(PDF of entire published article attached)
This large study published in AIDS (2001 March 30; 15(5):629-633) reports that both KS and NHL incidence have declined since June 1996 (the advent of HAART) but that the incidence of KS has declined more than NHL.
|Time period||Incidence/1000 person-years (95% CI)|
|July '94 -June '96||5.2|
|Jan '96 -Dec '98||1.9|
|July '94 -June '96||7.5|
|June '96-Dec '98||4.3|
Australian researchers report:
This study finds decreasing incidence rates of both NHL and KS in people with HIV since the introduction of potent anti-retroviral therapies. For NHL, incidence had been increasing prior to 1996, and this increase masked the decrease since the introduction of the new HIV therapies when long-term trends were considered. The increase in NHL incidence in the early epidemic, which was also seen for KS, may have been related to increasing immune deficiency of the cohort. This study also confirms at a population level the previously described decreases in the incidence of KS during the 1990s. This decrease began before the introduction of the new therapies. KS has decreased in incidence by far more than NHL, so that NHL is now the most common AIDS-associated cancer in Australia.
It is unclear why rates of NHL appear to be decreasing more slowly than other AIDS-associated illnesses, but there are at least three possible explanations. First, unlike KS, NHL does not appear to be due to a specific infective agent, so partial immune restoration may be less effective in prevention. Second, NHL occurs at a less severe degree of immune deficiency than most other AIDS-associated illnesses. Third, there is evidence that chronic stimulation of the immune system is a risk factor for AIDS-related NHL, and potent combination antiretroviral therapy may be only partially effective at reversing this immune stimulation [14,15]. (Editorial note from Jules Levin: does this make a case towards earlier treatment for HIV to avoid immune decline and active viral stimulation which treatment inhibitis? Perhaps this is one consideration among many. Also to be considered, is what's the risk of getting NHL whether therapy is started earlier or later?)
In summary, the era of potent combination antiretroviral therapy has been associated with an acceleration in already declining incidence rates of KS in people with HIV, and a decline in incidence rates of NHL. The magnitude of reduction in NHL rates has not been as great as the reduction in rates of KS, and of most other opportunistic infections in people with AIDS, so it is likely that NHL will comprise an increasing proportion of AIDS-associated illnesses.