People living with HIV are at an increased risk of developing anal cancer, particularly if they have compromised immune systems. (Photo: Bild von Tung Lam/Pixabay)News & Features
17th November 2025 | Elna Schütz
South Africa has the world’s largest population of people living with HIV, which both heightens the risk of anal cancers and their severity. However, neither the collection of data nor the efforts for prevention and screening are in line with the likely impact. Experts say significant change is needed.
“Almost everyone has an anus,” Dr Daniel Surridge, a colorectal surgeon at Joburg Colorectal, says with a smile. He is one of a group of specialists trying to draw attention to arguably one of the most neglected areas in cancer.
“We’re quite a weird niche group who talk about bums all day, but most people are really in denial that they have an anus,” jokes Dr Tim Forgan, another colorectal surgeon, working in the private and public sector in Cape Town.
“It’s such an essential part of your daily life and you need your anus,” adds Dr Mark Faesen, specialist gynaecologist with the Clinical HIV Research Unit (CHRU), who runs an anal cancer screening clinic at Helen Joseph Hospital in Johannesburg, as far as we know, the only one in the country.
The stigma surrounding this particular body part, unfortunately, does no one any favours when it comes to cancer awareness and treatment.
A tricky hidden cancer
Anal cancers occur in the last few centimetres towards the external opening of the rectum. They can be associated with rectal, colon, or genital issues.
Professor Michael Herbst, health specialist consultant for the Cancer Association of South Africa, explains that the vast majority of these cancers are anal squamous cell carcinomas, meaning they develop in the skin cells of the anal canal.
Most anal cancers are caused by Human Papillomavirus (HPV), a virus that also causes most cases of cervical cancer.
“Patients and doctors often misdiagnose those early symptoms as haemorrhoids,” Herbst says, explaining that the disease is asymptomatic at first. Later, it may present with itching, discharge, bleeding or a palpable lump.
Ideally, a diagnosis is made of a pre-malignant lesion, which is a fairly flat, slightly dark growth. This can be found through a rectal exam or smear. A biopsy under anaesthesia may be needed to confirm the diagnosis.
Premalignant lesions can be treated topically if caught early. Otherwise, the skin may have to be surgically removed, which is often a difficult and risky surgery in this part of the body.
Once a lesion has progressed to cancer, treatment involves high doses of chemotherapy and radiation, which Surridge says is intense and only treats about half of patients effectively. “The rest go to a surgery where you have to remove the anus along with the rectum and put in a permanent colostomy bag,” he says.
In comparison to the rectal and colon cancers that Surridge sees in his work, he describes anal cancers as less predictable and more aggressive, with painful consequences. “It’s going to hurt like hell,” he says. “It stinks like you’re rotting from the inside, so no one wants to come near you.”
Anal cancers are also particularly resistant to chemotherapy, Surridge says, and run the risk of spreading through the lymph system, leading to a dismal outcome, possibly leading to death.
People living with HIV are at an increased risk of developing anal cancer, especially if they have compromised immune systems.
Faesen says that internationally, in the general population, the incidence of anal cancer is around 2 per 100 000 people per year. “If you’re HIV positive long enough, so over the age of 45, the risk is 20 to 40 per 100 000 per year,” he says. For men who have sex with men, the incidence can be as high as 60 or 130 per 100 000.
Those with HPV and patients with immune systems not working as well as they should, such as those who have received an organ transplant, are at risk. Furthermore, groups who engage in high-risk sexual activities, like men who have anal sex with multiple male partners, should be aware of the risk. However, sexual orientation and anal sex do not directly lead to an increase in anal cancer risk.
Rare but not that rare
Anal cancer may be considered a rare cancer, but the few local experts on it see it as a concerning cancer because of South Africa’s high number of people who are at increased risk.
“Anal cancer is strangely common in South Africa. It’s not extremely common, but it is reasonably common,” says Forgan.
The National Cancer Registry’s latest numbers, from 2023, has the cancer reported in around 300 women and 220 men, making up less than 0,7% of reported cancers. A recent analysis of the registry’s numbers found that the cancer’s incidence has significantly increased between 1994 and 2021. The paper found that younger black women and older white women were most likely to get the cancer. A study at the University of the Witwatersrand in 2023 found that three-quarters of their anal cancer cohort were female and 80% were HIV positive.
“We don’t actually know the true incidence in South Africa,” says Dr James Pattinson, Head of Colorectal Surgery at Chris Hani Baragwanath Academic Hospital, explaining that the disease is likely under-reported. Anecdotally, he says the cancer seems common in Gauteng. He says his unit alone sees around 100 new cases of anal cancer a year, making up around 30% of new reported colorectal cancers.
Surridge says it is getting more common, and “it is certainly raging through Gauteng”.
The challenges
The doctors agree that the reported numbers are likely lower than the real prevalence and that many cases could be avoided or caught early with intervention. A key factor is the lack of education and patient hesitancy to get tested. “The natural stigma and embarrassment associated with anal conditions cause patients to wait until the condition is severe before seeking medical help,” Pattinson says.
“The lack of awareness doesn’t stop at the door of the Department of Health,” Faesen says. He laments that few healthcare workers are well-informed about this cancer. This leads to misdiagnoses and problems being missed. This is aggravated by financial and resource constraints. But, he says, this is not a “blame game”, since the greater awareness of anal cancer is fairly new.
For instance, the International Anal Neoplasia Society’s consensus guidelines for anal cancer screening were only released in early 2024. Faesen explains that while cervical cancer screening was popularised internationally around the 1960s, it was only a study published in the New England Journal of Medicine in 2022 that found that treating lesions substantially lowers the risk of anal cancer, that heightened the interest in screening.
In that study, of over 4 000 people, progression to anal cancer was more than 50% lower in people who received treatment for precancerous lesions than in people who did not. The study provided a compelling rationale for increased screening, since it is only through finding precancerous lesions in the first place that they can be treated and progression to cancer be prevented.
Reaching the level of common-place awareness for anal screening that there is around cervical pap smears is still a while away. “It took 50 to 60 years to get there, but we’ve just started,” Faesen says. “We are at the absolute beginning of anal cancer awareness.” He does however note that the incidence of anal cancer in some South African populations is already much higher than that of cervical cancer when routine screening for that was started.
What to do
The lack of screening for anal cancer is one clear issue that needs to be addressed. “Hopefully, we can demonstrate with more and more screening that there is a need for it,” Faesen says. He hopes that this will catch the problem before it progresses to a serious disease in more patients.
However, Pattinson notes that screening in other countries has been historically focused on high-risk populations such as men who have sex with men. “This is obviously not feasible in South Africa, as high-risk individuals are the millions of people living with HIV.”
Screening could potentially be focused on certain sites, like HIV-specific clinics or doctors who particularly work with HPV and cervical screening. Expanding screenings for high-risk groups to include anal would not be incredibly expensive but would add an extra burden on staff, Forgan says. “And it’s a very easy thing to screen for. You just have a look.”
HPV vaccination switching to single-dose and private schools to get govt supply
The @HealthZA is switching from a two-dose to a single-dose vaccine regimen and girls in private schools are set to receive state subsidised jabs. @catherinetom reports.https://t.co/7HRXt37vpp
— Spotlight (@SpotlightNSP) June 20, 2024
There is also a preventative solution, the HPV vaccine. A two-strain form of this vaccine is already offered to girls aged 9 to 12 years old by the Department of Health. This does not cover other strains and is mostly focused on cervical cancer.
Surridge says that focusing on vaccinating only girls means boys aren’t protected, and creates a possible lag in protection against anal cancer. He says the vaccine, ideally one with more strains, if possible, should be given to as many people as possible.
“If you’re in a higher risk group, like those (who are) immuno-suppressed, with HIV, or solid organ transplant recipients, you should be vaccinated,” Forgan says. “Then you wouldn’t need a screening programme, per se, because you had prevented it from happening.”
Beyond this, increasing education around the disease and eventually instituting local guidelines would be crucial.
The National Department of Health did not respond to questions from Spotlight about their plans relating to anal cancer.
