However, some people with anal cancer don't have any symptoms.
See your GP if you develop any of the above symptoms. While they're unlikely to be caused by anal cancer, it's best to get them checked out.
Diagnosing anal cancer
Your GP will usually ask about your symptoms and carry out some examinations.
They may feel your tummy and carry out a rectal examination. This involves your doctor inserting a gloved finger into your bottom so they can feel any abnormalities. Your GP will refer you to hospital if they think further tests are necessary.
The National Institute for Health and Care Excellence (NICE) recommends in its 2015 guidelines that GPs should consider referring someone with an unexplained anal lump or anal ulcer. The person should receive an appointment within two weeks.
If you're referred to hospital, a number of different tests may be carried out to check for anal cancer and rule out other conditions.
Some of the tests you may have include a:
sigmoidoscopy – where a thin, flexible tube with a small camera and light is inserted into your bottom to check for any abnormalities
proctoscopy – where the inside of your rectum is examined using a hollow tube-like instrument (proctoscope) with a light on the end
biopsy – where a small tissue sample is removed from your anus during a sigmoidoscopy or proctoscopy so it can be examined in a laboratory under a microscope
If these tests suggest you have anal cancer, you may have some scans to check whether the cancer has spread. Once these are complete, your doctors will be able to "stage" the cancer. This means giving it a score to describe how large it is and how far it has spread.
surgery – to remove a tumour or a larger section of bowel
In cases where the cancer has spread and can't be cured, chemotherapy alone may be considered to help relieve symptoms. This is known as palliative care.
The main treatments are described in more detail below.
Chemoradiation is a treatment that combines chemotherapy (cancer-killing medication) and radiotherapy (where radiation is used to kill cancer cells). It's currently the most effective treatment for anal cancer. You don't usually need to stay in hospital when you're having chemoradiation.
Chemotherapy for anal cancer is usually given in two cycles, each lasting four to five days, with a four-week gap between the cycles. In many cases, part of the chemotherapy is delivered through a small tube called a peripherally inserted central catheter (PICC) in your arm, which can stay in place until your treatment has finished.
The tube means you don't need to stay in hospital during each of the cycles of chemotherapy. However, you'll be attached to a small plastic pump, which you take home with you.
A few hospitals now offer tablet chemotherapy for anal cancer, which avoids the need for the pump and PICC.
Radiotherapy is usually given in short sessions, once a day from Monday to Friday, with a break at weekends. This is usually carried out for five to six weeks. To prepare for radiotherapy, additional scans will be required.
These side effects are usually temporary, but there's also a risk of longer-term problems, such as infertility. If you're concerned about the potential side effects of treatment, you should discuss this with your care team before treatment begins.
Other possible long-term side effects can include:
Tell your doctor if you develop any of these symptoms so they can be investigated and treated.
Surgery is a less common treatment option for anal cancer. It's usually only considered if the tumour is small and can be easily removed, or if chemoradiation hasn't worked.
If the tumour is very small and clearly defined, it may be cut out during a procedure called a local excision. This is a relatively simple procedure, carried out under general anaesthetic, that usually only requires a stay in hospital of a few days.
If chemoradiation has been unsuccessful or the cancer has returned after treatment, a more complex operation called an abdominoperineal resection may be recommended. As with a local excision, this operation is carried out under general anaesthetic.
An abdominoperineal resection involves removing your anus, rectum, part of the colon, some surrounding muscle tissue, and sometimes some of the surrounding lymph nodes (small glands that form part of the immune system) to reduce the risk of the cancer returning. You'll usually need to stay in hospital for up to 10 days after this type of surgery.
During the operation, a permanent colostomy will also be formed to allow you to pass stools. This is where a section of the large intestine is diverted through an opening made in the abdomen called a stoma. The stoma is attached to a special pouch that will collect your stools after the operation.
Before and after the operation, you'll see a specialist nurse who can offer support and advice to help you adapt to life with a colostomy. Adjusting to life with a colostomy can be challenging, but most people become accustomed to it over time.
having a weakened immune system – for example, if you have HIV
Your risk of developing anal cancer increases as you get older, with half of all cases diagnosed in people aged 65 or over. The condition is also slightly more common in women than men.
The outlook for anal cancer depends on how advanced the condition is when it's diagnosed. The earlier it's diagnosed, the better the outlook.
Compared with many other types of cancer, the outlook for anal cancer is generally better because treatment is often very effective. Around 66 out of 100 people (66%) with anal cancer will live at least five years after diagnosis, and many will live much longer than this. There are about 300 deaths from anal cancer each year in the UK.