Usually you begin by seeing your GP who will examine you and refer you to a specialist in bowel conditions (gastroenterologist).
At the hospital the doctor will ask you about your general health and any previous medical problems. They will also examine you and take blood samples to check your general health and that your liver is working properly. Before the doctor can make a firm diagnosis of anal cancer a number of tests will have to be done.
Rectal examination This is also sometimes known as a PR examination and is where the doctor examines your back passage with a gloved finger.
Biopsy A small sample of cells is taken from the tumour so that it can be examined under a microscope. Usually this involves using either a special biopsy device (known as a punch biopsy) or the doctor can cut a small piece away from the tumour (known as an incisional biopsy). This can be done under local or general anaesthetic.
If the tests show that you have anal cancer, you may need further tests to see if the cancer has begun to spread.
X-rays These may be taken to show if there has been any spread of the cancer.
Ultrasound scan This is a simple scan that uses sound waves to form a picture of the inside of the abdomen. These scans are done in the hospital's scanning department. Once you are lying comfortably on your back, a gel is spread onto your abdomen. A small device is then moved over the area. The sound waves are converted into a picture using a computer. The test is completely painless and takes 15–20 minutes.
You may also have an ultrasound scan known as an endoanal ultrasound. For this scan a small probe is passed into the back passage (rectum), which can show the size and extent of the tumour.
CT (computerised tomography) scan This is a more sophisticated type of x‑ray which builds up a three-dimensional picture of the inside of the body. The scan is painless, but takes longer than a simple x-ray (10–30 minutes). It may be used to identify the exact site of the tumour or to check for any spread of the cancer. Most people who have a CT scan are given a drink or injection to allow particular areas to be seen more clearly. Before having the injection or drink, it is important to tell the person doing this test if you are allergic to iodine or have asthma.
MRI (magnetic resonance imaging) scan This test is similar to a CT scan, but uses magnetic fields instead of x-rays. During the scan you will be asked to lie very still on a couch inside a metal cylinder. You will usually be given an injection to allow the pictures to be seen more clearly.
The test can take about 30 minutes and is completely painless, although the machine is quite noisy. You will be given earplugs or headphones. If you don’t like enclosed spaces you may find the machine claustrophobic. A two-way intercom enables you to talk with the people controlling the scanner.