Understanding HPV and Cancer

Table of Contents 

• What is HPV?
• How is HPV transmitted?
• How does HPV cause cancer?
• How do I know if I have high-risk HPV?
• How can I limit my risk of cancer from HPV?

What is HPV?

Human papillomavirus (HPV) is a highly common group of viruses of which there are more than 200 types. Most types of HPV cause common warts and are spread through non-sexual contact, such as skin-to-skin touching or contact with contaminated surfaces. Approximately 40 types of HPV can infect the genital area (vulva, vagina, cervix, penis, scrotum, anus), mouth, or throat, and are spread through sexual contact (CDC, 2021). Sexually transmitted HPV the most common sexually transmitted infection in the world- in fact, 80% of sexually active individuals will experience an HPV infection at some point during their lifetime (NFID, 2022). While most sexually transmitted HPV infections clear themselves over time, some can persist in the body and cause health problems. Some types of sexually transmitted HPV cause genital warts. While unpleasant, this form of HPV is considered low-risk as it is not linked to cancer or other health problems. However, certain types of sexually transmitted can lead to cancer, and are also known as high-risk HPV (NIH, 2021).  This article will explain how HPV is linked to cancer and how to reduce your risk of complications from high-risk HPV.

How is HPV transmitted?

Sexually transmitted HPV is spread through having vaginal, anal, or oral sex with someone who has the virus, or having close skin-to-skin contact. This means that HPV can sometimes still be transmitted even if a condom or other barrier is used, or if intercourse does not occur (NIH, 2021).  A person with HPV can also transmit the virus even if they are not having any symptoms. This is why HPV is so common- most people are not aware that they have the virus, and pass it to others unknowingly. Furthermore, there are limited tests available for HPV- there are currently no approved HPV tests for men, and most tests for women only check for high-risk types (NIH, 2021). 

Most of the time, the body’s immune system clears HPV from the body within two years of infection, and nearly everyone who has sex will have HPV at some point in their life (Radboud UMC, 2022). This is why there’s no need to feel ashamed or scared if you find that you have HPV- it is very common and sometimes difficult to detect. Furthermore, although there is no cure for HPV, most people will naturally clear the infection without any treatment. 

How does HPV cause cancer?

As mentioned, the body’s immune system often naturally cures high- and low-risk HPV within a few years of being infected. However, in some cases, the infection does not clear and persists in the body. When high-risk HPV remains in the body, it can infect other body cells and cause changes to cell DNA. Over time, this can make cells begin to grow uncontrollably, which can lead to cancer (CDC, 2021). 

What types of cancer does HPV cause?

Cervical cancer is the main cancer that is linked to high-risk HPV. Most cases of cervical cancer are caused by HPV. Additionally, most cancers of the vagina, vulva, penis, and anus are also caused by HPV, as well as most oropharyngeal cancers (such as the tonsils and base of the tongue). HPV presents a cancer risk in both women and men, which is why preventing HPV infections should be a priority for everyone (CDC, 2022).

Number of cancers caused by HPV in the US, 2020

Source: CDC

What types of high-risk HPV cause cancer?

There are approximately 14 high-risk HPV types associated with cancer. However, the majority of HPV-related cancers are caused by types 16 and 18. HPV types 16 and 18 are responsible for 70% of cervical cancers and precancerous lesions. Other high-risk types of HPV are: 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 66, and 68 (NIH, 2021).

How do I know if I have high-risk HPV?

Unlike low-risk HPV that can cause visible genital warts, high-risk HPV has no symptoms until after cell changes or cancer occurs. HPV-related cell changes to the cervix are most commonly checked with a Pap smear, a test in which a sample of cells are taken from the cervix to check for cancer or precancerous cell changes (NIH, 2021). In recent years, HPV tests have become more widely used for checking infections of the vulva, vagina, or cervix. These tests can detect high-risk HPV infections, but not whether cell changes have occurred. This means that if the result of an HPV test is positive, a follow-up Pap smear is required. For more information on the difference between HPV testing and Pap smears, click here. Unfortunately, there is currently no approved HPV test for infections of the penis, anus, mouth, or throat. This is why prevention of high-risk HPV is beneficial for everyone.

Homed-IQ now offers an at-home HPV Tests for Women. This preventive health test checks for high-risk HPV types using a vaginal swab and can be performed in the privacy of your home. Home HPV testing may be useful for individuals who want to know if they are currently infected with high-risk HPV but are not eligible for government screening, or face other barriers accessing HPV-related testing. However, HPV testing cannot diagnose cervical cell changes or cancer, and a follow-up Pap smear is always required after a positive HPV test.

How can I limit my risk of cancer from HPV?

The most effective way to prevent high-risk HPV infections in both men and women is getting vaccinated against HPV. The HPV vaccine protects against the most high-risk forms of HPV, including types 16 and 18, as well as the most common strains that cause genital warts (CDC, 2021). HPV vaccination is the most effective if it is administered before you start having sex, but even if you are already sexually active it is still a good decision to get vaccinated. The CDC and the Dutch Public Health Institute (RIVM) recommends that men and women before age 26 are vaccinated (CDC, 2022) (RIVM, 2022). Vaccination is not recommended for most people older than 26 as HPV infection in this age range provides less benefit. However, adults 27-45 years may decide to get the HPV vaccine after speaking to their GP.

While government screening programs in different countries may only offer HPV vaccinations to women, men should consider vaccination to lower their own risk of cancer and prevent spreading HPV to female partners. In addition to vaccination, safe sex practices such as condom use reduce the risk of HPV, although they do not provide perfect protection (CDC, 2022). 

Finally, getting screened is an important way to prevent cervical cancer or catch it in an early stage. While testing guidelines vary by country, it is recommended to follow all local guidelines for screening using either HPV testing or Pap smears. In the future, it is hoped that deaths from HPV-related cancers can be significantly reduced through population-wide vaccination and regular screening.