13: Cancer
By the end of this chapter you will be able to:
- Explain how cancer begins and spreads.
- Describe the difference between benign and malignant tumors.
- Compare incidence and risk factors for common types of cancer.
- Identify ways to prevent cancer
How does cancer start?
How does cancer spread through the body?
What are the most common types of cancer?
How do I know if I have cancer?
The human body is composed of trillions of cells and every cell has a specific purpose. Cells provide structure for the body, take in nutrients from food, convert those nutrients into energy, and carry out specialized functions. When cells become damaged or die, the body makes new cells to replace them. For example, the epidermis of our skin continually makes new skin cells and we shed off old dead skin cells. Unfortunately, sometimes the cells in our body change and they begin to grow and divide when they shouldn’t, this is known as Cancer, all cancers begin with a change in just one microscopic cell.
Cancer is the 2nd leading cause of death in the U.S. after cardiovascular disease. In the United States in 2019, 1,752,735 new cancer cases were reported and 599,589 people died of cancer. For every 100,000 people, 439 new cancer cases were reported and 146 people died of cancer. In 2022 in the U.S., there will be an estimated 1,918,030 new cancer cases and 609,360 cancer deaths.
Cancer has a major impact on society in the United States and across the world. Thankfully, in the United States, the likelihood of dying from cancer has dropped steadily since the 1990s. Five-year survival rates for some cancers, such as breast, prostate, and thyroid cancers, now are 90 percent or better and the 5-year survival rate for all cancers combined is currently about 67 percent.
The information in this chapter comes primarily from two Public Domain sources: