Sadly, most lung cancer is diagnosed too late for curative treatment to be possible. In over half of people with lung cancer the disease has already spread (metastasised) at the time of diagnosis.
Early diagnosis is difficult because many of the common symptoms of lung cancer are similar to those of smokers' lung (chronic obstructive pulmonary disease or COPD).
In addition to this, most lung cancer patients will also have COPD because both conditions are mainly caused by smoking. However, only 1 or 2 per cent of COPD patients will go on to develop lung cancer.
The first investigation is a chest X-ray. If a lung tumour is present, it needs to be at least a centimetre in diameter to be detectable by an ordinary X-ray. However, by the time a tumour has reached this size the original cell which became cancerous has divided (or doubled) 36 times. As death usually results after 40 such cell divisions, it is clear that lung cancer is a disease that is usually detected late in its natural course.
Some simple blood tests and further examinations may also be carried out.
Bronchoscopy is direct inspection of the inside of the breathing tubes with a thin fibre-optic instrument using local anaesthetic and is the best test for tumors in the main bronchi (air passages) in the centre of the chest.
Depending on the site of the cancer, a biopsy will be obtained either by a bronchoscopy or a needle biopsy. Needle biopsy is better for cancers near the periphery of the lungs (ie closer to the ribs than the centre of the chest), beyond the reach of the bronchoscope.
Usually, a sample of sputum the material coughed up from the respiratory tract will also be examined for cancer cells and this can avoid the need for biopsy.
ACT scan provides more information about how much the tumur may have spread.
There are three main types of lung cancer, based on their appearance when examined under the microscope by a pathologist :
- small cell carcinoma
- squamous cell carcinoma
- adenocarcinoma.
It is important to know which type of cancer a patient has because small cell cancers respond best to chemotherapy (anti-cancer medicines) whereas the other types (often referred to collectively as non-small cell cancer) are better treated with surgery or radiotherapy (X-ray treatment). The pathologist therefore needs a small tissue sample (biopsy) to examine. This will confirm that the diagnosis of suspected cancer is definitely correct and show which type of cell is involved.
The above information thankfully comes from the netdoctor.co.uk at the following link.
