Lung cancer diagnosis

How is lung cancer diagnosed?

If a routine physical examination reveals swollen lymph nodes above the collarbone, a mass in the abdomen, weak breathing, abnormal sounds in the lungs, or dullness when the chest is tapped, your doctor may suspect lung cancer. Sometimes it is symptoms such as coughing up blood, recurrent chest infections or unexplained weight loss that trigger concern. Some lung cancers produce abnormally high blood levels of certain hormones or substances such as calcium. If a person shows such evidence and no other cause is apparent, a doctor should consider lung cancer.  But often there are no signs or symptoms and it is only by chance that a lung cancer is discovered, for example when a chest X-ray is taken.

Lung cancer, which originates in the lungs, can also spread to other parts of the body, like distant bones or the brain. It may be first discovered in a distant location, but is still called lung cancer if there is evidence it started there.

Once lung cancer begins to cause symptoms, it is usually visible on an X-ray. Occasionally, lung cancer that has not yet begun to cause symptoms is spotted on a chest X-ray taken for another purpose. A CT scan of the chest may be ordered for a more detailed examination.

Though laboratory examinations of sputum or lung fluid may reveal fully developed cancer cells, diagnosis of lung cancer is usually confirmed through a lung biopsy. With the patient lightly anaesthetised, the doctor guides a thin, lighted tube through the nose and down the air passages to the site of the tumour, where a tiny tissue sample can be removed. If the biopsy confirms lung cancer, other tests will determine the type of cancer and how far it has spread. Nearby lymph nodes can be tested for cancer cells, while imaging techniques such as CT and MR scans and bone scans can detect cancer elsewhere in the body.

Because neither routine sampling of saliva and sputum, nor chest X-rays, have proved particularly effective in detecting small tumours characteristic of early lung cancer, the NHS does not run a mass screening programme for lung cancer. So stay vigilant for symptoms, especially if you smoke.