Interior of the cecum and lower end of ascending colon with the ileocecal valve labeled as colic valve. Endoscopic image of cecum with arrow pointing to ileocecal valve in foreground.
Lung cancer is a malignant tumour that starts in the cells of the lung. Malignant means that it can spread, or metastasize, to other parts of the body. When cancer starts in lung cells, it is called primary lung cancer. The lung is part of the respiratory system. You use your lungs when you breathe.
Two main types of lung cancer exist: small-cell lung cancer (SCLC, also called oat cell cancer) and non-small-cell lung cancer (NSCLC). 1  Small-cell lung cancer grows rapidly.The time from the development of symptoms to diagnosis is usually 90 days or less.  Small-cell lung cancer spreads quickly.