Anal Cancer in Women: Let’s Talk About It
Whilst not particularly glamorous, anal cancer doesn't get the airtime it deserves. It's not part of the standard women's health conversation, and most people, understandably, have never given it a moment's thought - which is part of the problem.
To the surprise of many, including many clinicians, women make up the single largest group of people diagnosed with anal cancer. In the United States, where the data is most comprehensive, women account for around two-thirds of all new anal cancer diagnoses each year, a pattern seen consistently across high-income countries.
Reassuringly, anal cancer remains uncommon in absolute terms and is considered a rare cancer. It is, however, increasing in incidence and is under-recognised in women's health settings. For certain women, such as those with a history of gynaecological cancers or precancers, the risk is real enough to warrant a conversation. So, let's have it!
So, what is anal cancer, and how does it start?
Anal cancer arises from the skin around or lining the anal canal. Like cervical cancer, the overwhelming majority of cases, around 90% in fact, are caused by human papillomavirus (HPV), particularly the high-risk strain HPV 16.
If you've ever had a cervical smear or been told about HPV as part of your gynaecological care, you already understand the basics. HPV is extremely common - most people encounter it, usually during sex, at some point in their lives. They don’t develop any symptoms and clear it without ever knowing they had it. But in some people, high-risk HPV can persist and, over years or decades, cause cellular changes that if left undetected, can progress to cancer. In the cervix, we screen for this routinely with Pap smears and HPV testing. In the anus, the same process takes place, but screening and awareness are considerably lagging.
For more information on HPV and its association with cancer, have a read of our blog on HPV and anal cancer.
What puts women at higher risk?
For most women, the risk of anal cancer is low. But for some, it's significantly elevated, and it’s worth knowing if you’re in that group.
The most significant risk factors for women are:
A history of vulvar precancer (HSIL) or vulvar cancer — this is classified as a high-risk category by the International Anal Neoplasia Society (IANS), the leading global body on anal cancer screening (1).
A history of cervical or vaginal precancer (HSIL) or cancer — a 2025 study published in JAMA confirmed that women with a history of cervical cancer have a significantly elevated rate of anal cancer diagnosis over time, with risk increasing the further out from their original diagnosis (2).
Persistent gynaecological high-risk HPV, particularly HPV 16
Smoking, which impairs the immune system's ability to clear HPV
Immunosuppression from any cause, including autoimmune conditions or immunosuppressive medications
The underlying reason is HPV. If HPV has already caused disease in one part of the genital tract, it’s easy for it to affect neighbouring areas too, including the anus. Women with a history of gynaecological precancer are, in a sense, an overlooked group: screening is easiest and tends to focus on the highest risk groups where the risk is most dramatic, and that has historically meant other populations.
So why do women make up the majority of anal cancer diagnoses overall, given that the overall number of women with these specific risk factors is low? It comes down to anatomy and HPV biology. The cervix, vagina and vulva sit close to each other and share the same HPV exposure risk, meaning HPV can spread between these sites without anal intercourse ever occurring. Studies suggest that around half of women with anal cancer have never had anal sex. Interestingly, even wiping technique may play a role - an Australian study found that front-to-back wiping after toileting was associated with a significantly increased risk of anal HPV and precancerous changes in women with a history of gynaecological precancer, presumably by mechanically transferring HPV from the vulva to the anal region (3).
In contrast, heterosexual men without specific risk factors have very limited pathways for HPV to reach the anal canal, so their rates are lower. Most men who develop anal cancer are overwhelmingly men who have sex with men, and men living with HIV.
In short, women without specific risk factors are not at dramatically elevated risk, but because female anatomy creates more opportunities for HPV to spread to the anal region, women collectively account for more cases across the general population than men do.
What about symptoms?
Most women with anal pre-cancer have no symptoms at all. That's why screening is so valuable for those in high-risk groups.
When symptoms do occur, these often represent anal cancer itself (and not the pre-cancer). Symptoms include:
Bleeding from the anus
Persistent anal itch or irritation
Pain or discomfort in the anal area
A lump or swelling near the anus
Changes in bowel habits and narrow stools
If you're wondering whether rectal bleeding is something to worry about, our blog on the causes of rectal bleeding explains the range of possibilities and when to seek further assessment.
Not all anal symptoms are from haemorrhoids! The key message is that patients frequently assume or are told that their anal symptoms are attributed to something common and harmless. And whilst most symptoms are benign, it is crucial that you get it checked out if something doesn't feel right or if symptoms persist despite treatment. Outcomes are always better if sinister problems are discovered early.
Should I be screened?
Not every woman needs anal cancer screening, but for women with specific risk factors, screening is recommended and worthwhile.
Consensus guidelines published in 2024 by IANS (1), the organisation leading the way in anal pre-cancer, recommend the following groups get screened:
Women with a history of vulvar precancer (HSIL) or cancer within one year of diagnosis.
Cis women over 45 and trans women over 45 living with HIV.
Cis and trans women who have received a solid organ transplant, 10 years after transplantation.
Women aged 45 and over with a history of cervical or vaginal precancer (HSIL) or cancer are at a slightly lower risk, and so it is recommended that they discuss screening with their doctor (or get a referral to an HRA provider for this discussion).
Screening is simple and familiar. It involves an anal swab, which is essentially the same technique as a cervical Pap smear, to look for the presence of high-risk HPV or abnormal cells. If results are abnormal, the next step is a procedure called high-resolution anoscopy, or HRA.
So, what's an HRA?
If you've ever had a colposcopy after an abnormal Pap smear, HRA is basically identical, but obviously looking in a different spot! A small plastic scope (similar to a speculum) is placed in the anus, and a colposcope (an instrument that provides magnification) is used to examine the lining of the anal canal. Abnormal areas can be identified, biopsied, and if this confirms pre-cancerous changes (known as HSIL), that area can be treated before it has a chance to progress to cancer.
The landmark ANCHOR trial demonstrated that treating anal HSIL reduces the risk of progression to anal cancer by around 57% in people living with HIV (4). While this was in a specific population, it is reasonable to assume this reduced risk of cancer extends to women more broadly. We also have the benefit of knowing from decades of cervical screening that identifying and treating HPV-related precancerous change before it becomes cancer works. The anal canal is basically no different.
When HSIL is found, several treatment options are available, ranging from topical creams to ablative procedures performed under HRA guidance. A systematic review I co-authored this year concluded that, while recurrence is common, treatment is overall safe and effective, with no single treatment option clearly better than any other (5).
For more details on what HRA involves and what to expect on the day, our blog on HRA covers it thoroughly.
Let's talk about the stigma
Farrah Fawcett, actress, icon, and one of the most recognised faces of the 1970s and 80s, died of anal cancer in 2009. Before her death, she documented her diagnosis and treatment publicly, at a time when few people were willing to say the word "anal", let alone "anal cancer," out loud. She founded a foundation named after herself, dedicated to funding anal cancer research and raising awareness.
Part of the reason this disease receives so little attention in women's health spaces is that it sits at an uncomfortable intersection of stigmata - around the anus as an erogenous zone, cancer, and the misconception that anal cancer only affects certain people. Many women who are diagnosed describe feeling isolated, sometimes feeling as if they can’t share their diagnosis with others out of embarrassment or shame. That silence has consequences.
This stigma exists amongst clinicians, too. Research I have been involved in shows that surgeons rarely ask patients about anal intercourse or its role in their lives and well-being, even when it is directly relevant. Despite being a common sexual practice, reported in 28-34% of cis women in some studies (6, 7), women are the least likely of all patients to be asked. Discomfort around the topic, on both sides of the consultation, means important conversations don't happen. That needs to change.
So let's normalise it! Anal health is part of overall health. An anal swab is no different from a Pap smear. Just as we've made remarkable progress in reducing cervical cancer deaths through the cervical screening program and HPV vaccination, we have the knowledge and tools to do the same for anal cancer. But we must be willing to have the conversation, so spread the word!
What about the HPV vaccine?
Australia's school-based HPV vaccination program has been running since 2007 for girls and 2013 for boys. It protects against 9 strains of HPV, including the main ones that cause anal cancer (and other types of cancer), and those that cause genital warts. If you haven't been vaccinated, adults can still receive it, though at their own cost. It's worth noting that vaccination is primarily preventive - the current evidence does not support any benefit in people who already have anal (or vulval) pre-cancer, with a high-quality recent study finding no reduction in HSIL (pre-cancer) recurrence when the vaccine was given after treatment. (8). Vaccines, though, are safe, and can help prevent you from getting strains of HPV you may not yet have.
The real benefit of vaccination is in prevention, not treatment, and that benefit will be enjoyed most by the generations vaccinated at school age, before any exposure to HPV. Remarkably, Australia is projected to effectively eliminate cervical cancer by around 2035, largely on the back of the vaccination program. It is entirely reasonable to anticipate a similar trajectory for anal cancer over the coming decades, though the timeline will be longer than for cervical cancer. In the meantime, screening for those at elevated risk and early detection for those with symptoms remain the most important tools we have.
What to do if you have concerns
If you have a history of vulvar, vaginal, or cervical precancer or cancer, or if you're experiencing anal symptoms that concern you, it's worth having a conversation with your GP. Anal cancer is rare, and there's no need to be alarmed, but symptoms deserve proper assessment, and if you fall into one of the higher-risk groups discussed above, screening is worth discussing. Your GP can do an initial assessment and refer you to a colorectal surgeon.
If HRA is recommended, it's worth doing a little research on who performs it. Very few colorectal surgeons are trained in high-resolution anoscopy, so look for someone with specific training in HRA. You may come across the term "anal mapping," but it is an older, considerably less accurate technique that has largely been superseded. HRA specialists are still relatively few and far between in Australia, which is something the field is actively working to address.
Remember, if something just doesn't feel right, trust your instinct, and see a specialist.
For a broader overview of anal cancer, risk factors, and the screening pathway, this blog is a good starting point.
How we can help
If you have a history of cervical, vulvar or vaginal pre-cancer or cancer, or you're experiencing symptoms such as anal bleeding, pain, itching, or a persistent lump, it's worth discussing these concerns with your GP.
Dr Matt Marino provides specialist assessment, anal cancer screening and high-resolution anoscopy (HRA) in Melbourne, helping patients understand their individual risk and access appropriate care when needed.
If you're unsure whether anal cancer screening is necessary, speak with your GP or healthcare provider about your risk factors and the options available. If you would like to arrange a consultation with Dr Marino, contact us here or call on 0493 318 188 to book an appointment.
