Progress in cancer prevention
cancer screening Cancer anal cancer

Progress in cancer prevention

Dr. Talia Henkle
Dr. Talia Henkle

In 10 seconds? New data shows that screening and treatment procedures can successfully prevent the formation of anal cancer.

Wow, that’s good news! How can anal cancer be prevented? It’s pretty much common knowledge that cancer is easier to treat the earlier it is found. That’s why researchers are always looking for new ways to catch cancer as early as possible (AKA new cancer screening methods).  But cancer screening is not as straightforward as it may seem. Many considerations need to be taken into account before a new screening procedure is recommended.

Nice touch with the suspense but let’s cut to the chase… Fine. To quote the guy talking to himself in the mirror at the gym, Are the pains worth the gains? More precisely, who should be screened? Cancer screening involves time, money, and sometimes an uncomfortable procedure. Clinicians want to be sure that the people they screen will benefit from undergoing the hassle. Next, how accurate are the screening results? False positive and false negative results both can have detrimental effects on patient well-being. Moving on, even if you get reliable screening results, what medical decisions should be made? Should patients be treated right away, which could involve uncomfortable procedures or medication side effects? Or should the patients continue to be monitored to see if the issue resolves itself?

Where are you going with this? Bear with me. Researchers have finally gathered robust evidence to support an anal cancer screening and treatment procedure amongst people living with the Human Immunodeficiency Virus (HIV). For context, anal cancer is caused by Human Papillomavirus (yes, the same virus that causes cervical cancer!). In the general population, anal cancer is rare, but it is more common among certain immunosuppressed populations like those living with an HIV infection or those who have received organ transplantation.

So, why is this procedure better? Does it catch anal cancer early? Similarly to cervical cancer, after HPV infection, pre-cancerous lesions (AKA patches of cells that are starting to develop cancerous characteristics but are not yet considered cancer) can be detected before anal cancer develops. Anal cancer screening procedures were modeled after cervical cancer screening methods, which have been key in bringing down cervical cancer rates (Check out my digest on the topic here!). However, there had been no robust studies done to determine what should be done if patients were found to have an anal pre-cancerous lesion. Should they be treated right away? Or should they be closely monitored, in case the lesion clears up on its own?

OK, and do we have the answers to these questions? Yes. Between 2014-2021, researchers identified about 4500 individuals living with HIV who had pre-cancerous anal lesions. They divided the patients into two groups, one that received treatments (such as ablative procedures or topical imiquimod treatments) and one that was not treated but was re-screened every 6 months. They have found that patients who were treated were about 60% less likely to progress to anal cancer than those who were actively monitored.

Treatment of pre-cancerous anal lesions lowers cancer risk Source: Palefsky AM, et al. N Engl J Med. 2022;386(24)

So why should I care about this? These data provide solid evidence to support the screening of at risk-populations for anal cancer as well as early treatment interventions for those with pre-cancerous lesions. This is an awesome example of how researchers are having success designing rational cancer prevention methods. Furthermore, it provides data to show that these methods work to save patient lives!

What else can prevent cancer formation?

It’s exciting when science can actually provide definitive answers to this question! The biggest step anyone can take to prevent anal cancer is receiving the HPV vaccine (FDA approved up to age 45 for both men and women).

Beyond that, since HIV infection increases the risk, practice safe sex and attend regular HIV screening to minimize your risk (for all adults! 23% of new HIV diagnoses are among heterosexual individuals).

Lastly, quit smoking! The researchers noted that smoking was common among patients with pre-cancerous lesions, and due to its connection with various other cancers, they suggested that quitting smoking could perhaps lower anal cancer risk.

Dr. Talia Henkle has distilled 3 research papers saving you 10.5 hours of reading time.

The Science Integrity Check of this 3-min Science Digest was performed by Flávia Oliveira Geraldes.

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