From 1980 through 2006, the proportion of deaths attributable to AIDS cancers declined sharply in US AIDS patients. But the proportion attributed to non-AIDS cancers rose more than 4 times in this study, which used a new method to assess cancer mortality.

The arrival of combination antiretroviral therapy around 1996 lowered AIDS death rates sharply in the United States. But the risk of cancer and death from cancer remains high in people with AIDS. Researchers tried to get a better estimate of cancer death rates in US patients with AIDS by using population-attributable risk methods, which do not rely on death certificates, because death certificates may be inaccurate.

Data for the analysis came from a US population-based record-linkage study that identified new cancer diagnoses and cancer deaths in 377,364 people with AIDS from 1980 through 2006. People in this cohort had up to 5 years of follow-up after their AIDS diagnosis. The researchers compared mortality in people with and without cancer to calculate cancer-attributable mortality in three periods: 1980-1989, 1990-1995, and 1996-2006.

Overall mortality dropped across the three study periods for these AIDS patients but remained higher for people with cancer than for those without cancer. In 1996-2006, 88.3% of deaths in people with an AIDS cancer could be attributed to their cancer. In the same period, 87.1% of deaths in people with a non-AIDS cancer could be attributed to that non-AIDS cancer.

The fraction of all deaths in these AIDS patients that could be attributed to an AIDS cancer (that is, the population-attributable risk) fell significantly from 6.3% in 1980-1989 to 3.9% in 1996-2006. But the fraction attributable to non-AIDS cancers rose significantly from 0.5% in 1980-1989 to 2.3% in 1996-2006.

“With a decline in overall mortality, the proportion of all deaths attributable to [non-AIDS cancers] has increased,” the researchers conclude, suggesting that “these results highlight the need for improved cancer prevention and treatment.”

By Mark Mascolini

Source: Edgar P. Simard, Ruth M. Pfeiffer, Eric A. Engels. Mortality due to cancer among people with AIDS: a novel approach using registry-linkage data and population attributable risk methods. AIDS. 2012; 26: 1311-1318.

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