January 19, 2009
Since the appearance of AIDS in the early 1980s, the United States military has been collecting health-related information on affected personnel and their family members. So far, data on nearly 4,500 HIV positive people has been collected. Analyses of this data set can be a powerful tool to better understand changes in HIV-related conditions over several decades.
Recently, military medical personnel used this data set to investigate trends in cancers and found a significant shift in the type of cancers over time. The implications of their findings are discussed later in this report.
Researchers focused their analysis on the period spanning 1984 and 2007. Here is the average profile of participants at the time they were diagnosed with HIV infection:
Over a 20-year span, about 10% of the group, or 446 people, developed cancer. Most of the cancers (68%) occurred before 1996 and were related to AIDS (Kaposi's sarcoma and so on). In general, AIDS-related cancers became less common after 2001. Indeed, rates of cancers unrelated to AIDS have significantly increased in the present era compared to the time before HAART, as outlined below:
Cancers that were unrelated to AIDS and that occurred during the study were as follows:
Of these cancers, only anal cancer rates increased in a statistically significant manner between 1984 and 2007.
Overall, the study team calculated that the risk of cancers unrelated to AIDS was twice as high in HIV positive people compared to healthy HIV negative people. Anal cancer was 13 times more common in HIV positive men than in HIV negative men of a similar age.
The military researchers noted that the older a person was in this study, the greater his or her risk for developing cancer. This makes sense because people's immune systems slowly degrade with age. Another finding was that Black people were less likely to develop skin cancer than White people.
There did not seem to be any relation between CD4+ counts and the risk of developing cancers unrelated to AIDS.
During the study about 34% of participants died. Among people who experienced non-AIDS-related cancer, 40% died. For people with these cancers, the following proportions died a certain time after their cancer was diagnosed:
Survival was generally better in participants who developed AIDS-related cancers.
There may be many reasons for the increase in cancers unrelated to AIDS, as follows:
It is noteworthy that many of the cancers (nearly 80%) unrelated to AIDS in this study occurred when CD4+ counts were above the 350-cell level. This finding suggests that in addition to HAART other steps are needed to help protect HIV positive people from these cancers. Such steps might include the following:
Although long-term HIV infection is increasingly associated with a heightened risk for certain cancers, the actual number of people developing such cancers is relatively small. And, as more research is done on cancers unrelated to AIDS, perhaps more ways of preventing these cancers will become available.
Next up in CATIE News: a British study on cancer uncovers a surprising and potentially disturbing trend.