The Diagnosis of Lung Cancer

Many patients find that they have lung cancer either because they present symptoms such as persistent coughing and wheezing, sometimes coughing up blood or pain the chest and stomach. This usually prompts further investigation of the chest, typically calling for an x-ray (which may also occur as part of a routine health check) and the testing of sputum samples.

At this point more investigations will be called for dependent upon the results.

Detailed Diagnosis

The purpose of a chest radiograph or x-ray, is to detect enlarged lymph nodes in the chest or the existence of a mass in the lungs. More advanced techniques can be used to provide much more detailed information and include the following:

CAT Scan or CT Scan - a CT Scan is a computer assisted examination which provides a cross-sectional image of the body under examination;

MRI Scan - a Magnetic Resonance Imaging (MRI) scan uses hydrogen ions within the patient's body which respond to magnetic fields when they are applied to the body or in this case, the chest. A computer then uses the results to create a chest image which allows for precise location of any mass which has been detected and whether it involves the lungs;

Bronchoscopy - this involves an examination of the airways (the windpipe and lung branches) and is usually conducted by a pulmonologist ( a physician who specializes in respiratory diseases). The examination may involve the taking of a swab from these areas or a biopsy (the removal of a tissue sample);

Needle Biopsy - a physician inserts a needle using the results of a CT Scan to guide where the needle, so a sample of tissue may be removed from the mass which has been detected; the tissue samples obtained are then "smeared" on a microscope slide and examined by a histopathologist to detect whether the cells are cancerous; and

Bone Scan - this test may be undertaken to check whether any cancer cells have spread (known as "metastasized") to the bones from the original tumor.

A technological advancement is the CT/PET fusion imaging scan - this diagnostic tool uses an injected sugar solution which contains a radioactive element to highlight any cancerous mass. Cancer tumors are very fast growing and use a lot of energy so they rapidly absorb the sugar solution which is accumulates around and within the tumor. When a scan is then performed, the concentration of the radioactive sugar is detected and provides the location and detail of the cancer tumor. It should be borne in mind that there are other tissues which will cause the sugar solution to accumulate such as a bacterial infection, so even this test is not conclusive.

Once lung cancer has been diagnosed, the team of oncology physicians treating the patient will review the results to assess the treatment options for the lung cancer and to check whether any spread of the disease has occurred to other parts of the body. Where it is found the disease has not spread to other parts of the body, then a surgical inspection may take place to assess the disease in detail around the lungs, heart, windpipe and tissues of the chest. In addition, extensive blood tests will take place to look for cancer "markers" which are usually proteins that are associated with the development of lung cancer.