Colorectal cancer natural history

To view the natural history of familial adenomatous polyposis (FAP), click here
To view the natural history of hereditary nonpolyposis colorectal cancer (HNPCC), click here

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Saarah T. Alkhairy, M.D.; Elliot B. Tapper, M.D.; Roukoz A. Karam, M.D.[2]

The progression from an adenomatous polyp to colorectal cancer may take 10-15 years. Complications may arise if the cancer is not eradicated or from the treatment itself. Complications include intestinal obstruction, gastrointestinal bleeding, metastasis, cancer recurrence, radiation therapy adverse effects, chemotherapy adverse effects, post-surgical complications, metachronous colon cancer, and death. The 5 year survival rates depend upon the stage of colorectal cancer.

• Colorectal cancer usually arises from a precursor lesion, the adenomatous polyp.
• The progression from an adenomatous polyp to colorectal cancer may take 10-15 years.
• The symptoms of colorectal cancer usually develop in the 6th decade of life, and start with symptoms such as change in bowel habits, hematochezia or bleeding per rectum, abdominal cramps or discomfort, rectal pain, tenesmus, and/or diminished caliber of stools.
• Constitutional symptoms such as nausea/vomiting, unexplained weight loss, unexplained loss of appetite, weakness, fatigue, dizziness may develop to suggest colorectal cancer.
• If the disease advances and spreads to other organs, the patient may present with dyspnea, cough with blood-stained sputum, persistent pain or discomfort in the chest, swelling in hands/feet, itchiness, jaundice, and/or dark-colored urine.^[1]
• Patients with early-onset colorectal cancer more commonly present with rectal bleeding, abdominal pain, and change in bowel habits and are more frequently diagnosed at an advanced stage compared with older patients.^[2]

Common complications of colorectal cancer include:^[3]

• Intestinal obstruction
• Intestinal perforation
• Fistula formation
• Gastrointestinal bleeding
• Metastasis
  • Usually in the liver and lungs but may occur in other sites
• Cancer recurrence
  • Local: site of the original tumor
  • Regional: in lymph nodes near the primary tumor
  • Distal: in another part of the body
• radiation therapy adverse effects including skin discoloration, skin burns, headache, fatigue, hair loss, nausea, vomiting, and/or confusion
• chemotherapy adverse effects including hair loss, fatigue, weakness, nausea, vomiting, risk of infection, and/or diarrhea
• Death

Depending on the extent of the tumor at the time of diagnosis, the prognosis may vary. However, the prognosis is generally regarded as poor.

The 5 year survival rate at diagnosis of colon cancer:^[4]

The 5 year survival rate at diagnosis of rectal cancer:^[4]

CEA level may also be directly related to the prognosis of disease, since its concentration correlates with the bulk of tumor tissue.

Poor prognostic factors of patients with hepatic metastasis include the following:

• Synchronous (diagnosed simultaneously) liver and primary colorectal tumors
• A short time between detecting the primary cancer and subsequent development of liver metastasis
• Multiple metastatic lesions
• Large-sized metastatic lesions, which can be measured by a high concentration of carcino-embryonic antigen (CEA)

Early-onset colorectal cancer patients often have distinct tumor biology and psychosocial challenges compared with later-onset disease despite similar treatment approaches.^[5]

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