Lung Cancer


Each organ in the human body is made up of millions of tiny cells. These cells only survive for a short period. They then die and are replaced by new cells. This process of cell death and growth happens on a daily basis. It is usually very tightly controlled to stop excessive cell growth. When cells in an organ "escape" this normal control mechanism, they can multiply in great numbers, to form a cancerous growth called a tumour. When this growth takes place in the lung, we call it lung cancer. In most cases of cancer in the body, we do not know what sets off this abnormal cell growth. However, in the case of lung cancer, tobacco smoking is the major cause.


Studies have shown that the vast majority of people with lung cancer are, or have been, tobacco smokers. Tobacco contains hundreds of harmful substances called carcinogens, i.e. they are known to cause cancer. Only a small number of smokers get lung cancer. The reasons for this are not known. It does seem that the longer you smoke, and the more cigarettes per day you smoke, the more likely you are to develop the illness. Lung cancer can also be caused by a heavy exposure to someone else's smoke, so called passive smoking. Rarely, lung cancer can develop in someone who has only smoked for a short time, or never smoked at all. This is unusual. Lung cancer can be caused by heavy exposure to other harmful inhaled substances, such as asbestos dust. The major cause is tobacco smoke, however. People most commonly present with lung cancer in their 60's. However, it does occur in younger and older age groups. It is seen more often in men, but is becoming more common in females. Lung cancer will soon overtake breast cancer as the most common cause of cancer in women. This makes the high rates of smoking among young women all the more worrying.


One of the major problems with lung cancer is that, by the time it starts to cause symptoms, it is usually quite advanced. In the early stages of the illness, there are usually no symptoms. The first symptom is usually development of a cough, or worsening of a pre-existing cough. The patient may notice streaks of blood in the phlegm. Shortness of breath, weight loss and fatigue are usually seen in the later stages of the illness. Pain is unusual in lung cancer. This is unless the cancer invades bone, such as the ribs or spine. Headache or confusion may be seen if the cancer has invaded the brain. Sometimes, the cancer is seen on a chest x-ray done for other reasons, with the person having no chest symptoms. In this instance, the cancer may be picked up at an early stage.


Usually, the cancer is seen as an abnormal shadow on a chest x-ray. The next step is to perform a CT scan. This is a special x-ray which gives detailed pictures of the chest and the abdomen. The CT scan shows the lung cancer in more detail, and also checks if the cancer has spread elsewhere (e.g. other lung or the liver). The best way to confirm the diagnosis is to get a piece of tissue from the suspected cancer. This is called a biopsy. It is important to confirm that the abnormal lung shadow is cancer, and to determine the type of lung cancer present. This is because some types of cancer grow quicker than others. Also, there are different treatments for the various types. To get the sample of tissue (or biopsy), a small tube is passed down the nose or mouth, into your lungs. This is done while you are gently sedated with an injection. This procedure is called a bronchoscopy. It can be done as a day case. The procedure is painless, and safe. The very rare complications that can happen will be explained. If the tissue samples from the lung do not show any cancer, but cancer is still suspected, then another procedure, called a CT biopsy, may be needed. This involves taking a piece of lung tissue through the skin on the front or back of the chest with a small needle. You will be given local anaesthetic to numb the skin. The procedure should be fairly painless and will be explained to you by your doctor. Sometimes, an operation under general anaesthetic is needed to get the biopsy sample. Other tests that might be required include a PET scan (to exclude spread of the cancer to other parts of the body); a bone scan (if spread to the bones is suspected), and a brain scan if spread to the brain is suspected.


Broadly speaking, there are 2 types of lung cancer. These are called non-small cell cancer and small cell cancer, based on their appearance under the microscope. Non-small cell cancer is much more common. It tends to grow more slowly. Surgery or radiotherapy is the usual treatment for this. Small cell cancer is less common and grows more quickly. It has almost always spread beyond the lung at the time of diagnosis. Surgery is usually not an option. It is usually treated with chemotherapy (see below).


The treatment of lung cancer depends on the type of cancer and the how much it has spread in the body. The general health and fitness of the patient is also taken into account when treatment is being decided. You may be offered an operation. This is if the cancer is confined to one lung, and you are deemed fit for surgery. The operation involves removing a whole lung, or part of the lung. Breathing tests are done before the operation. This is to make sure that you will have enough breathing capacity in the remaining lungs. Radiotherapy is a very useful treatment for some types of lung cancer. This is very good at shrinking the tumour and/or controlling symptoms. It involves sitting in front of a machine that brings high doses of x-rays to the chest. The skin of the chest is usually marked before starting treatment. This allows the xrays to be delivered to a certain area of the lungs.
Radiotherapy can also be very useful for controlling pain due to spread of the cancer to the bones. It can also be delivered to the head if the cancer has spread to the brain. Each course of radiotherapy is called a cycle. Usually several cycles are given over the course of a few days or weeks. The response to radiotherapy is not immediate. It usually takes a few weeks to work. Side effects from radiotherapy are few. You may feel a little tired after treatment. You may also notice a slight discomfort on the skin similar to sunburn.
Chemotherapy is a form of treatment that is very effective for some types of lung cancer, especially small cell cancer. This involves giving medication which makes cancer in the body shrink or disappear. The medication is usually given in the hospital. It is in the form of injections through a "drip". Sometimes, chemotherapy can be given in tablet form. Nowadays, chemotherapy has fewer side effects which will all be explained to you by your doctor in great detail (oncologist or cancer specialist). Sometimes, the different treatments will be combined together, if the doctor feels that it is appropriate. In some cases, no immediate treatment is given. This is especially if the cancer is small or slow-growing. A "wait-andsee" approach is taken, which means observing the cancer's growth over time.
The outcome of lung cancer treatment varies widely. Some people do extremely well, and others not so well. A positive outlook can go a long way. People with advanced disease can sometimes do very well. Every case is taken on its merits. Doctors do not like to predict how a person will respond to treatment. This is because everyone responds differently. Even if there is no cure for a person's cancer, modern drugs are very effective at controlling symptoms. This means that no-one with lung cancer, nowadays, should be suffering.