Dr. Daniel - The Cancer Directory

The only way to diagnose cancer definitively is to test a sample of abnormal cells from the site of the tumour. The usual way of doing this is to obtain a biopsy, or a small tissue sample, under either a local or general anaesthetic, depending on the site of the tumour.

Cancer has no specific symptoms – it depends on where the tumour is, how big it is, which structure it is invading and whether it has spread to other parts of the body. A patient with lung cancer, for example, may have a cough with or without blood or phlegm, or a persistent chest infection that does not respond to antibiotics. The usual symptom of breast cancer is a lump in the breast, although it may well have spread by the time it can be detected this way. If it has spread, then its symptoms will depend on the site of the metastases – in the lungs, it may mimic a lung tumour; in the liver, a liver tumour, and so on.

Because cancer produces so many different types of symptoms which can be mistaken for minor illnesses, there may be a period of several weeks with repeated visits to the GP before the symptoms are taken seriously. The best rule of thumb is that any progressing symptom that does not disappear after two to four weeks should be further investigated. Usually, this involves being referred to a hospital where the investigations can be done rapidly.

If cancer is suspected, there are two important requirements: to do a biopsy to find out exactly what type of cells have gone wrong and, therefore, how best to treat them; and to ‘stage’ the disease to find out how far the disease has spread as this, too, dramatically affects not only the optimal treatment, but also the likely outcome.

The tests to determine the site and stage of the cancer include:

• Biopsy, to study a piece of tissue thought to be cancerous – the definitive way to make the diagnosis

• Blood tests, to check for anaemia, bone-marrow function, liver and kidney function, and search for tumour markers – substances produced by cancer cells and detectable in the blood, thereby alerting doctors to the presence or spread of cancer

• Plain X-rays, to provide information about various parts of the body

• Contrast X-rays, injecting or ingesting a radiopaque substance to increase what can be seen on the X-ray

• CT (computed tomography) scans, to provide detailed information about the structure of various internal organs

• MRI (magnetic resonance imaging), a powerful imaging technique based on magnetic field shifts in the body

• Bone and liver scans, to show areas of dysfunction in the bone and the liver that may be due to the spread of a cancer.

Determining how far a cancer has spread is a critical starting point before deciding on treatment. There are several systems available and this often causes confusion, even among doctors.

One of the most commonly used staging systems is the TNM system, developed by a committee of the International Union Against Cancer. Here, the letter T stands for ‘tumour’, with T 1referring to a small tumour and T 4referring to a very large one.

The N stands for ‘nodes’, the lymph nodes draining the organ in which the tumour is found. Enlarged nodes containing growing tumours are classified as N 1or N 2depending on their site and number.

The M stands for ‘metastasis’ (spread) and is either present (M 1) or absent (M 0).

Other staging systems are often simpler. Early-stage disease may be called stage 1 whereas late-stage disease, or more advanced cancer, is then stage 4. Different criteria may be used for cancer at different sites of the body, so ask your consultant to explain exactly what the staging means for your type of cancer. A person with disease that has not spread is likely to have a better outcome than a patient whose disease has already left its primary site. This is because a localized tumour is more likely to be cured or removed altogether by either surgery or radiotherapy.

The grade of a cancer, determined by the pathologist by looking at the cancer cells through a microscope, is also useful in predicting the outcome of a cancer. A high-grade tumour contains very abnormal cells, which have mutated greatly, grown rapidly and often spread throughout the body. This is also referred to as ‘poorly differentiated’. At the other end of the spectrum are low-grade tumours, which can look similar to the tissue from which they have been derived and are referred to as ‘well differentiated’. Such tumours grow more slowly and are less likely to spread quickly. The outlook is usually better for low-grade tumours, but there is a paradox. High-grade aggressive tumours are often more sensitive to chemotherapy as the chemicals work best against the most rapidly dividing cells in the body. Unfortunately though, rapidly growing cells can continue to evolve and can become resistant to specific drugs rather rapidly, too.

It is also possible to have varying opinions as to the grade of a tumour among pathologists. So, if you are in any doubt, or the pathology seems uncertain, ask for a second opinion from another pathologist.

Cancer that develops in the body away from the site of the original tumour is called a ‘secondary cancer’ or a metastasis. These may be found at the time of diagnosis or they may develop later on. If secondaries appear, it can often be a more severe blow than the original diagnosis.

Cancer can spread around the body by:

• invading local tissues

• entering the lymphatic system and lymph nodes

• entering the bloodstream and travelling to distant sites

• direct infiltration of a neighbouring organ.

Some cancers have a predictable route of spread and favour certain organs for secondaries whereas others are more unpredictable.

Working out the chances of your treatment being successful is difficult because the response to treatment varies considerably from one person to another. However, the three essentials that guide your outcome are the:

• primary site of the tumour

• stage of the tumour

• grade of the tumour.

Another important piece of information is how you respond to treatment. There are four types of response and you will hear the following terms being used:

• A ‘complete response’ is where the tumour has disappeared completely

• A ‘partial response’ is where it has shrunk to half its size, as visualized by X-rays or some other quantifiable measure

• ‘Stable disease’ means that the disease is not growing

• ‘Progressive disease’ means that growth is continuing despite treatment.

Following surgery, if the primary tumour has been completely removed, then technically the patient has had a complete response. With chemotherapy, it is vital to assess response early on in the course of treatment to make sure there will be benefit and that it is worthwhile to continue the treatment.

The best way to assess the cure rate for a particular type of cancer is to look at survival curves compared with those who do not have cancer. If 100 patients with lung cancer are treated and we look at their survival curve, it will be clear that they do less well than those of the same age without lung cancer. The definition of ‘cure’ means that the survival rate of a treated group of patients is the same as those of similar age and gender who did not have cancer.