HPV is not cancer. Human papillomavirus (HPV) is a common sexually transmitted infection, and most people who get it never develop cancer. But certain strains of HPV can cause cancer if the infection persists for years without being cleared by the immune system. About 80% to 90% of HPV infections resolve on their own within two years. The ones that don’t are where the risk begins.
How HPV Leads to Cancer
There are over 200 types of HPV, and they fall into two broad categories: low-risk types that cause genital warts, and high-risk types that can trigger cancer. HPV types 16 and 18 are the most dangerous, responsible for roughly 76% of cervical cancers worldwide.
When a high-risk HPV infection lingers, the virus produces two proteins that hijack your cells’ built-in safety systems. One protein destroys a molecule your cells use to stop damaged DNA from replicating. The other disables a separate brake on cell division, forcing cells to keep multiplying even when they shouldn’t. Together, these proteins turn off the two main controls that prevent normal cells from becoming cancerous. Over time, the unchecked growth creates precancerous changes that can eventually become invasive cancer if left undetected.
This process is slow. For someone with a healthy immune system, a persistent HPV infection typically takes 15 to 20 years to progress to cancer. For people with weakened immune systems, that window can shorten to 5 to 10 years.
Which Cancers HPV Causes
HPV doesn’t just cause cervical cancer. It’s linked to cancers in six areas of the body, and the percentage of cases driven by the virus varies by site:
- Cervix: 91% of cases caused by HPV
- Anus: 91% (93% in women, 89% in men)
- Vagina: 75%
- Oropharynx (back of the throat): 70% (72% in men, 63% in women)
- Vulva: 69%
- Penis: 63%
Throat cancer linked to HPV has been rising sharply in recent decades, particularly in men. Unlike cervical cancer, there’s no routine screening test for HPV-related throat, anal, or penile cancers, which means these often aren’t caught until symptoms appear.
Why Most HPV Infections Don’t Become Cancer
Your immune system clears the vast majority of HPV infections before they can do lasting damage. Up to 90% of infections are gone within two years, often without the person ever knowing they were infected. The virus doesn’t enter your bloodstream. It infects surface cells in the skin or mucous membranes, and in most cases the immune response eliminates it completely.
The infections that persist are the concern. Certain factors make clearance less likely: a weakened immune system (from HIV, organ transplant medications, or other conditions), smoking, and having multiple HPV types at once. Even with a persistent infection, cancer is not inevitable. The infection must remain active for years, the precancerous cell changes must go undetected, and those changes must progress through several stages before becoming invasive.
HPV Affects Men Too
HPV is often framed as a women’s health issue because of cervical cancer, but men face real risks. HPV causes roughly 72% of oropharyngeal cancers in men and 89% of anal cancers in men. Penile cancer is rarer, but 63% of cases are HPV-related. The challenge for men is that no standard screening tests exist for any of these cancers. There’s no equivalent of a Pap test or HPV test for the throat, anus, or penis in routine clinical practice. This makes vaccination and awareness especially important.
How Screening Catches Problems Early
Cervical cancer screening is the main tool for detecting HPV-related precancers before they progress. Current guidelines from the U.S. Preventive Services Task Force recommend starting Pap tests at age 21, repeated every three years through age 29. From age 30 to 65, you can choose between an HPV test every five years, a combined HPV and Pap test every five years, or a Pap test alone every three years. The American Cancer Society recommends starting HPV testing at age 25 and repeating it every five years through age 65.
These screening intervals exist because cervical cancer develops slowly. Regular testing gives doctors years to catch abnormal cell changes and remove them before they become cancerous. After age 65, screening can usually stop if previous results have been consistently normal.
Vaccination Prevents Most HPV Cancers
The HPV vaccine targets the high-risk strains most likely to cause cancer, including types 16 and 18. Long-term studies show the vaccine is about 91% effective at preventing high-risk HPV infections, with protection lasting well beyond five years. It’s recommended for everyone starting at age 9 through 26, and it works best when given before any exposure to the virus.
The vaccine doesn’t treat existing infections or precancerous changes. Its power is entirely preventive. For people already infected with one HPV type, the vaccine still protects against the other types it covers. Adults between 27 and 45 who weren’t vaccinated earlier can discuss catch-up vaccination with their provider, though the benefit decreases with age since most people have already been exposed to at least some HPV strains by then.
Between vaccination and screening, most HPV-related cancers are preventable. The virus is extremely common, but cancer from HPV is not. The gap between infection and cancer is wide, and at nearly every point along that path, there’s an opportunity to stop the progression.