Cytology screening every three years among men who have sex with men (MSM) currently over the age of 35, plus cytology screening every two years for those who become newly eligible for screening at age 35 could help cut anal cancer deaths by up to 65%.
This is according to s study – “Screening for Anal Cancer Among Men Who Have Sex With Men With HIV: Benefits, Harms, and Cost-Effectiveness Analyses” by Ashish A. Deshmukh, Haluk Damgacioglu, Keith Sigel, et al – that was published in the Annals of Internal Medicine.
There are two types of anal cancer screening tests – cytology, which looks at cells under a microscope; and HPV testing, which looks for strains of the human papillomavirus that are known to cause cancer. These tests are similar to those performed for cervical cancer.
“Anal cancer is preventable,” Deshmukh said. “Our study shows that screening for anal cancer has the potential to reduce incidence and death rates by 65% over the lifetime – that’s substantial.”
And yet the researchers noted that there’s a major knowledge gap, “and our objective was to address that,” Deshmukh said.
Deshmukh noted that once you take into account the two types of screening, the various ages at which screening might start and the different groups that could be considered for screening, there are dozens of possible combinations.
This work builds off of guidelines written by the International Anal Neoplasia Society, which Deshmukh also helped to write. Those guidelines offer five screening modalities but no specific recommendations on which of those are superior options.
The new paper considered cost-effectiveness and harm versus benefit – in other words, the number of tests that would need to be performed to prevent one case of cancer or to extend one life year. It focused on men who have sex with men with HIV, the group at highest risk of anal cancer.
The study found that cytology screening every three years among members of this group currently over the age of 35 plus cytology screening every two years for those who become newly eligible for screening at age 35 provides the highest value.
The cost-effectiveness and harm-versus-benefit ratio would likely be different for other groups, Deshmukh noted. In addition, this recommendation could change in the future as more young adults get the HPV vaccine, since the human papillomavirus is responsible for the majority of anal cancers.
“Screening is associated with a lot of anxiety and false positives,” Deshmukh said. “So what we’re doing is identifying certain strategies that are associated with a substantial number of false positives over an individual’s lifetime versus certain strategies that may not cause as much harm and anxiety and identifying specific strategies that reduce those harms but maintain the cancer prevention benefit.”
In the end, “anal cancer screening among MSM with HIV aged 35 years or older is cost-effective, but value-based prioritization of strategies is needed to optimize screening use,” the researchers ended.
