Does anal sex increase the risk of colon cancer?

Any link between sex and types of cancer comes down to human papillomavirus (HPV), a group of viruses with some that are transmitted through sex. This includes vaginal, oral, and anal sex.

Some forms of cancer are strongly related to HPV, including anal cancer. Colorectal cancer is not one of these.

A 2022 study that reviewed a claims database in Taiwan indicated that HPV is associated with an increased risk of colorectal cancer.

However, a small 2014 study that evaluated a group of colon cancer tissue samples and a group of rectal cancer collected from people in Iran did not indicate the same conclusion.

More research is needed to help scientists get a clearer idea of the relationship between HPV and this form of cancer.

There is a lack of evidence to suggest that anal sex can increase the risk of colorectal cancer.

HPV infections are common and typically go away without causing cancer. However, some forms of HPV can lead to a cancer diagnosis.

Anal cancer is different from colorectal cancer. Colorectal cancer affects the colon and the rectum, parts of the digestive system inside the body. Anal cancer affects the anus, which is the opening at the end of the rectum.

The American Cancer Society (ACS) lists HPV infection as the primary risk factor for anal cancer. It also considers having receptive anal sex as a risk factor.

One 2022 study reviewing positioning associated with sexual practices of men who have sex with men and transgender women indicated that people who received anal sex were more likely to have HPV than those who were only the insertive partner.

This increased risk is due to how thin the lining of the anus is. It becomes damaged easily, leaving the body open to infection. The anus lining also lacks the natural lubrication of the vagina or mouth.

However, when it comes to colorectal cancer, the evidence is less clear.

One 2019 study involving 6,596 women did not find a significant difference in the risk of colorectal cancer between those who received anal intercourse and those who did not.

People who are the insertive partner during anal sex are less at risk from STIs than the receiving partner.

As stated above, the anus is more prone to infection than other parts of the body, such as the penis. It also has a larger surface area.

Insertive partners can still contract HPV from a receiving partner because HPV is transmitted through skin-to-skin contact. A person can transfer HPV even if a partner does not ejaculate.

One older study involving teenage men who had sex with men showed that HPV rates were higher in those who had insertive anal sex with more people compared with those who had had no prior insertive anal sex.

A number of factors can increase a person’s risk of developing colorectal cancer. It is important to note that people can change or manage some of them but are not able to do that with others.

These risk factors include:

Colorectal cancer is more common after age 50.

Some racial and ethnic groups experience higher rates of colorectal cancer than others. In the United States, people who are American Indian, Alaska Native, and African American have the highest rates. Worldwide, Ashkenazi Jews are another group with a high risk of developing the condition.

Research suggests that while some of this increased risk may be due to contributing factors like differences in access to care and other socioeconomic situations, there are still some disparities after accounting for this.

While it is not possible to prevent all colorectal cancer diagnoses, there are steps people can take to help reduce their risk.

Lifestyle adjustments that may help include:

• maintaining a moderate body weight
• staying physically active
• following an eating pattern that is high in plant-based foods and low in red and processed meats
• limiting alcohol intake if a person consumes alcohol
• not smoking

Colorectal cancer screening can also help doctors spot abnormal growths and remove them before they can turn cancerous. It can also help doctors find cancer in its early stages before symptoms appear, which may be easier to treat.

The CDC advises that adults receive regular screenings starting at age 45.

It is uncertain whether anal sex is a risk factor for colorectal cancer.

Anal sex is a risk factor for anal cancer. This is largely due to the risk of contracting an HPV infection, which is a cause for a significant number of anal cancer diagnoses.

There is not an equal amount of evidence to suggest this is the same for colorectal cancer, and major cancer institutions do not list anal sex as one of the risk factors.

For people who are having anal sex, using condoms and the correct lubrication can help reduce the risk of contracting an infection and allow partners to have a safe and pleasurable time.