Anal cancer doesn’t get a lot of attention. This may be because it’s relatively rare – anal cancer affects an estimated one to two Australians^[1] in every 100,000. As a comparison, melanomas affect around 70 in every 100,000 people.

But it’s also likely due to embarrassment. Anal cancer is an abnormal growth in the cells lining the anus, the last few centimetres of the bowel. Many people feel awkward talking about this part of their body.

So, when symptoms appear – such as bleeding or itchiness – they may delay speaking to a doctor. But it’s crucial to know what to look for, because if anal cancer is caught early the chances of treating it are much higher.

Do we know what causes it?

Up to nine in ten^[3] anal cancers are caused by human papillomavirus (HPV), a sexually transmitted infection.

HPV is common – more than 80% of people^[4] who have ever been sexually active will be infected at some point with a strain (there are more than 150^[5]).

Most HPV strains won’t cause any problems. But some, particularly HPV16^[6], are higher risk. Persistent infection can cause changes in the anal lining and this can progress to anal cancer. This can happen even if you don’t have anal sex.

Vaccination against HPV is a highly effective method^[7] to reduce the risk of cancers related to HPV infection such as anal and cervical cancer.

Since the national HPV vaccination program^[8] began in Australia in 2007, there has been a substantial drop^[9] in diseases linked to HPV (such as genital warts). While it’s too early to say, it is hoped that over time cancer rates will also fall due to vaccination.

Other^[10] factors that increase your risk for anal cancer include^[11]:

• being older
• a history of smoking
• a weakened immune system (for example from medication or HIV)
• sexual activity (having anal sex or multiple sexual partners)
• a history of cervical, vulval or vaginal cancer.

What are the symptoms?

Sometimes anal cancer doesn’t cause any symptoms. A doctor may instead detect the cancer visually during a colonoscopy or another examination.

Other times, symptoms may include^[13] bleeding from the bottom (you might see blood on the toilet paper), a new anal lump, or feeling non-specific discomfort or itchiness in your anus.

You may also have an unusual sensation that you can’t pass a stool as “fully” or easily as before.

If you have any of these symptoms – particularly if they are new or getting worse – it is important to speak with your doctor.

The symptoms of anal cancer can be very similar to common conditions such as haemorrhoids^[14], so it’s best to get them checked by a doctor to get the diagnosis right.

It’s understandable you might be embarrassed. But for doctors, this is all part of routine practice.

Catching it early improves your chances

Survival rates are much better for anal cancer caught in the early stages.

Around 90% of people^[15] diagnosed with stage one anal cancer will live five years or more. That drops to 60% if the diagnosis is made when the cancer has developed to stage three.

The test may be as simple as a quick anal examination. Or it may require other investigations such as anoscopy (looking inside the bottom with a slim tube) or specialised ultrasounds or scans.

Most tests involve only a small amount of discomfort or none at all. They can rule out anything serious, giving you peace of mind.

If a cancer is detected, treatment usually involves radiotherapy, chemotherapy or surgery, or a combination.

The bottom line

If you need another reason to get symptoms checked out, here’s one: they could also indicate bowel cancer.

Bowel cancer^[16] (also known as colon or colorectal cancer) is the fourth most common cancer diagnosed in Australia, and the second most common cause of cancer death, with similar symptoms such as bleeding from the bottom.

So, it’s crucial to not to let awkwardness get in the way. Speak to your doctor if any symptoms concern you. Starting the conversation early could save your life.

References

1. ^{^} one to two Australians (www.aihw.gov.au)
2. ^{^} Designua/Shutterstock (www.shutterstock.com)
3. ^{^} nine in ten (www.cancercouncil.com.au)
4. ^{^} more than 80% of people (www.thewomens.org.au)
5. ^{^} more than 150 (www.hpv.org.nz)
6. ^{^} particularly HPV16 (pubmed.ncbi.nlm.nih.gov)
7. ^{^} a highly effective method (www.hpvvaccine.org.au)
8. ^{^} national HPV vaccination program (www.health.gov.au)
9. ^{^} substantial drop (pubmed.ncbi.nlm.nih.gov)
10. ^{^} Other (www.cancer.gov)
11. ^{^} include (www.cancer.org.au)
12. ^{^} wisely/Shutterstock (www.shutterstock.com)
13. ^{^} symptoms may include (www.cancer.org.au)
14. ^{^} haemorrhoids (www.analcancerfoundation.org)
15. ^{^} 90% of people (www.cancerresearchuk.org)
16. ^{^} Bowel cancer (www.canceraustralia.gov.au)