(colorectal cancer) Cancer that develops in the colon (the longest part of the large intestine) and/or the rectum (the last several inches of the large intestine before the anus).

(colorectal cancer) Colorectal cancer is cancer that develops in the tissues of the colon or rectum. Your colon and rectum are part of your digestive system: Your colon is the first and longest part of your large intestine. It absorbs water and some nutrients from foods. It also changes the leftover waste products into stool (poop).; Your rectum is the lower part of your large intestine. It's where your body stores stool. Cancer that begins in the colon is called colon cancer, and cancer that begins in the rectum is called rectal cancer. Cancer that affects either of these parts may also be called colorectal cancer. Colorectal cancer happens when there are changes in your genetic material (DNA). These changes are also called mutations or variants. Often, the genetic changes that lead to colorectal cancer happen during your lifetime and the exact cause is unknown. But certain genetic changes that raise your risk for colorectal cancer are inherited, meaning that you are born with them. Besides genetics, other factors, including your lifestyle and the environment, can affect your risk of colorectal cancer. Anyone can get colorectal cancer, but certain factors make you more likely to develop it: Being older; your risk of getting colorectal cancer increases as you age.; Having a personal or family history of colorectal cancer.; Having a history of adenomas. Adenomas are colorectal polyps (growths) that look abnormal under a microscope or are 1 centimeter or larger. Adenomas are not cancer, but they can sometimes turn into cancer over time.; Having a genetic syndrome such as familial adenomatous polyposis (FAP) or Lynch syndrome (hereditary non-polyposis colorectal cancer).; Having chronic ulcerative colitis or Crohn disease for 8 years or more.; Having three or more alcoholic drinks per day.; Smoking cigarettes.; Being Black; Black people have an increased risk of colorectal cancer and death from colorectal cancer compared to other races.; Having obesity. Colorectal cancer may not always cause symptoms, especially at first. If you do have symptoms, they could include: A change in bowel habits that lasts more than a few days, such as: Diarrhea; Constipation; Feeling that the bowel does not empty completely; Your stool is narrower or has a different shape than usual.; Blood (either bright red or very dark) in the stool; Frequent gas pains, bloating, fullness, or cramps; Weight loss for no known reason; Fatigue. Because colorectal cancer may not cause symptoms at first, it's important to have screening tests for colorectal cancer. Screening tests look for signs of a disease before you have any symptoms. They can help find cancer early, when it may be easier to treat. Most experts recommend that start screenings at 45 and continue until at least age 75. People over 75 and those who are at high risk should talk to their providers about how often you need screening and what type of test they should get. The types of tests include different stool tests and procedures such as colonoscopies and flexible sigmoidoscopy. Talk with your provider about how often you need screening and what type of test you should get. If you have symptoms that could be caused by colorectal cancer or if your screening test results are abnormal, you may need to have more tests to find out if you have cancer. Possible tests include: A physical exam.; A digital rectal exam. For this exam, your provider inserts a lubricated, gloved finger into your rectum...

A malignant epithelial neoplasm that arises from the colon or rectum and invades through the muscularis mucosa into the submucosa. The vast majority are adenocarcinomas.

Lynch syndrome is characterized by an increased risk for colorectal cancer (CRC) and cancers of the endometrium, ovary, stomach, small bowel, urinary tract, biliary tract, brain (usually glioblastoma), skin (sebaceous adenomas, sebaceous carcinomas, and keratoacanthomas), pancreas, and prostate. Cancer risks and age of onset vary depending on the associated gene. Several other cancer types have been reported to occur in individuals with Lynch syndrome (e.g., breast, sarcomas, adrenocortical carcinoma). However, the data are not sufficient to demonstrate that the risk of developing these cancers is increased in individuals with Lynch syndrome.

Colorectal cancer is extremely common. Symptoms include blood in the stool and change in bowel habits. Screening using one of several methods is recommended for appropriate populations. Diagnosis is by colonoscopy. Treatment is surgical resection and chemotherapy for nodal involvement.