Symptoms of colorectal cancer typically include rectal bleeding and anemia which are sometimes associated with weight loss and changes in bowel habits.
Most colorectal cancer occurs due to lifestyle and increasing age with only a minority of cases associated with underlying genetic disorders. It typically starts in the lining of the bowel and if left untreated, can grow into the muscle layers underneath, and then through the bowel wall. Screening is effective at decreasing the chance of dying from colorectal cancer and is recommended starting at the age of 50 and continuing until a person is 75 years old. Localized bowel cancer is usually diagnosed through sigmoidoscopy orcolonoscopy.
Cancers that are confined within the wall of the colon are often curable with surgery while cancer that has spread widely around the body is usually not curable and management then focuses on extending the person’s life via chemotherapy and improving quality of life. Colorectal cancer is the third most commonly diagnosed cancer in the world,
The treatment of colorectal cancer depends on how advanced it is. When colorectal cancer is caught early surgery can be curative. However, when it is detected at later stages (metastases are present), this is less likely and treatment is often directed more at extending life and keeping people comfortable.
For people with localized cancer the preferred treatment is complete surgical removal with the attempt of achieving a cure. This can either be done by an open laparotomy or sometimes laparoscopically. If there are only a few metastases in the liver or lungs they may also be removed. Sometimes chemotherapy is used before surgery to shrink the cancer before attempting to remove it. The two most common sites of recurrence if it occurs is in the liver and lungs.
Chemotherapy may be used in addition to surgery in certain cases as adjuvant therapy. If cancer has entered the lymph nodes adding the chemotherapy agents fluorouracil, orcapecitabine increases life expectancy. If the lymph nodes do not contain cancer the benefits of chemotherapy are controversial. If the cancer is widely metastatic or unresectable, treatment is then palliative. Typically in this case a couple of different chemotherapy medications are used. Chemotherapy drugs may include combinations of agents includingfluorouracil, capecitabine, UFT, leucovorin, irinotecan, or oxaliplatin.
While a combination of radiation and chemotherapy may be useful for rectal cancer, its use in colon cancer is not routine due to the sensitivity of the bowels to radiation.
In people with incurable colorectal cancer, palliative care can be considered for improving quality of life. Surgical options may include non-curative surgical removal of some of the cancer tissue, bypassing part of the intestines, or stent placement. These procedures can be considered to improve symptoms and reduce complications such as bleeding from the tumor, abdominal pain and intestinal obstruction. Non-operative methods of symptomatic treatment include radiation therapy to decrease tumor size as well as pain medications.