Small-cell carcinoma, also called small-cell lung cancer and oat cell cancer, is a highly malignant form of cancer made up of mutated epithelial cells. It usually appears in the lungs, but can appear in the cervix and pancreas. It's primary cause is smoking, but it can arise from second-hand smoke and other noxious smoke.
Small-cell is the most malignant form of lung cancer and spreads rapidly. If it is caught before it spreads out of the chest, the odds of survival are somewhat better, but even at this stage, only about 20% of patients survive beyond five years. Once the disease spreads beyond the chest, the prognosis is poor and death is imminent.