Cancer is characterized by uncontrolled growth and spread of abnormal cells. If left untreated, cancer can result in death. The document discusses several types of cancer including lung cancer, the leading cause of cancer death, and colon cancer, the second most common cancer. It also covers cancer statistics, risk factors, screening, treatment milestones, and specific cancers like lung and colon cancer. Preventable lifestyle factors contribute to nearly 1/3 of cancer deaths in the US. Early detection through screening improves diagnosis and survival rates.