Anal cancer starts in the anal canal — the short passage at the end of your bowel, just inside your back passage. It is quite different from bowel (colorectal) cancer, which starts higher up in the colon or rectum, and is treated in a different way.
The most common kind of anal cancer is called squamous cell carcinoma, which comes from the skin-like lining of the anal canal. The reassuring news is that anal cancer responds very well to a combination of chemotherapy and radiotherapy — and most people are cured without ever needing major surgery.
If you have just been told you might have anal cancer, please take a breath. You are doing exactly the right thing by finding out more, and there is an experienced team around you.
Most anal cancers are linked to a virus called human papillomavirus (HPV) — the same virus responsible for some cervical cancers in women. HPV is very common, and most people who carry it never develop a cancer from it.
Other things that increase the risk include having had anal warts in the past, having a weakened immune system (for example with HIV, after a transplant, or with long-term immunosuppression for autoimmune disease), smoking, and a personal or family history of cervical or vulval pre-cancer. The HPV vaccine — now given to teenagers as part of the routine national immunisation program — substantially reduces the risk of HPV-related cancers including anal cancer.
Having one or more of these risk factors does not mean you will get anal cancer — most people with these factors never do. But knowing your risk helps your doctor decide what to look for.
Anal cancer can cause: bleeding from the back passage, a sore or ulcer around the anus that does not heal, a small lump that you can feel, discomfort or pain in the area, itching that will not settle, or a change in your bowel habits.
Here is the difficulty: every one of these symptoms is far more often caused by something completely benign — most commonly haemorrhoids, a fissure, or simple irritation. That is why most people with these symptoms do not have cancer. But because the symptoms overlap, it is always worth having anything that has not settled within a few weeks looked at properly. Getting it checked is the kindest thing you can do — usually it brings reassurance, and on the rare occasions when something serious is found, finding it early matters.
Diagnosing anal cancer starts with a careful examination by your specialist, and a small tissue sample (called a biopsy) is taken so the cells can be examined under the microscope to confirm the diagnosis. The biopsy is usually done under a short anaesthetic — called an examination under anaesthetic, or EUA — so the area is properly assessed without any discomfort.
Once a cancer is confirmed, the next step is called staging. This means finding out how big the cancer is and whether it has spread anywhere. Staging usually involves an MRI of the pelvis, a CT of your chest and abdomen, and sometimes a PET-CT scan. Staging helps your team plan the right treatment for you.
The main treatment for most anal cancers is not surgery — it is a combination of chemotherapy and radiotherapy, given together over about 5–6 weeks. This is sometimes called the Nigro regimen (after the doctor who first described it), and it is one of the most effective treatments in cancer care. The vast majority of people are completely cured by it.
Surgery is only needed if the cancer does not respond to chemoradiotherapy, or if it comes back later — and in that case the operation is usually one called an abdominoperineal resection (APR), which involves a permanent colostomy (a bag for bowel motions). Very small, very early anal cancers can occasionally be treated with a simple local excision — just removing the small area without further treatment.
Your treatment will be planned and coordinated by a multidisciplinary team (MDT) — a group of specialists including surgeons, radiation oncologists, medical oncologists, radiologists and pathologists working together. You will never just be one person's patient.
Mr Nguyen is often the first specialist you will see — to examine the area, take a biopsy at an EUA, and start coordinating the rest of your care. Once anal cancer is confirmed, he works alongside your radiation and medical oncologists in the MDT, with continued involvement in your surveillance afterwards. If salvage surgery ever becomes necessary, he will discuss the operation, what it involves, and what life will be like afterwards in honest detail — so you know exactly what to expect.
Clear, honest, unhurried communication matters as much as the medicine. You and your family will always know what is happening and why.
Please do not wait if you have noticed any of these for more than a few weeks: bleeding from your back passage, a persistent lump or ulcer near the anus, ongoing anal pain or itching, or a change in your bowel habits. Most of the time these are caused by something benign, but they always deserve a proper check.
Your GP will arrange a referral. At the consultation, a careful history is taken, the area is gently examined, and the next steps are discussed. If a biopsy is needed, it is usually done as a short day procedure under anaesthetic. If anal cancer is confirmed, the treatment pathway is explained step by step and the MDT is brought in — you will not be navigating this alone. Most anal cancers are treated with the aim of curing them completely.
No — they are different cancers. Bowel cancer starts in the colon or rectum and comes from a different cell type. Anal cancer starts in the anal canal and is usually a squamous cell carcinoma (cancer of the skin-like lining). The treatments are quite different — bowel cancer is mainly treated with surgery, whereas anal cancer is usually treated with chemotherapy and radiotherapy.
Most people with anal cancer never need a colostomy. The first-line treatment (chemoradiotherapy) usually cures the cancer while keeping everything working normally. A colostomy is only needed if the cancer does not respond to chemoradiotherapy, comes back later, or has affected the sphincter muscle so much it cannot be saved. If a colostomy ever becomes a consideration, that conversation happens clearly and in detail — including what life with one looks like.
Most anal cancers are linked to HPV (human papillomavirus). HPV is a very common virus and most people who have it never develop a cancer. HPV vaccination — now given to teenagers as part of the routine immunisation program — substantially reduces the risk of HPV-related cancers later in life.
Very effective. The combination treatment for anal cancer is one of the most effective in modern cancer care — the majority of people are completely cured and avoid the need for major surgery. The treatment lasts about 5–6 weeks and has its own side effects (which your radiation oncologist will explain in detail), but most people get back to normal life within a few months of finishing.
Have questions about anal cancer?
Mr Nguyen sees patients at his consulting rooms in Heidelberg and operates at Warringal Private and Epworth Eastern. A GP or specialist referral is required.