Objective: To evaluate, with the support of autopsy findings, the frequency of non-Hodgkin's lymphoma (NHL) among patients with AIDS-associated Kaposi's sarcoma (KS) in comparison with that of AIDS patients with other AIDS-defining diseases.
Methods: The study involved 363 consecutive patients with AIDS who were cared for and died at the Clinic of Infectious Diseases in Milan between May 1984 and December 1992. Clinical records and autopsy data of all of the patients were retrospectively reviewed. Kaplan-Meier product-limit estimates of the time to the development of NHL were calculated for all patients and by specific subgroups. Cox proportional hazards analyses were made to determine the factors associated with the development of NHL.
Results: In the majority of cases (82%), KS was diagnosed during life, whereas NHL was diagnosed before death in only 41.6% of cases. Taking the autopsy data into account, the cumulative incidence of the two tumours was 16.8% for KS and 16.5% for NHL. Among the 61 patients in whom KS was the index disease of AIDS, 16 also developed NHL. The probability of developing NHL was significantly higher in patients with KS at AIDS diagnosis than in patients with Pneumocystis carinii pneumonia (PCP), oesophageal candidiasis or other AIDS-related diseases (P = 0.004). Multivariate analysis of the factors associated with the development of NHL (such as sex, age, risk factors, AIDS-defining diseases and CD4+ cell counts) showed that the patients with KS as the index disease of AIDS had a 5.3-fold higher risk of developing NHL than the patients with PCP as the primary manifestation of AIDS.
Conclusions: Our results confirm the higher incidence of malignant lymphoma in patients with AIDS-KS than in patients with other AIDS-related diseases. The importance of autopsy in assessing these data is underlined by the high percentage of NHL diagnosed only after death. These observations may support the hypothesis of a common aetiological agent, or of a common pathway, for the two neoplasms.