About colorectal cancer
Colorectal cancer (CRC) is a common and potentially lethal disease. It is estimated that approximately 145,600 new cases of large bowel cancer are diagnosed annually in the United States, including approximately 101,420 colon and 44,180 rectal cancers. it remains the third most common cause of cancer death in the United States in women, and the second leading cause of death in men.
Typical symptoms/signs associated with CRC include hematochezia or melena, abdominal pain, otherwise unexplained iron deficiency anemia, and/or a change in bowel habits. Less common presenting symptoms include abdominal distention, and/or nausea and vomiting, which may be indicators of obstruction.
In a retrospective cohort of over 29,000 patients referred by their general practitioners over a 22-year period, presenting symptoms in the 1,626 who were eventually diagnosed with bowel cancer included:
Colorectal cancer symptoms
- Change in bowel habits, which was the most common symptom (74%)
- Rectal bleeding in combination with change in bowel habits, which was the most common symptom combination (51% of all cancers and 71% of those presenting with rectal bleeding)
- Rectal mass (24.5%) or abdominal mass (12.5%)
- Iron deficiency anemia (9.6%)
- Abdominal pain as a single symptom, which was the least common symptom presentation (3.8%)
The diagnosis of a colorectal cancer (CRC) is made by histologic examination of a biopsy that is usually obtained during lower gastrointestinal tract endoscopy or from a surgical specimen. Histopathologically, the majority of cancers arising in the colon and rectum are adenocarcinomas.
CRC may be suspected from one or more of the symptoms and signs described above or may be asymptomatic. Once a CRC is suspected, the next test can be a colonoscopy or computed tomography (CT) colonography.
Many conditions cause signs or symptoms that are similar to colorectal adenocarcinomas including other malignancies as well as benign lesions such as hemorrhoids, diverticulitis, infection, or inflammatory bowel disease. The differentiation of which generally requires biopsy and histologic evaluation. Rare malignancies other than adenocarcinomas that are primary to the large bowel include Kaposi sarcoma (KS), lymphomas, carcinoid (well-differentiated neuroendocrine) tumors, and metastases from other primary cancers.
There is no diagnostic role for routine laboratory testing in screening or staging CRC. However, serum carcinoembryonic antigen (CEA) levels should be obtained preoperatively and postoperatively in patients with demonstrated CRC to aid surgical treatment planning and assessment of prognosis.
In cancer care, different types of doctors often work together to create a patient’s overall treatment plan that usually includes or combines different types of treatments. This is called a multidisciplinary team. For colorectal cancer this generally includes a surgeon, medical oncologist, radiation oncologist, and a gastroenterologist.