Management of HIV-Associated Hodgkin Lymphoma: How Far We Have Come

Although Hodgkin lymphoma (HL) is not considered an AIDSdefining malignancy, population-based studies have demonstrated an increased incidence of this disease in the setting of HIV infection. In a prospective cohort study of 11,112 individuals who were positive for HIV, with 71,687 patient-years of follow-up, the incidence of HL was 14 times higher than in the general population. In contrast to other HIV-associated malignancies that occur more commonly with severe immunocompromise, HL is associated with moderate immunologic impairment and the incidence actually seems to decline at CD4 lymphocyte counts of less than 200/ L. Although incidence rates for the AIDS-defining malignancies (Kaposi’s sarcoma, aggressive B-cell non-Hodgkin lymphoma [NHL]) have fallen, the incidence of HL may actually be increasing since the advent of combination antiretroviral therapy (cART), perhaps as a consequence of improvement in the level of immune function. However, the increased relative risk of HL is substantially lower than that observed for aggressive B-cell lymphoma. As a result of the small number of cases, studies investigating approaches to management of HIV-associated HL have been largely retrospective in design. For the more common AIDS-defining lymphomas, diffuse large B-cell lymphoma and Burkitt lymphoma, outcomes have improved dramatically in the 16 years since the introduction of active antiretroviral therapies, which have transformed HIV disease into a survivable chronic illness. Prospective studies in the pre-cART era demonstrated 2-year overall survival (OS) in the 10% to 20% range with complete remission (CR) rates of 35% to 50%, far inferior to those observed in non-HIV–associated lymphomas. Prognosis at that time was largely dependent on the severity of immunosuppression rather than on features of the lymphoma. This experience changed with the advent of cART such that now treatment outcomes using standard regimens such as rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone or dose-adjusted etoposide, prednisone, vincristine, cyclophosphamide, doxorubicin, and rituximab approach those observed in the non-HIV–infected population, with CR rates of 65% to 77% and 2-year OS rates of more than 60%. The International Prognostic Index (IPI) score seems to be a significant prognostic factor in patients treated with chemotherapy and concurrent cART. On the basis of the age-adjusted IPI score, the survival of patients in one trial using rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone was similar to that achieved by patients with aggressive lymphomas who were not infected with HIV. HL in the HIV-seropositive population is more likely to have mixed cellularity or lymphocyte-depleted histology and is almost always Epstein-Barr virus–associated. The majority of patients present with advanced-stage disease. Before the introduction of cART, treatment outcomes for HIV-HL were poor. In an Italian retrospective study of 114 patients with HIV-associated HL who received various standard chemotherapeutic regimens, the median OS was 15 months. Sixty percent died, 35% of those from opportunistic infection, 33% from HL, and 12% from both. As has been the case for aggressive B-cell lymphomas in patients with HIV infection, small retrospective and prospective studies have suggested improvement in outcome with the advent of cART. A retrospective study of doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD) with cART in 62 patients with advanced-stage HIVassociated HL demonstrated a CR rate of 87% and 5-year OS of 76%. A prospective trial reported a CR rate of 81% and 2-year OS of 51% in 59 patients treated with the Stanford V regimen (doxorubicin, vinblastine, mechlorethamine, vincristine, bleomycin, etoposide, and prednisone) administered with antiretroviral therapy. The fact that only 10% of these patients received radiotherapy suggests that the regimen was either not delivered as designed or that the inclusion of patients with early-stage and low-bulk disease (factors associated with inferior outcome with this regimen) resulted in relatively disappointing outcomes. In the article that accompanies this editorial, the German HIV-Related Lymphoma Study Group presents data from the largest prospective trial ever conducted in patients with HIV-associated HL. In this study, 112 patients were allocated to treatment on the basis of stage and risk category. Those with early-stage favorable disease (IA/B or IIA/B) received two to four cycles of ABVD plus 30 Gy of involved-field radiotherapy. Patients with early-stage unfavorable disease received four cycles of bleomycin, etoposide, doxorubicin, cyclophosphamide, vincristine, procarbazine, and prednisone (BEACOPP) at baseline or four cycles of ABVD followed by 30 Gy of involved-field radiotherapy if disease was 5 cm or residual disease was 2 cm. Those with advanced disease received eight cycles of BEACOPP with or without radiotherapy to sites 2.5 cm. Patients with advanced HIV disease, including Eastern Cooperative Oncology Group performance score 2, received ABVD. There were five toxic deaths: 4% with early favorable, 0% with early unfavorable, and 7% with advanced disease. CR rates were 96%, 100%, and 86% for these three groups, respectively, and 2-year PFS JOURNAL OF CLINICAL ONCOLOGY E D I T O R I A L VOLUME 30 NUMBER 33 NOVEMBER 2