AIDS-related cancer and severity of immunosuppression in persons with AIDS.

BACKGROUND

The incidence of Kaposi sarcoma, non-Hodgkin lymphoma, and cervical cancer has been declining among persons with AIDS. We investigated the association between cancer risk and CD4 cell count among such persons.

METHODS

Data from US AIDS registries were linked to local cancer registry data. Cancer incidence per 100,000 person-years was determined for the 4-27 months from the onset of AIDS from January 1, 1990, through December 31, 1995--before highly active antiretroviral therapy (HAART) became available--and from January 1, 1996, through December 31, 2002. The relationships between CD4 count at AIDS onset and cancer incidence were assessed by proportional hazards models.

RESULTS

Among 325,516 adults with AIDS, the incidence of Kaposi sarcoma was lower in 1996-2002 (334.6 cases per 100,000 person-years) than in 1990-1995 (1838.9 cases per 100,000 person-years), and the incidence of non-Hodgkin lymphoma followed a similar pattern (i.e., 390.1 cases per 100,000 person-years in 1996-2002 and 1066.2 cases per 100,000 person-years in 1990-1995). In 1996-2002, for each decline in CD4 cell count of 50 cells per microliter of blood, increased risks were found for Kaposi sarcoma (hazard ratio [HR] = 1.40, 95% confidence interval [CI] = 1.33 to 1.50), for central nervous system non-Hodgkin lymphoma subtypes (HR = 1.85, 95% CI = 1.58 to 2.16), and for non-central nervous system diffuse large B-cell lymphoma (HR = 1.12, 95% CI = 1.04 to 1.20) but not for non-central nervous system Burkitt lymphoma (HR = 0.93, 95% CI = 0.81 to 1.06). Cervical cancer incidence was higher in 1996-2002 (86.5 per 100,000 person-years) than in 1990-1995 (64.2 per 100,000 person-years), although not statistically significantly so (relative risk [RR] = 1.41, 95% CI = 0.81 to 2.46). After adjustment for age, race, and sex or mode of HIV exposure, the risks for Kaposi sarcoma (RR = 0.22, 95% CI = 0.20 to 0.24) and for non-Hodgkin lymphoma (RR = 0.40, 95% CI = 0.36 to 0.44) were lower in the period of 1996-2002 than in 1990-1995. Similar relationships of these cancers to CD4 count were observed for 1990-1995.

CONCLUSIONS

Both before and after HAART was available, CD4 count was strongly associated with risks for Kaposi sarcoma and non-Hodgkin lymphoma but not for cervical cancer and Burkitt lymphoma. The decreasing incidences of most AIDS-associated cancers in persons with AIDS during the 1990s are consistent with improving CD4 counts after HAART introduction in 1996.