Anal cancer is uncommon compared with colorectal or breast cancer, but it is growing steadily more common across much of the world. Globally, more than 30,000 people were diagnosed with anal squamous cell carcinoma in 2020, with roughly two-thirds of those cases occurring in North America and Europe. Incidence rates have climbed in most high-income countries over the past three decades, and certain populations face risks many times higher than the general public. The numbers tell a story that goes well beyond a single diagnosis rate, touching on who is affected, why rates are climbing, and what prevention looks like.
How Common Is Anal Cancer Around the World
Anal cancer remains relatively rare in absolute terms, but it is not evenly distributed. The highest incidence rates have been recorded in Denmark, France, Germany, the United States, Switzerland, the United Kingdom, and Australia. In 2008–2012, Germany reported the highest overall rates, reaching roughly 1.7 per 100,000 men and 2.2 per 100,000 women per year.1PubMed Central. Global trends in anal cancer incidence and mortality At the other end of the spectrum, countries such as Japan, Turkey, China, the Philippines, and Jordan have consistently reported very low rates.2ESMO Gastrointestinal Oncology. Incidence and burden of anal cancer—time to fight the growing disparities The disease also follows a geographic mortality pattern: the highest death rates around 2020 were in parts of Central and Eastern Europe, particularly Slovakia, while the lowest were in the Philippines, Mexico, and Japan.3PubMed Central. Global trends in anal cancer incidence and mortality
In most populations that have been studied, anal cancer is more common in women than in men. That pattern holds across Australia, the Americas, and Northern and Western Europe.4International Journal of Epidemiology. International trends in anal cancer incidence rates There are exceptions: among Black Americans, male incidence surpassed female incidence in the mid-1990s, and in Spain, Israel, and Japan, rates in men have been comparable to or higher than in women.5International Journal of Epidemiology. International trends in anal cancer incidence rates
A Steadily Rising Trend
What makes these numbers concerning is their trajectory. Across high-income countries, anal cancer incidence has been climbing for decades. Rates were significantly higher in 2008–2012 than in 1988–1992 in both sexes, with the steepest increases occurring in people under 60.6PLOS ONE. Anal cancer in high-income countries: Increasing burden of disease The countries with the sharpest recent climbs include the Netherlands, Denmark, and the United Kingdom, each of which saw five-year increases of about 20% or more in age-standardized incidence between 1988 and 2012.7ESMO Gastrointestinal Oncology. Incidence and burden of anal cancer—time to fight the growing disparities In some countries the rise has been limited to women or to one sex, but the broad direction is upward nearly everywhere researchers have looked, with rates stable only in a handful of countries including India, Japan, and Singapore.8International Journal of Epidemiology. International trends in anal cancer incidence rates
Mortality trends have also been climbing in most countries for both sexes, though the increases are generally smaller than those for incidence. The fact that incidence is rising faster than mortality suggests that treatment advances and earlier detection are partially offsetting the growing number of cases, but not enough to flatten the mortality curve entirely.9PubMed Central. Global trends in anal cancer incidence and mortality
Why Rates Are Rising
Human papillomavirus, or HPV, is the central driver. High-risk HPV types, especially types 16 and 18, are considered a necessary cause of anal squamous cell carcinoma, the dominant histological subtype.10PubMed Central. Prevalence of HPV in anal cancer: exploring the role of infection and inflammation Changes in sexual behavior over the past several decades, including higher lifetime numbers of sexual partners and a rise in receptive anal intercourse, have increased the population’s cumulative exposure to anal HPV infection. That shift is widely believed to be the primary force behind the rising incidence curve.
Smoking amplifies the risk considerably. A study of premenopausal women who smoked found a roughly sixfold increase in anal cancer risk compared with lifelong nonsmokers, with risk increasing linearly with the number of pack-years smoked.11JNCI: Journal of the National Cancer Institute. Tobacco Smoking as a Risk Factor in Anal Carcinoma: an Antiestrogenic Mechanism? A population-level study in Kentucky found that about 60% of anal cancer cases occurred in people who had ever smoked, and the incidence rate among ever-smokers was roughly two and a half times that of never-smokers.12PubMed Central. Population-level incidence of human papillomavirus-positive oropharyngeal, cervical, and anal cancers, by smoking status Smoking appears to act alongside HPV rather than independently: it weakens the local immune response and may promote the persistence and progression of HPV infections that would otherwise be cleared.
Emerging research has also looked at the anal microbiome. In men who have sex with men living with HIV who also carry high-risk HPV and have precancerous lesions, researchers found an enrichment of pro-inflammatory bacteria and a reduction of anti-inflammatory species in the anal canal.13PubMed Central. Distinct anal microbiome is correlated with anal cancer precursors in MSM with HIV Whether these microbial changes help drive cancer progression or are merely a byproduct of the precancerous state is still unclear, but it represents one of the newer avenues of investigation.
Groups at Highest Risk
Certain populations face anal cancer rates that dwarf the general average of roughly 1–2 cases per 100,000 person-years. The most dramatically elevated risk is among people living with HIV. In a large U.S. study of nearly 450,000 people with HIV, anal cancer incidence was about 19 times higher than in the general population.14PubMed Central. Anal Cancer Risk Among People With HIV Infection in the United States A North American analysis covering 2001–2016 put the age-standardized incidence at about 61 per 100,000 person-years among people with HIV, and the relative risk at roughly 28 compared with HIV-negative people in the United States. For men who have sex with men (MSM) with HIV, the relative risk was even higher, at about 45 times that of the general population.15JNCI: Journal of the National Cancer Institute. Recent and projected incidence trends and risk of anal cancer among people with HIV in North America
Among gay, bisexual, and other MSM living with HIV, the incidence has been estimated at about 85 per 100,000 person-years.16The Lancet Regional Health – Western Pacific. Cost-effectiveness of screening and treating anal pre-cancerous lesions among gay, bisexual and other men who have sex with men living with HIV To put that in perspective, the incidence of anal cancer in MSM in the United States is higher than the incidence of cervical cancer among women, a disease that has its own long-established screening infrastructure.17JNCI: Journal of the National Cancer Institute. Age-Related Prevalence of Anal Cancer Precursors in Homosexual Men: The EXPLORE Study People with AIDS face a further elevation in risk compared with those who are HIV-positive but have not progressed to AIDS.18PubMed Central. Anal Cancer Risk Among People With HIV Infection in the United States
Solid organ transplant recipients, who take immunosuppressive drugs to prevent organ rejection, also have elevated risk. A meta-analysis found that their anal squamous cell carcinoma incidence was about seven times the general population rate, translating to roughly 12 per 100,000 person-years in absolute terms.19American Journal of Transplantation. Burden of anal squamous cell carcinoma, squamous intraepithelial lesions and HPV16 infection in solid organ transplant recipients: a systematic review and meta-analysis A large study of more than 15,000 transplant recipients found that the overall prevalence of anal cancer in that group was similar to the general population at about 0.2%, but that certain subsets, particularly women further out from transplant and patients with HPV-related genital diseases, warranted targeted screening.20PubMed Central. Analysis of >15 000 Solid Organ Transplant Recipients Reveals Nonanal Genitourinary HPV-related Disease as Highest Risk Predictor for Anal Squamous Intraepithelial Lesions/Anal Cancer
Racial and Ethnic Disparities
The burden of anal cancer is not shared equally across racial and ethnic groups. Black individuals in the United States have consistently experienced the highest incidence rates, rising from about 1.5 per 100,000 in 2000–2010 to 2.3 per 100,000 in 2010–2020 for anal adenocarcinoma specifically. White patients saw a more modest climb from 1.2 to 1.5 over the same period, while Hispanic and Asian populations had lower rates throughout.21Journal of Clinical Oncology. Trends in incidence and survival in anal adenocarcinoma: A SEER study of racial and age disparities
The disparities in survival are starker than the disparities in incidence. Black patients with anal adenocarcinoma had a five-year survival rate of about 35% in 2010–2020, compared with about 60% for White patients.22Journal of Clinical Oncology. Trends in incidence and survival in anal adenocarcinoma: A SEER study of racial and age disparities A study focused on women with invasive anal cancer found that non-Hispanic Black women had a significantly greater risk of death than non-Hispanic White women, independent of other prognostic factors. The disparity was sharpest among women diagnosed before age 50.23PubMed. Racial/Ethnic Disparities in Survival Among Women Diagnosed with Invasive Cancer of the Anal Canal A separate analysis of people of color with anal cancer found that they had roughly double the risk of dying and about two and a half times the risk of local recurrence compared with non-Hispanic White patients.24International Journal of Radiation Oncology, Biology, Physics. Disparities in Oncologic Outcomes and Treatment Tolerability Among People of Color with Anal Cancer
These gaps are not fully explained by stage at diagnosis. When the survival data for women were stratified by stage, the disparities between Black and White women disappeared, suggesting that differences in access to early diagnosis play a large role. But Black women were more likely to present with advanced disease in the first place, which points to systemic barriers in screening and health care access rather than biological differences in tumor behavior.25PubMed. Racial/Ethnic Disparities in Survival Among Women Diagnosed with Invasive Cancer of the Anal Canal
Squamous Cell Versus Adenocarcinoma
Most discussions of anal cancer statistics focus on squamous cell carcinoma (SCC), which accounts for the vast majority of cases and is the subtype driven by HPV. But anal adenocarcinoma, though much rarer, is worth knowing about because it behaves differently and carries a worse prognosis. In a study of more than 57,000 cases, anal adenocarcinoma had a median overall survival of about 33 months, compared with roughly 118 months for anal squamous cell carcinoma. Even after adjusting for age, sex, race, stage, and treatment, adenocarcinoma carried a significantly worse outlook.26PubMed. Comparative Survival of Patients With Anal Adenocarcinoma, Squamous Cell Carcinoma of the Anus, and Rectal Adenocarcinoma The difference matters because anal adenocarcinoma does not share the same HPV-driven biology and would not be prevented by HPV vaccination or caught by HPV-based screening approaches.
A related wrinkle in the data is the classification overlap between anal and rectal cancers. Because the anal canal and rectum are continuous, large tumors near the boundary can be difficult to categorize, and some anal squamous cell carcinomas end up coded as rectal cancers in cancer registries. Researchers investigating rectal squamous cell carcinoma in HIV-positive populations found that misclassification was common, though it appeared to occur at similar rates in both HIV-positive and HIV-negative patients.27PubMed Central. Rectal squamous cell carcinoma in immunosuppressed populations: is this a distinct entity from anal cancer? This means that headline statistics for anal cancer may slightly undercount the true burden, especially in registry-based studies.
HPV Vaccination and Its Effect on Anal Cancer
HPV vaccination offers the most promising path to reducing anal cancer incidence over the long term. In a randomized trial among MSM, the quadrivalent HPV vaccine reduced the rate of precancerous anal lesions related to the four vaccine-targeted HPV types by about 50% in the overall study population and by about 78% among participants who were confirmed HPV-negative at the start. The rate of higher-grade precancerous lesions, the type most likely to progress to cancer, was reduced by about 54% overall and 75% in the fully adherent group.28PubMed. HPV vaccine against anal HPV infection and anal intraepithelial neoplasia
Real-world data tells a similar story with an important caveat about age at vaccination. Among women vaccinated before age 17, the risk of developing high-grade anal precancerous lesions or worse was reduced by about 70%. But among women vaccinated between 17 and 32, no significant reduction was observed.29PubMed. Human papillomavirus vaccination and anal high-grade precancerous lesions and cancer-a real-world effectiveness study The finding reinforces what cervical cancer researchers have known for years: HPV vaccines work best when given before a person is exposed to the virus. Once HPV has already established an infection, the vaccine cannot clear it.
Because HPV vaccination programs targeting adolescents only became widespread in the late 2000s, the vaccinated cohorts are still young. The full impact on anal cancer incidence will not show up in population data for years, possibly decades. In the meantime, rates are expected to continue climbing among older adults who were never vaccinated.
Screening and Treating Precancerous Lesions
For people already at high risk, screening offers a way to catch the disease at a precancerous or early stage, when treatment is far more effective. The landmark ANCHOR trial demonstrated that treating high-grade squamous intraepithelial lesions (the precursor to anal cancer) in people with HIV reduced progression to cancer by 57% compared with watchful monitoring alone.30PubMed Central. Treatment of Anal High-Grade Squamous Intraepithelial Lesions to Prevent Anal Cancer Following those results, the U.S. Department of Health and Human Services now recommends anal cancer screening for high-risk individuals, particularly MSM with HIV.31PubMed. Screening for Anal Cancer Among Men Who Have Sex With Men With HIV: Benefits, Harms, and Cost-Effectiveness Analyses
Data from the Netherlands, where anal cancer screening among people living with HIV was introduced in 2007, showed that men diagnosed during screening had improved survival, likely because their cancers were caught at an earlier stage.32The Lancet HIV. Trends in incidence of and mortality after anal cancer diagnosis in people living with HIV in the Netherlands: a 24-year observational cohort study Screening typically involves high-resolution anoscopy, which is the anal equivalent of the colposcopy used for cervical cancer. Unfortunately, access to this procedure is limited: relatively few clinicians are trained in it, and wait times can be long even in major urban centers. For the general population, whose risk is very low, there is currently no recommendation for routine screening.
The Financial Cost of Anal Cancer
Anal cancer treatment is expensive, particularly in the first months after diagnosis. In a study of commercially insured patients in the United States, the average cost associated with the first two years of anal cancer treatment was about $128,000 per patient, with costs heavily front-loaded at roughly $12,800 per month in the first six months before dropping to about $3,700 per month in the subsequent year and a half.33PubMed Central. Health Care Costs of Anal Cancer in a Commercially Insured Population in the United States
For elderly patients on Medicare, the picture looks different. A study of more than 2,200 Medicare patients found an average lifetime cancer-related cost of about $50,000 per patient, with average overall survival after diagnosis of about eight and a half years. Annual costs were higher for men than for women, and they rose with both age and stage at diagnosis. Across all Medicare patients with anal cancer, the total economic burden was estimated at $112 million.34PubMed Central. Total lifetime and cancer-related costs for elderly patients diagnosed with anal cancer in the United States The gap between the commercially insured and Medicare figures reflects differences in how costs are measured, the ages of the populations, and how much private insurers are billed compared with Medicare reimbursement rates.
Treatment strategy also affects cost. For early-stage anal cancer, surgery or ablation costs roughly $29,000 on average, while chemoradiation runs about $46,000 and radiation alone about $49,000. Chemoradiation offered a small survival advantage but at a considerably higher price per additional year of life gained.35PubMed Central. Clinical and economic evaluation of treatment strategies for T1N0 anal canal cancer
Life After Treatment
Survival statistics only capture part of what it means to live with anal cancer. The standard treatment for most non-early-stage cases is chemoradiation, which aims to destroy the tumor while preserving the sphincter and avoiding a permanent colostomy. That goal is achieved in most patients, but not all. In a Danish cohort study, the five-year rate of tumor-related colostomy was about 26%, and an additional 8% of patients needed a colostomy because of treatment-related complications rather than tumor persistence.36PubMed. Cause-specific colostomy rates after radiotherapy for anal cancer: a Danish multicentre cohort study In the ACT II trial, over half of patients who had a colostomy placed before chemoradiation never had it reversed.37PubMed. Tumour- and treatment-related colostomy rates following mitomycin C or cisplatin chemoradiation with or without maintenance chemotherapy in squamous cell carcinoma of the anus in the ACT II trial
Beyond colostomy rates, survivors commonly deal with long-term bowel dysfunction, sexual difficulties, and chronic pain in the treated area. Radiation to the pelvis can damage nerves and tissue in ways that persist for years. These quality-of-life issues are often under-reported in statistical summaries that focus on survival and disease-free intervals, but they matter enormously to patients. The relatively good survival for squamous cell carcinoma, with a median of nearly 10 years, means many people live for a long time with these side effects.
The overall statistical picture of anal cancer is one of a disease that is rare but growing less so, heavily shaped by HPV and immune status, marked by real disparities in who gets it and who survives it, and increasingly amenable to prevention through vaccination and screening. For the populations most at risk, the numbers have already reached the point where organized public health responses are justified and, in some countries, underway.