# “I just assumed that was the same as colon cancer.” Lack of knowledge about anal HPV infection, anal cancer, and anal cancer screening in older MSM: a qualitative study

**Authors:** Catherine Nguyen, Danielle Miguel, Christopher Scott Weatherly, Sahai Burrowes, Jessica Lopez Jimenez, Ryan Gonzalez, Joel M. Palefsky, Alexandra L. Hernandez

PMC · DOI: 10.1186/s12889-025-25202-w · BMC Public Health · 2025-11-21

## TL;DR

Older men who have sex with men, especially those living with HIV, have significant knowledge gaps about anal HPV infection, anal cancer, and the difference between anal and colorectal cancer screening.

## Contribution

This study identifies specific knowledge gaps and misconceptions about anal cancer and screening among older MSM, including confusion with colorectal cancer screening.

## Key findings

- Participants often believed colonoscopy screens for anal cancer, which it does not.
- Many were unaware of the HPV vaccine or the link between HPV and anal cancer.
- Healthcare providers were also perceived as lacking knowledge about anal cancer.

## Abstract

Antiretroviral treatment has allowed people living with HIV (PLWH) to live longer lives. A high proportion of PLWH are ≥ 50 years of age and identify as men who have sex with men (MSM); MSM who are living with HIV (MSMLWH) are at increased risk for anal cancer and anal human papillomavirus (HPV) infection, its causal agent. We explored knowledge of anal cancer, HPV infection and anal cancer screening using qualitative methods.

Five focus group discussions were conducted with 21 MSMLWH and 11 MSM not living with HIV, ages 50–75 years, in San Francisco, California. Data were analyzed using a thematic analysis approach employing a mix of inductive and deductive codes.

We identified three main themes and eight sub-themes that characterized participants’ understanding of HPV and anal cancer: (1) Lack of knowledge, including lack of knowledge of HPV/anal cancer; lack of knowledge of HPV vaccine; lack of knowledge that colonoscopy does not screen for anal cancer; and a perceived lack of knowledge about anal cancer in health care providers; (2) Personal experience with HPV and anal cancer; and (3) Awareness of HPV and anal cancer, including general awareness and awareness through celebrities or the media. There were important knowledge gaps among MSM aged 50 and older about HPV infection and anal cancer, including a misunderstanding that colorectal cancer screening can detect anal cancer. Increasing health provider knowledge and engaging the media or celebrities in health education campaigns could be effective strategies to increase awareness.

The recently released federal screening guidelines for anal cancer recommend screening all MSM and transgender women over the age of 35 who are living with HIV. Public health professionals should be aware of knowledge gaps among older MSM that pose barriers to screening. Given that our participants are in the age group where colorectal cancer screening is routinely recommended, our findings suggest that awareness of anal cancer risk may not be sufficient to motivate screening if patients believe they have already been screened. Education campaigns should also teach the difference between anal cancer screening and colorectal cancer screening.

## Linked entities

- **Diseases:** anal cancer (MONDO:0003199), colorectal cancer (MONDO:0005575)

## Full-text entities

- **Diseases:** anal cancer (MESH:D001005), colon cancer (MESH:D015179), anal HPV infection (MESH:D030361)

## Full text

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## References

9 references — full list in the complete paper: https://tomesphere.com/paper/PMC12639761/full.md

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Source: https://tomesphere.com/paper/PMC12639761