Colorectal cancer, also referred to as colon or rectal cancer, starts in the colon or the rectum. The colon, rectum and anus are part of the large intestine, a long, tube-like organ that processes food and water and helps to pass waste material out of the body. Most colorectal cancers start when cells in the inner lining of the colon or rectum grow out of control. These abnormal growths are called polyps. Over time, some polyps can become cancerous. There are different types of polyps, however, and not all polyps become cancer. Colorectal cancer is the third most common form of the disease and the second leading cause of cancer death in the U.S. Overall, 1 in 23 men (4.3%) and 1 in 25 women (4%) are at risk of developing colorectal cancer in their lifetime. Thanks to screenings and lifestyle changes, the rate of people, especially older adults, being diagnosed with colorectal cancers has dropped in recent decades. However, rates have been increasing in younger people since the mid-1990s.