove the cancerous tissue or the whole prostate. All three can have side effects due to nerve damage in the nearby area. Erection is controlled by the cavernous nerves, which lead to vascular changes that cause erection. There is a 30-50 per cent chance that you will lose your erections after any of these treatments because the nerves that control the blood supply to the penis have been removed or damaged. Another side effect is ‘dry orgasms’—when the man reaches climax, the sensation of pleasure will be the same, but little or no semen will emerge. This means natural conception is no longer possible, so if the patient wants to have children some form of IVF treatment will be necessary. Another major potential impact is incontinence of urine, where the patient loses some or all of his ability to control his bladder.
Why are the cavernous nerves likely to be removed or damaged?
This is because they are often very close to where the cancer tends to occur in the prostate. In the standard procedure, when removing enough tissue to ensure we remove all the cancer we unfortunately have to sacrifice these nerves, which will have a significant impact on the patient.
Is this what inspired you to develop ClinicSafe?
In part, yes. A procedure designed to protect nerves emerging from the peri-prostatic nerve plexus had already been developed in Germany, patented in America under the name NeuroSafe. But I believed it could be significantly improved upon in terms of the accuracy in mapping tumours, thereby improving the eventual outcome for the patient. So, I assembled a team here at The London Clinic to develop this, and ClinicSafe was the result.
How does ClinicSafe work?
The real step forward with ClinicSafe was the introduction of MRI scans. Using both MRI scans and biopsies, we build up a very accurate picture of where the cancer is and can determine if there is a possibility of leaving the nerves intact. If there is, we cut along a path in the narrow gap between the nerves and the cancerous tissue. It is a tricky procedure and undertaking it needs a level of precision that can better be achieved using robotic surgery techniques. However, with this approach there is a potential risk that some cancer cells may be left behind, so we check this with what we call a ‘frozen section’.
What is a frozen section?
Within about five minutes of being removed, the prostate will arrive in a pathology lab, where a waiting pathologist will freeze it using a cryostat machine and cut it into very thin slices. The pathologist then examines the slices to look for any cancerous cells in the area of the sample nearest to the cancer. They are very well briefed before the operation, with access to all the MRI scans, maps of the tumour and any other information they need. It means that between 15-30 minutes after receiving the sample, they can tell us whether they see any cancerous cells close to the margins. If there are none, we know we have removed all of the cancer and do not have to sacrifice the nerve. If, however, the pathologist sees some cancer in the margins, we continue the operation, removing extra tissue and therefore sacrificing the nerves.
How effective is the technique at protecting the nerves?
It’s extremely successful in this regard. This is still in its infancy, but of the first 31 patients who underwent this procedure, only three required partial removal of the nerves on one side, as opposed to sacrificing all the nerves on both sides, as would normally have been the treatment in their cases. Statistical analysis has shown that if a new treatment has a 15-20 per cent improvement over the standard operation, this is something that the NHS should adopt. As you can see, we are a long way past this threshold. As we speak, the NHS is testing the procedure with a two-year trial consisting of 600 patients.
That must be great news for the patients.
Yes, it is really gratifying to talk to men who emerge with everything intact and working. Going into the process, the potential side effects are a real worry for them. In fact, they are one of the things that prevent some men, especially young ones, seeking treatment. But there are benefits beyond those to the patient. One of the biggest costs of a loss of erectile function is prescriptions for medication like Viagra, which allow the man to maintain his sex life. This is a real financial burden on the NHS.
The other major advantage is control of continence. Saving the nerves removes the need for the patient to wear incontinence pants for the rest of his life, another huge cost. For me, though this procedure is generally talked about as a way of saving the ability to achieve an erection, I believe avoiding incontinence is equally important.
Is the technique applicable elsewhere?
Recently, I have been working on the idea of using the technique elsewhere on the prostate. At present, it is only used on tissue from the sides of the gland, as this is often where the early cancer is found. However, often we have advanced cancer towards the top of the prostate adjoining the sphincter muscles, or at the back of the prostate next to the bladder. Generally, we err on the safe side and remove more tissue. If you’re operating at the top, you can damage the sphincter muscles—and the same with bladder muscles if you are operating at the back. This surgical technique presents a real opportunity to save more muscle tissue in these areas. We have just launched it here at The London Clinic—the first time this has been done anywhere in the world.
What about away from the prostate?
Any solid organ where there is cancer may benefit. Once you have taken out the least amount of healthy tissue you think you need to, this technique can check whether you have excised all the cancer cells. The benefits across several types of surgery could be quite significant.
You mentioned that this can only be done with robotic surgery techniques.
You need the magnification, dexterity and precision of movement that robotic technology provides. The problem is that the prostate sits behind the pelvic bone, so you cannot see very much in an open operation. Quite often, prostate operations are done by feel. But with surgical robots you have cameras in situ sending a view of the target area onto a high-quality 3D screen. With this view, you can use the robotic instruments to make extremely precise and delicate incisions.
Are there innovations in robotics surgery taking place that could improve the procedure?
Some real advances are being made in terms of what we can do with the robotic telescope when it is in situ. With the appropriate attachments, the robotic telescope itself will be able to determine whether there is cancer present and where it sits. We may be able to inject dyes, which will clearly differentiate cancerous cells from healthy tissue. We already have the kit to do this at The London Clinic but are still working on the dyes. If we inject radionucleotides and attach a radio nuclear counter to the telescope, it could tell us exactly where the cancer is, because cancerous cells absorb radionucleotides to a far greater degree than the healthy tissue. Also, at some point we will be able to add a microscope with the same magnification of those the pathologists now use to look for cancerous cells. This means we could be able to check for cancerous cells in situ. The direction of travel is in the area of what you can do with the equipment once you have it in place. There are still some difficult challenges to be overcome with all these advances, but real progress is being made.
What would your silver bullet against prostate cancer be?
As I have mentioned, prostate cancer is a disease very closely linked to age. We are going to see more and more prostate problems as more people are living to a greater age. My silver bullet would be a vaccine that we could give to men when they reach 50 that would protect them for the next 20 years, then repeat the dose at 70, and so forth. A vaccination would be wonderful, both in terms of people’s quality of life and in the enormous sums of money it would save the NHS. But we are a very long way from that at the moment.