Colon Cancer – investigations
– Rigid rectoscopy (rectal cancer);
– Flexible Recto-sigmoidoscopy (recto-sigmoid neoplasm);
– Colonography – CT;
– Hemocult test.
Rigid rectoscope helps exploring the first 20-25 centimeters of the rectum and sigmoid colon. This method allows the diagnosis of rectum cancer. If this investigation is completed with a rectal examination and anoscopy the evaluation of terminal portion of the digestive tract will be done correctly. The rectoscope is rigid, made of metal and is not expensive.
Flexible sigmoidoscopy helps to explore descending colon and sigmoid (even reach up to splenic angle). On this portion of the colon are found almost 80% of colon cancers. Preparation before exploring is easy, the patient will have to make two enemas. For the patient will not be too much discomfort.
Using colonoscopy the entire colon can be explored and can take biopsies (pieces of tissue for pathology examination). Also, using a colonoscope it can be made small interventions, such as removing polyps (polypectomy), hemostasis. This method is expensive and discomfort felt by the patient is high enough. Patient preparation consists of drinking a quantity of 3-4 liters of substance with purgative effect (Fortrans).
Irigography is an older method, widely used, but today is gradually replaced by colonoscopy. The method consists in the administration of a substance through the rectum and performing x-rays. The downside is that you can not take biopsies and small interventions can not be made.
Virtual colonoscopy consists of colon reconstruction after performing a CT of the abdomen. This method allows highlighting a potential polyp and cancer. The disadvantage is that biopsies can not be taken and it can not be performed therapeutic interventions (polypectomy).
Transrectal EUS is used to see the extension of rectal cancer in tissue layers. It can evaluate the extent of cancer, in particular in the rectal area.
Hemocult test investigates occult bleedings (chronic bleeding, in small amounts, but which can lead to anemia). If the test is positive (is made in asymptomatic persons as a screening test) the suspects will proceed to conduct an investigation as mentioned above (colonoscopy). Hemocult test 2 is more specific and is not required to follow a special treatment before performing it.
A modern test, but expensive is the determination of modified DNA from stools.