In the HAART era, it is generally agreed that the incidence of most AIDS-defining cancers has declined dramatically – with the exception of Non Hodgkins Lymphoma. However, the incidence of non-AIDS-defining cancers has been the subject of some debate since the National Cancer Institute published a study last year which found that other cancers have not become much more prevalent as people with HIV in resource-rich countries live longer, despite other studies suggesting this is the case. Additionally, they asserted that non-AIDS-defining cancers were unrelated to CD4 counts.
Adding to the debate was an oral presentation at the 11th Retroviruses Conference in San Francisco on Tuesday, from Patel and colleagues, who asserted not only that non-AIDS-defining cancers were more common, but that they were related to lowest ever, or nadir, CD4 counts.
These Chicago-based researchers identified the five most common non-AIDS-defining cancers in two major cohorts - 6700 patients at their two largest clinics and a further 5400 members of the multicentre HIV Outpatient Study (HOPS) cohort - and compared them with the general population to determine the incidence and relative risk of these cancers in people with HIV for the years 1992 to 2002.
The five non-AIDS-defining cancers were lung, head/neck, Hodgkins disease, anorectal, melanoma. Among the HOPS cohort, in analyses adjusted for age, race, smoking, and gender, incidence of four cancers was significantly greater than expected compared with the general popuation: lung (Relative Risk = 2.13 [95% CI:1.06, 4.27]), Hodgkins disease (RR = 4.58 [95%CI: 3.10, 6.77]), anorectal (RR = 10.13 [95% CI: 7.48, 13.72]), and melanoma (RR = 2.99 [95% CI: 1.71, 5.22]).
Among Chicago clinic patients, all five cancers were significantly increased in the multivariate analysis: lung (RR = 3.63 [95% CI: 2.18, 6.05]), Hodgkins disease (RR = 77.43 [95% CI: 19.37 - 309.55]), anorectal (RR = 5.03 [95% CI: 4.76, 5.33]), melanoma (RR = 4.10 [95% CI: 9.39 - 152.70: note these confidence intervals are reported in the abstract]), head/neck (RR = 9.96 [95% CI: 2.49 - 39.79.
When looking at factors associated with these cancers, the researchers found that those with cancer had a significantly lower mean nadir CD4 count – strongly suggesting that immune suppression plays an important role in the pathogenesis of these cancers. Additionally, both lung and head/neck cancers were significantly associated with being a current or past smoker. There was also a trend to older age in those with cancer, which is similar to the general population.
Further information on this website
Outcome of lung cancer in HIV-positive patients improved since HAART, but prognosis still poor - news story
HAART positively affects survival of AIDS-related non-Hodgkins lymphoma - news story
No higher risk of non-AIDS cancers in advanced HIV disease, says US National Cancer Institute - news story
Patel P. et al. Incidence of Non-AIDS-defining Malignancies in the HIV Outpatient Study 11th CROI, San Francisco, abstract 81, 2004.