Some of the most recent innovations in medical science may help in the diagnosis and treatment of cancer as well as heart and lung disease. Dr Muiris Houston, Medical Correspondent, looks to the future
Medicine is in a constant state of flux. Research breakthroughs eventually become part of medical practice. Some replace previous treatments; many others complement existing approaches to disease.
In the 15 years since I qualified, some medical specialities have become almost unrecognisable. Cancer treatment has moved forward in leaps and bounds. Radiology, and the methods used to make a diagnosis in a non-invasive way, have changed radically. Medical Resonance Imaging (MRI) techniques, even at an experimental level, simply did not feature when I was a medical student.
Soon we will have robotics - the use of a machine as a remote extension of the surgeon - helping to make minimally invasive surgery the norm. The Da Vinci surgical system makes use of a console unit at which the surgeon sits and a surgical arm unit which holds and manipulates the detachable surgical instruments. These tiny electronically controlled "wrists" duplicate hand movements at the site of the operation, allowing even more precision and eliminating natural tremor.
So, what are some of the latest developments in three key areas of medicine? Below are a sample of some of the most recent breakthroughs in heart and lung disease and cancer diagnosis.
Heart disease
Much has been written about gene therapy and its potential to change the face of healthcare. One such breakthrough, announced at a recent American Heart Association Conference, involves injecting patients who have coronary artery disease with a gene that stimulates the growth of new blood vessels in the heart.
Coronary heart disease leads to angina and causes heart attacks; the standard surgical treatment is either to carry out a bypass procedure or to use a balloon, inserted into the clogged artery, to compress the debris which is causing the blockage.
Now, doctors in San Diego and Boston have reported on the benefits of VEGF-1, which controls the production of a protein called vascular endotheial growth factor. By injecting the gene directly into the heart, they have stimulated the growth of new coronary blood vessels.
Both trials were small-scale affairs, with no more than 30 patients in each. None the less, the results offer hope to thousands of people with severe cardiac disease. The majority of those injected with the new gene reported a drop in the average number of angina attacks from 56 a week to four.
Not only was there an improvement in their quality of life, but also the 20-25 per cent death rate of patients with severe coronary artery disease was also significantly reduced.
The new breakthrough is considered "very exciting" by cardiologists. However, it is early days yet, and it will need the proof of much larger trials, involving thousands of people, before VEGF-1 is introduced into everyday use.
Another variation on the theme of non-surgical heart bypass is research from the biomedical engineering department of the University of Michigan, which proposes the use of a biodegradable "scaffold" to secrete growth factors such as VEGF into damaged blood vessels. The polymer scaffold could be removed once the timed release of the growth factors has been completed. This research is still at a pre-clinical phase; however, it is another sign of the possibilities of developing a less invasive alternative to heart bypass procedures.
New treatments for lung disease
Chronic obstructive airways disease is a hugely disabling condition which primarily affects smokers, especially later in life. With an ageing population and the increasing prevalence of smoking among women, the disease is still associated with a high death rate.
One of the features of chronic lung disease - emphysema - is that the lungs become overexpanded. As a result of this increased lung volume, their ability to function adequately is impaired. Carbon dioxide is retained rather than being transferred out of the body; and oxygen levels are lower than they should be. This has considerable knock-on effects for the person's well-being.
Surgery to reduce lung volume has attracted considerable attention from doctors and patients alike. It involves taking away wedge-shaped sections of the most severely diseased portion of the lung. The idea is to reduce overall lung volume by 20 to 30 per cent, with an accompanying improvement in carbon dioxide and oxygen exchange in the remainder. So far, two small trials have shown some benefit in quality of life; what is not yet clear is whether these gains are long-term, or whether the new procedure is safe for people with the severest form of emphysema.
Asthma is one of the commonest respiratory diseases - it affects 275,000 people in the Republic. Many new asthma drugs are being developed. Some are aimed at modulating the immune system; an antibody against immunoglobulin E, which plays a central role in the allergic response which can trigger an asthmatic attack, is close to being marketed. Research so far shows that the new therapy offers the possibility of reducing the dose of inhaled steroids while achieving an improvement in asthma symptoms.
Cancer
While the ultimate goal in combating cancer must be prevention, early detection of tumours (at a point where cure is possible), is the next best thing.
In women, cervical cancer is usually a slow-growing cancer, picked up by pap smear screening which has been the accepted test for many years.
This technique involves the use of a wooden spatula to scrape cells from the neck of the womb - they are then smeared onto a glass slide before being transported to a laboratory for analysis.
A new form of test takes the sample using a brush, which is then immersed in liquid rather than spread on a slide. It has the distinct advantage of allowing analysis for the presence of human papilloma virus (HPV) in the cells. HPV has been linked to the development of cervical cancer.
The use of the new technique could revolutionise the screening process. At present, many women get "borderline" results and have to be re-tested six or 12 months later.
Another development in the pipeline is an invention by an Australian gynaecologist. The "Truescan" is a pen-sized probe which emits a series of light frequencies and low-energy pulses. When placed in contact with the cervix, the optical and electrical sensors at its tip measure the response of the tissues, which is then analysed by computer.
Because normal and abnormal cells respond differently to stimuli, the computer can categorise tissue as normal or abnormal using a pattern-recognition system.
The new device has already been tested on more than 8,000 women, who report that the two-minute test is more comfortable than having a traditional smear taken. They also appreciate the immediate availability of the results. Trials are continuing, with the prospect of the new device becoming the standard test for cervical cancer in a GP's surgery.
For women with a high risk of breast cancer, an experimental procedure that retrieves cells from the milk ducts of the breast may help guide them in difficult treatment decisions.
A recent study in the Journal of the National Cancer Institute described the results of a study of 500 women who were at high risk of developing a breast tumour, either because of family history or a previous cancer in the opposite breast. Suspicious cells were found in one quarter of women tested.
While the test will never be applicable to all women, it looks as if it will be a useful adjunct for those faced with a very high risk of developing breast cancer.
Mouth cancer, while not as common as that of breast, lung and colon, tends to be diagnosed very late. So the development of a simple mouthwash to help dentists identify the disease is a welcome one.
The new test uses a solution of tolonium chloride (Oratest), which selectively stains cancer cells a deep blue colour. Used in conjunction with a soft-tissue examination of the mouth, the dye can detect barely visible lesions and pre-cancerous cells. Patients with suspicious lesions are then referred onwards for a biopsy and tissue analysis; tests so far suggest that 10 per cent of positive stains require further treatment.
These are just some of the recent advances in certain medical specialities. I hope to write about innovations in medicine again, so if readers come across new advances - while abroad, for example - I would be grateful to hear about them at the email address below.