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.