The symptoms of colon cancer in early stage are ofen mild or subtle, which are unnoticeable with patients and easily misdiagnosed. Therefore, it should be alerted for middle aged people or above with symptoms as follow, which could be colon cancer: change of habit of bowel movement over a short period of time, such as diarrhea, constipation, or unsmooth bowel movement, persistent abdominal discomfort, vague pain or bloating; loose stool, the presence of blood or mucus in stool; repeated positive in occult blood test; unidentified anemia, week or weight loss, mass palpable in abdomen.
Any of these symptoms requires systemic health checks to exclude the possiblity of colon cancer apart from consultation with the doctor about medical history and physical examination.
1. CEA (Serum Carcinoembryonic antigen) measurement: nonspecific to the diagnosis of colon cancer. An increased level is associated with bigger size of tumor, which will go back to normal level followed by total resection of colon cancer and rebounce to an increased level weeks before recurrence. Therefore, it can help evaluate prognosis and monitoring therapeutic effects and recurrence. CEA is the most commonly used means for diagnosis of colon cancer.
2. Ultrasonography, CT scan or MRI: any of these three means can not determine the diagnosis of colon cancer, however, it has advantages of identifying location of tumor, size and relation to surrounding tissues, lymph node and liver metastases. It is mainly used to determine the infitration into intestinal canal and presence of local lymph node or distal organ metastses.
3. Stool test: M2-PK level in the stool from colon cancer patient is 14 times that that from normal people. Therefore, M2-PK test can be a new innovative method for screening colon cancer.
4. X ray: consists of entire digestive tract Barium test and Barium enema. X ray can get a overal picture of colon appearance, the presence of multiple polypt and multi-cancer lesions and serves as evidence for surgery.At early stage, there might be rigidity of intestinal wall, mucous membrane destruction, then, permenant filling defect, stenosis of intestinal canal. Double contrast gas barium can achieve better results.