Excised section of cancerous human lung, showing rounded deposits of tumour (left, white areas), and widespread cigarette tar deposits (sooty stains). Cancer of the bronchus, more commonly known as lung cancer, is strongly associated with cigarette smoking and exposure to industrial air pollutants. Unfortunately, it is one type of cancer which is least amenable to treatment. Early stage diagnosis is difficult, when no symptoms are present. At the time of diagnosis (usually by chest X-ray), the tumour is often well-established & has metastasised, that is, spread to other organs such as the liver, spine and brain.