Anal cancer burden high among people with HIV
medwireNews: People with HIV infection are nearly 20 times more like to develop anal cancer than those in the general population, study findings indicate.
Men who have sex with men (MSM), older individuals, and people with AIDS had the greatest risk, report Vivian Colón-López (University of Puerto Rico, San Juan) and colleagues.
The results arose from an analysis of HIV and cancer registries in eight US states and Puerto Rico between 1996 and 2012.
During this time, 1567 of 447,953 people with HIV were diagnosed with anal cancer, which corresponds to an incidence rate of 50.7 cases per 100,000 person–years and a standardized incidence ratio (SIR) of 19.1.
Subgroup analysis showed that crude incidence rates were highest among MSM (89.0 per 100,000 person–years) and those who were White (80.3 per 100,000 person–years), while individuals with AIDS (70.0 per 100,000 person–years) were 3.8 times more likely to develop anal cancer than those without AIDS.
In addition, incidence generally increased with age, and peaked among participants aged 45–59 years, at 63.0 per 100,000 person–years.
However, when anal cancer incidence among people with HIV was compared with that of the general population, the youngest participants (<30 years) had the highest SIR, at 72.4, followed by MSM and White individuals, at 38.7 and 37.9, respectively.
The researchers also found that anal cancer incidence within the cohort changed over time. It increased steeply from 1996 to 2000 (annual percentage change [APC]=32.8%), reached a plateau between 2001 and 2008 (APC=1.4%), and declined from 2008 to 2012 (APC=−7.2%).
This decline “is encouraging and may reflect delayed benefits of increasing use of [highly active antiretroviral therapy],” Colón-López et al write in the Journal of Clinical Oncology.
“However, because anal cancer incidence increases with age, the overall burden of patients with this disease may start to increase again with the aging of the US HIV population,” they add.
At 5-years post HIV or AIDS diagnosis, the majority of individuals, grouped by age (<30, 30–44, 45–59, and ≥60 years) and sex (women, MSM, and other men), had a cumulative incidence of anal cancer below 0.20%.
However, the rate was 0.32–0.33% in MSM with HIV but not AIDS aged 45 years and older, and 0.29–0.65% in MSM with AIDS aged 30 years and older.
If a lower cumulative incidence limit of 0.25% was set to target candidate populations for anal cancer screening, only these two groups would need to be included, Colón-López and co-authors point out.
They say: “Thus, the current results suggest that any programs to screen for anal cancer among people with HIV infection would be focused most effectively on certain high-risk subgroups.”
The team adds that “[a]pproaches for anal cancer screening and prevention currently are being evaluated among people with HIV infection.”
By Laura Cowen
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