Immune deficiency and risk for malignancy among persons with AIDS

Abstract

Background: People with AIDS have an elevated risk for cancer. We studied the relationship between cancer risk and AIDS-related immunosuppression as measured by CD4 count at AIDS onset.

Methods: We linked records from AIDS and cancer registries in 11 US regions (1990-1996). We studied 82,217 (86.6%) adults who had a CD4 count measured at AIDS onset and survived into the follow-up period. We calculated standardized incidence ratios (SIRs) for AIDS-defining (Kaposi sarcoma [KS], non-Hodgkin lymphoma [NHL] and cervical cancer) as well as non-AIDS-defining cancers in the 2 years after AIDS onset. For each cancer, the change in SIRs across CD4 counts (0-49 cells/mm3, 50-99 cells/mm3, 100-199 cells/mm3, and > or =200 cells/mm3) was modeled using Poisson regression.

Results: The SIRs for KS, NHL, and cervical cancer were 258, 78, and 8.8, respectively. For each fall of 100 CD4 cells/mm3, RRs were 1.36 (95% CI: 1.29-1.43) for KS and 1.48 (95% CI: 1.37-1.59) for NHL. Among NHL subtypes, the association with lower CD4 counts was strongest for immunoblastic lymphoma (RR =1.64, 95% CI: 1.37-1.96, per decline of 100 CD4 cells/mm3) and central nervous system lymphoma (RR = 2.29, 95% CI: 1.95-2.69). The SIR for cervical cancer did not vary with CD4 count (p =.74). For non-AIDS-defining cancers (overall SIR = 2.1), neither the combined risk nor the risk of specific types was associated with declining CD4 counts.

Conclusion: SKS and NHL risk increased with level of immunosuppression at AIDS onset. Risks for other cancers, including cervical cancer, were unrelated to CD4 counts. Elevated risks for non-AIDS cancers may be a result of lifestyle factors.