It is advisable to see a specialist in General Surgery for early detection tests for colon and rectal cancer from the age of 50 onwards, with colonoscopy being the ideal test, although the personal characteristics of each patient should always be taken into account.
Individuals at increased risk of colorectal cancer should be screened at an earlier age than 50 years.
The main tests for detecting colon cancer are:
- Occult blood in the stool: There are several types of clinical tests in laboratories that detect the presence of blood in the stool, which can be a symptom of anything from hemorrhoids to advanced cancer. These are very sensitive tests, but if they give positive results, they would indicate the need to perform other more exclusionary tests.
- Sigmoidoscopy: This test only examines the rectum and sigmoid colon, so if a colonoscopy can be performed it is better because of its breadth. Sigmoidoscopy can be performed without sedation. Experts recommend performing this test every five years and every three years for people with risk factors. – Colonoscopy: This test examines the rectum and colon. It detects any abnormalities in the colon and rectum, which can be biopsied and even removed. Before the test, which is performed under sedation, a complete cleansing of the entire colon is necessary. A colonoscopy is recommended every 10 years in people at risk as long as normal results continue to be obtained.
- Virtual Colonoscopy: This screening method produces images of the colon and rectum with a CT-Scanner. A computer displays detailed images of the inside of the rectum and colon. Virtual colonoscopy is less invasive than regular colonoscopy and does not require sedation. A thorough cleansing of the colon is required prior to this test, and air or carbon dioxide is pumped into the colon to expand it to better see the lining of the colon. The accuracy of virtual colonoscopy is similar to that of regular colonoscopy and presents less risk of complications. The drawback is that if polyps or other abnormal tumors are found during virtual colonoscopy, they cannot be biopsied.
It is not currently known whether virtual colonoscopy helps to reduce mortality from colorectal cancer, but it is used as in those patients in whom normal colonoscopy cannot be performed for any reason.
- Double contrast Barium Enema: It is a radiological test where Barium contrast is introduced through the Anus to draw inside the Rectum and Colon. It is performed with the patient awake, biopsies cannot be taken and small lesions may go unnoticed. This method is performed if the previous ones mentioned above cannot be performed for any reason.
Other tests such as CT scan or CT scans can detect established tumors or suspicious inflammation but if it is suspected that there may be a lesion, a colonoscopy will be performed to take a sample of the lesion.
Diagnosis and treatment of colorectal cancer
The diagnosis of colorectal cancer can only be made by anatomopathological analysis of the sample removed in biopsy or excision during colonoscopy or Sigmoidoscopy. Once it has been established that colorectal cancer exists, it is necessary to perform extension tests for its best treatment.
These extension analyses include Magnetic Resonance Imaging, thoracoabdominal CT and Echoendoscopy, which provide the urologist with information on the stage of the lesion.
It is also necessary to differentiate between colon cancer and rectal cancer, since in rectal cancer, once the stage of the disease has been assessed, in those cases where there appears to be lymph node involvement, neoadjuvant therapy with chemotherapy and radiotherapy would be indicated in order to face surgery with better results in terms of survival and long-term cure.
Special mention should also be made of malignant polyps that have been diagnosed by colonoscopy and have been biopsied or removed, since sometimes the removal of the polyp by colonoscopy alone is the necessary treatment, only the Digestive specialist will indicate if a more complete surgery is required.