Colorectal cancer, also known as colon cancer or rectal cancer depending on where it starts, is one of the most common types of cancer in both men and women. It usually begins as small, noncancerous (benign) clumps of cells called polyps that form on the inside of the colon. Over time, some of these polyps can become colorectal cancers. Here are some key points about colorectal cancer:

1. Risk Factors: Factors that may increase the risk of colorectal cancer include older age, African-American race, a personal history of colorectal cancer or polyps, inflammatory intestinal conditions, inherited syndromes that increase cancer risk, family history of colorectal cancer, low-fiber and high-fat diet, a sedentary lifestyle, diabetes, obesity, smoking, and alcohol.
2. Symptoms: Symptoms of colorectal cancer include a change in bowel habits, including diarrhea or constipation or a change in the consistency of stool, rectal bleeding or blood in the stool, persistent abdominal discomfort, a feeling that the bowel doesn't empty completely, weakness or fatigue, and unexplained weight loss.
3. Screening and Detection: Regular screening is one of the most powerful weapons for preventing colorectal cancer. Screenings can often find colorectal cancer early, when it's most likely to be treatable, or even prevent it by finding and removing precancerous polyps. Various tests are used for colorectal cancer screening, including colonoscopy, stool tests, and others.
4. Diagnosis: If colorectal cancer is suspected, a colonoscopy is usually performed, during which samples of any suspicious areas are biopsied. Imaging tests like CT scans, MRIs, and PET scans might also be used to help determine the extent of the cancer.
5. Staging: The stage of colorectal cancer ranges from I (1) through IV (4). The lower the number, the less the cancer has spread. A higher number, such as stage IV, means a more advanced cancer.
6. Treatment: Treatment options depend on the stage of cancer and can include surgery, chemotherapy, radiation therapy, targeted drug therapy, and immunotherapy. Surgery is the most common treatment for early-stage colon cancer.
7. Prognosis: The prognosis for colorectal cancer varies greatly depending on the cancer's size, location, and spread when it's diagnosed. Survival rates are higher when the cancer is detected at an early stage.
8. Prevention: Lifestyle changes can significantly reduce the risk of colorectal cancer. These include eating a variety of fruits, vegetables, and whole grains, drinking alcohol in moderation, quitting smoking, exercising most days of the week, and maintaining a healthy weight.
9. Research and Advances: Ongoing research in genetics, immunotherapy, and targeted therapy is improving the understanding and treatment of colorectal cancer, leading to more personalized and effective approaches.

Colorectal cancer is a major health concern, but increased awareness, screening, and advancements in treatment have improved outcomes and survival rates for many patients. Early detection remains key in the successful management of this disease.