Non Hodgkins lymphoma

The second most common malignancy to affect those with AIDS. Almost half of these will already have a prior AIDS-defining illness. Unlike KS, its incidence is 3% within all risk groups—one hundred times higher than in the general population. NHL also has a higher incidence in other congenitally and iatrogenically immune-suppressed individuals.

A viral co-factor—the Epstein-Barr virus (EBV)—is closely linked to the development of lymphoma in AIDS. EBV proteins can be demonstrated in 50% of lymphomas in nodal or extra-nodal sites. It is thought that in the immune-deficient host the proliferation of EBV-infected cells may proceed unchecked. Oncogenic alterations, e.g. p53 and C-myc, have also been identified. 90% of HIV-related NHLS are of B-cell origin and are commonly high-grade. The most common subtypes are immunoblastic, centroblastic, lymphoblastic, and Burkitt-like lymphoma.

Presentation

♦ At advanced stage

♦ Usually involves marrow and CNS (extra-nodal)

♦ Frequently B symptoms

♦ Differential diagnosis TB, CMV

♦ Gland biopsy essential

♦ Investigations—chest X-ray, CT head, abdomen, pelvis

—bone marrow biopsy —LDH level —lumbar puncture

♦ Poor prognosis—median survival 6 months

—50% die from opportunistic infections —50% die from lymphoma

Prognosis

Poor prognostic factors include:

♦ Prior AIDS-defining diagnosis

♦ Karnofsky performance score <70

♦ Extra-nodal disease including bone marrow

♦ Immunoblastic subtype

Treatment

Systemic treatment with chemotherapy is usually the only available curative treatment. However, if the disease is truly localized, radiotherapy can result in long-term control and is invaluable for the palliation of local symptoms.

The standard treatment for more advanced disease is combination chemotherapy. CHOP (cyclophosphamide, doxorubicin, vincristine, prednisolone) is a typical chemotherapy regimen, given every three weeks. More intensive schedules can be used, but due to increased toxicity are often not well tolerated. In those at high risk of meningeal involvement, concomitant intrathecal chemotherapy of methotrexate and cytarabine is also used.

Recent studies suggest that more aggressive chemotherapy regimens result in an overall decrease in survival due to toxicity-related complications. Modified schedules including a 75% dose reduction may produce similar response and overall survival rates. Those who achieve a complete response with chemotherapy have a survival benefit ranging from 6-20 months.

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