Colorectal Cancer – Diagnostic Procedures

Diagnosis & Tests

Screening could help in diagnosing polyp growths prior to them turning malignant and for detecting colon cancer in its preliminary stages when the recovery rates are much higher. The widely used screening and analytic procedures for colorectal cancer are:

• Fecal Occult Test or Blood Stool Test – This procedure is used for checking any traces of blood in the stool or feces. This test could be conducted at the office of the general practitioner, the primary care doctor or in most cases a self-explanatory kit is provided for taking the sample at one’s home. The sample taken is then to be returned to the doctor’s office in order to be forwarded for laboratory analysis. A blood stool test does not have total accuracy as not all cancers can be identified since bleeding does not occur in all of them. Even cancers that bleed regularly tend to occur on a sporadic basis. Hence, it is likely that a negative test outcome could arise when actually the patient would be having cancer. Even when blood is noticed, it could be occurring due to the presence of other ailments or conditions like haemorrhoids. There might be certain food types that might suggest blood in the colon, when in actuality; there is no presence of blood.
• Stool DNA Test – This test examines numerous DNA markers that colon cancers or pre-malignant polyp cells tend to discard into the feces. A kit along with ‘to-do’ instructions is provided to the patient for collecting the stool sample at their home which is then to be submitted in the doctor’s office for detailed laboratory analysis. This test has greater accuracy in spotting colon cancers as compared to polyp detection. Though, it fails to recognise all DNA mutations that might signify the presence of the tumor.
• Flexible Sigmoidoscopy – With the assistance of a pliable, fine and illuminated tube known as a sigmoidoscope, an examination of the rectum and sigmoid (sigmoid colon is the last part of the colon that then leads to the rectum)is done. The tests usually last for some minutes and does not cause pain, though some discomforting sensation might be sensed. The likelihood of puncture to the colon wall might occur during the procedure. In case polyps are detected, then a colonoscopy would be performed for examining the colon in whole and for removal of any polyps that might be present that would then be microscopically analysed. A sigmoidoscopy would merely spot polyps or cancerous growths that might be existent in the last part of the colon and the rectum. It fails to identify polyps that might be present in the other areas of the digestive tract.
• Barium Enema X-rays – Barium is a contrasting dye inserted in an enema form into the bowel so that it would appear on an X-ray. Air is additionally added in a double-contrast barium enema. The barium inundates and forms a coating in the bowel lining that helps to create lucid images of the rectum, colon and infrequently of a tiny section of the small intestine. A pliable sigmoidoscopy is mostly used in this procedure for detecting any presence of small polyps that the barium enema X-ray might have accidentally skipped. In case any irregularity is discovered in the barium enema X-ray then the doctor would suggest going in for a colonoscopy.
• Colonoscopy – During this procedure the doctor employs a longish, bendable and slim tube known as a colonoscope that is longer in shape as compared to the sigmoidoscope. The colonoscope helps in viewing the entire colon and rectum and any polyps detected during the examination are instantly removed – at times the tissue samples might also be removed (biopsy procedure), however it is not a painful procedure. Though colonoscopy procedure is pain-free, few of the patients might be offered a mild version of a sedative in order to instil a sense of calmness. Some form of laxatives would be given to the patient prior to the procedure for clearing out the bowels from the colon (enemas are atypically employed). Bleeding and puncture to the colon wall could be likely, though they are uncommon complications during this procedure.
• CT colonography or virtual colonoscopy – A computerized tomography or CT scan machine is employed for taking images of the colon. The colon needs to be totally cleared out prior to this examination for the test to be totally effectual. In case any anomalous growth is identified, a conventional colonoscopy would become necessary in such a situation. A study has shown that CT colonography was lesser-invasive, was tolerated better by the patients and had an optimal diagnostic precision as compared to colonoscopy.
• Ultrasound Scan – Sound waves are employed to assist in detecting if the cancer has metastasized to the other body parts.
• Magnetic Resonance Imaging or MRI – This offers 3-D imagery of the bowel that assists in diagnosis.

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