Regular medical visits allow your doctor to do regular medical examination and evaluation of your anus, which allows him to detect early cancerous lesions before they become cancerous. An anal Pap smear can help detect precancerous changes. If you have pain or chronic rectal bleeding, your doctor may recommend an examination of your anal canal. However, to confirm the diagnosis, the following tests will be performed.
Digital rectal exam (DRE) – to examine your anal cavity, your doctor may insert a gloved finger into your anal canal to detect abnormalities such as bumps. This exam, however, is not sufficient to declare an anal cancer. It gives your doctor an idea of the health of your anus so that he can proceed with other more specific tests.
Anoscopy – an anoscopy is procedure commonly performed to visualize the anus, anal canal, and lower rectum. The method consists of inserting a lubricated instrument called anoscope into the anus to directly view the lining of the anal canal and lower rectum. An anoscopy is painless and requires no complicated preparations; however, for most patients, it is uncomfortable. Depending on the severity of the disease in your anus, your health care provider may perform a sort of special anoscopy called high resolution anoscopy (HRA); a form of anoscopy consisting of using an amplifier to get more detailed images of your anal mucosa.
Ultrasound (Sonography) – In some cases, your physician may perform an anal ultrasound to examine your anal tissue. During the procedure, he will insert a probe into your anal canal, which create images of your anus, and eventually reveals fistula or formation of scar tissue.
Biopsy – Depending on the results of the exams, mostly if lesions and tumors are found in your anal canal, your doctor may take sample of your anal tissue to be examined under a microscope. Pathologists will examine the sample to confirm or exclude a diagnosis of anal cancer. In case the cancer has spread outside the anus, it can be detected using a CT (scan) or MRI (magnetic resonance imaging).