Lung metastasis

Metastasis is the transfer of cancer from one organ or part of the body to another. Cancer cells are able to invade the bloodstream and end up virtually anywhere in the body. A lung metastasis is therefore a secondary cancer in the lung that has spread from somewhere else.

When metastasis occurs, the lungs are frequently the destination of cancer cells, and a lung metastasis is found in one third of all patients whose cancer proves to be fatal. It is often the discovery of a lung metastasis, as a result of investigating the causes of certain symptoms, that shows that the patient already has a tumour somewhere else in the body.

The lungs are organs the functions of which are closely linked with those of many other organs, such as in the transfer of oxygen and nutrients, but this leaves them vulnerable to secondary infections of many kinds coming from other organs. They are composed of sensitive tissue that is easily damaged. These two factors make metastasis to the lungs a common event.

The primary cancer can be virtually anywhere, but the cancers that most frequently spread to the lungs are those of the breast, colon, prostate and bladder. It is also possible for a lung metastasis to come from a primary lung cancer, but this is usually only after it has spread to another organ and then back to the lungs. A metastasis can be present in the lung in a dormant state long after the primary tumour has been removed and the patient has been thought to be clear of cancer.

Much research has been done to discover why cancers spread in this way. For example, research at the Howard Hughes Medical Institute in Chevy Chase, Maryland, has suggested that a group of four genes, working together, enables cancerous cells from breast tumours to escape into the bloodstream and cause lung metastases. Shutting off all four genes at the same time has had a dramatic effect on halting not only metastasis but also the growth of the original tumour. In all, the researchers have discovered 18 genes that make a contribution to metastasis, and they have also found that targeting the proteins produced by these genes, using drugs that are already on the market, could be effective in reducing metastasis.

Another possible breakthrough has been made at the Cold Spring Harbor

Laboratory, New York, where the cells have been identified that cause a dormant lung metastasis to become aggressive, often with fatal results. These are endothelial progenitor cells, or EPCs, and they are found in the bone marrow. They provide the switch that leads to blood vessel development within a tumour, and hence its growth. Knowing the mechanism involved is a huge step forward in devising treatments that could save many lives.

The symptoms of a lung metastasis include shortness of breath, chest pain, coughing, unexplained weight loss and general weakness, all of which can be symptoms of other conditions, some of them much less serious. It is also possible for there to be no symptoms at all, and for the metastasis to be revealed during other procedures, such as a chest x-ray for another purpose.

Treatment for a lung metastasis is usually chemotherapy, as surgical removal does not guarantee that all secondary growths have been treated. As the patient’s cancer is likely to be at an advanced stage, major surgery may not be advisable in terms of the patient’s general condition. However, surgery can be an option under certain circumstances, for example when there is a good chance that all the tumours have been detected and can be removed. As mentioned above, current research provides hope of new treatments becoming available in the foreseeable future.

© John Welford

Asthma

Asthma is a chronic disease (in other words, it lasts a long time) of the airways. It cannot be cured, and it can be fatal. However, there are plenty of Olympic athletes who suffer from it. It is an unpleasant disease to have, but it can be controlled.

In a person with asthma, the lining of the airways becomes inflamed and produces excess mucus, which narrows the airways. There may also be muscular contractions that make the condition worse.

The end result is that the patient finds it difficult to breathe, and may cough or make wheezing noises as the air tries to force its way through. The chest will feel tight during an attack. An episode can last for about an hour, or persist for a day or longer, especially if it is untreated. After the attack subsides, the airways return to their normal state and the sufferer feels perfectly OK.

Some people get an attack only once every week or so, whereas others can suffer daily attacks. In the worst cases, patients can suffer asthma symptoms for much of the day, every day, and their quality of life is affected very seriously. Night-time attacks are experienced by most sufferers, but again the frequency varies considerably from patient to patient. The frequency of attacks is not normally related to their severity; a very severe attack can be suffered by someone who only gets them rarely.

Asthma is a common complaint, without about 20 million of the current population of the United States having a diagnosis of it. It can begin at any age, but it is usual for it to start in childhood. In developed countries, around 15% of children of school age are likely to have asthma attacks of a greater or lesser severity. Although there is no cure for asthma, many children “grow out of it” as they get older.

In most people, asthma is a severe form of allergy, as the attacks are brought on by the presence of one or more “triggers” to which the patient is sensitive. However, asthma also tends to run in families, so there are probably genetic causes as well.

The substances to which the sufferer is allergic are typically such things as dust mites, animal fur and pollen. But attacks can also by triggered by tobacco smoke, bad air, perfumes and strong cooking smells.

Attacks can also arise from taking exercise, or viral infections.

It is therefore the case that asthma varies considerably from patient to patient, in terms of causes, triggers, frequency and severity of attacks. It is therefore vital that the individual’s condition be analysed carefully, so that the treatments are correct and the sufferer is able to adjust their lifestyle so as to make attacks as infrequent and mild as possible.

People who are liable to suffer an attack should always carry an inhaler with them. This delivers a shot of a relieving drug directly to the airways, acting very quickly to relax the muscles that are constricting the flow of air into the lungs. A typical drug for this purpose is salbutamol or terbutaline. Teachers of children with asthma need to be able to recognize the symptoms and make sure that a child can use an inhaler when they need to.

There are also inhalers that can be used on a daily basis to help prevent an attack. These are steroid-based and work by reducing the inflammation in the airways, thus making the chance of mucus blockage much less likely.

Tablets can be prescribed in addition to inhaler use, as a preventative measure.

Proper diagnosis of an asthmatic condition is necessary so that the correct treatment can be offered. Diagnosis includes measuring the rate of airflow into and out of the lungs, and testing for allergic reactions.

Apart from medication, treatment includes the avoidance of potential triggers and making lifestyle adjustments. For example, bedsheets may need to be changed more often than normal, and mattresses and pillows covered in material that is impermeable to dust mites. Carpets in bedrooms can harbour mites, and may need to be removed.

It cannot be denied that living with asthma is a thorough nuisance, but, with careful management, the symptoms can be controlled and the frequency and severity of attacks reduced to a minimum.

© John Welford