Physicians may need to dig deeper when treating HIV-related lymphomas

USC study finds differences in survival according to lymphoma type in post-HAART era

When it comes to treating HIV-positive patients with blood cancers, not all lymphomas are created equal, according to hematologists from the University of Southern California. Although physicians have treated all types of lymphomas in HIV/AIDS patients with the same drug regimens, researchers from the USC/Norris Comprehensive Cancer Center and Hospital say the drugs are significantly more effective in patients with diffuse large-cell lymphoma, or DLCL, than in patients with small non-cleaved, or SNC, lymphoma. The findings, reported at the 46th Annual Meeting of the American Society of Hematology, suggest that researchers rethink the practice of using the same uniform treatment for everyone with AIDS-related lymphomas.

“Lymphoma is not one disease, but rather represents a group of over 30 different entities. Even lymphomas that were thought to be quite uniform and homogeneous are now recognized as being made up of different variations or sub-types. It will be important for scientists and physicians to recognize these various types, since optimal therapy in the future will probably differ for these sub-types of disease,” says senior author Alexandra M. Levine, M.D., Distinguished Professor of Medicine, chief of hematology at the Keck School of Medicine of USC and medical director of the USC/Norris Cancer Hospital.

The USC hematologists reviewed records of more than 350 patients with the AIDS-related lymphomas treated at USC/Norris between 1982 and early 2004; 135 patients had SNC and 227 patients had DLCL.

The researchers looked at cases occurring before the advent of highly active antiretroviral therapy, or HAART, in 1996, as well as after the introduction of the successful anti-HIV therapy. They saw 117 SNC cases and 143 DLCL cases before HAART, and 18 SNC and 84 DLCL cases after HAART.

Throughout the period, all lymphoma patients were treated for their cancers with one of two equivalent, common chemotherapy combinations: cyclophosphamide, vincristine, adriamycin and prednisone; or methotrexate, bleomycin, adriamycin, cyclophosphamide, vincristine and dexamethasone.

USC/Norris researchers found that before HAART, overall survival of SNC and DLCL patients was about the same-about six or seven months. But after HAART, patients with DLCL began living significantly longer. DLCL patients’ average survival time after HAART’s 1996 introduction was 38 months-more than six times as long as SNC patients’ average survival time of 5.6 months.

The researchers also found that SNC patients were more likely than DLCL patients to have secondary cancer in their bone marrow, liver and kidneys. “Prior to the availability of effective treatment against HIV, patients with AIDS-related lymphoma often died of serious infections before they could receive adequate or optimal chemotherapy; the survival of these patients was quite short, in the range of only six months,” Levine says. “Importantly, effective anti-HIV treatment has now allowed these patients to receive chemotherapy, and to benefit from it.

“However, our study has shown that not all types of lymphoma are the same, and different treatments will be required to achieve optimal results in these individuals. We expect that our study will eventually serve to change the way in which patients with AIDS-related Burkitt lymphoma are treated.”