A biopsy is the removal of cells or tissue to be examined under a microscope. This exam can show if the tissue is cancer. For colorectal cancer, a biopsy is the only way to be sure of the diagnosis. The most common type of biopsy is an endoscopic biopsy. This is usually done during a colonoscopy. Other types of biopsies include a needle biopsy and a surgical biopsy. But these are not often used to diagnose colorectal cancer. Needle biopsies are sometimes used in other parts of the body to see if the cancer has spread. Surgical biopsies are used to take samples of large tumors. They are also used for tumors in hard-to-reach places.
Once your healthcare provider removes the tissue, he or she sends it to a lab. There a doctor called a pathologist looks at the tissue under a microscope to check for cancer cells. It usually takes several days for the results of your biopsy to come back. A biopsy is the only sure way to tell if you have cancer. And it is the only way to tell what kind of cancer it is.
Below are the 3 types of biopsies a healthcare provider may do:
Most biopsies can be done with 1 of the above methods. But if the polyp or mass the healthcare provider wants to examine is large or in a hard-to-reach spot, you may need to have surgery. You'll be given general anesthesia so that you fall asleep and don't feel anything. You may also have to stay overnight in the hospital. It may take several days before you can go back to your normal routine.
Most polyps are benign. That means they are not cancer. The biopsy will show exam will reveal if the polyps are abnormal cell growth (dysplasia) or cancer (carcinoma). If you have a dysplastic polyp, you are at higher risk for growing more polyps and cancer.