Lung cancer. Coloured magnetic resonance imaging (MRI) scan of a coronal (frontal) section through a patient's chest, showing a malignant tumour (orange, upper right) in the left lung. Cancer cells divide rapidly and chaotically. They may clump to form tumours (as seen here), which invade and destroy surrounding tissues. Lung cancer causes a cough, chest pain, shortness of breath and weight loss. If the cancer has not spread (metastasised) to other tissues then the tumour may be removed surgically. Other treatments include chemotherapy (anti-cancer drugs) and radiotherapy.