Good survival for HIV patients diagnosed with non-Hodgkin's lymphoma

Two-thirds of HIV-positive individuals with non-Hodgkin’s lymphoma are alive a year after its diagnosis, European investigators report in a study published in the online edition of AIDS. A low nadir CD4 cell count was associated with poorer survival. Nevertheless, the investigators found that in the era of combination antiretroviral therapy, over 50% of HIV-positive patients diagnosed with a lymphoma were alive five years later.

“Our results thus support the notion that the gap in survival between non-Hodgkin’s lymphoma patients with and without HIV is closing”, comment the investigators.

Non-Hodgkin’s lymphoma is an AIDS-defining cancer and an important cause of death in patients with HIV. Since the introduction of effective HIV treatment, there has been a fall in the number of new cases of this cancer in people with HIV, and an improvement in the prognosis of patients in whom it is diagnosed.

Some earlier research has found that a number of HIV-related factors influence the prognosis of patients who develop lymphoma in the era of HIV treatment. These include a low CD4 cell count, a high viral load, and a history of previous AIDS-defining illnesses. Prognostic factors important in the course of the disease in HIV-negative patients, such as age, have also been shown to affect the outcome of HIV-positive patients.

In order to obtain a better understanding of prognosis of HIV-positive patients who develop non-Hodgkin’s lymphoma and the factors associated with this, researchers from the Collaboration of Observational HIV Epidemiological Research Europe (COHERE) study group conducted a study involving patients from 33 cohort studies.

A total of 67,659 patients were included in the investigators’ analysis and 847 of these individuals developed non-Hodgkin’s lymphoma. All were diagnosed with the cancer after January 1998, and none had experience of HIV treatment before that date. Of these patients, 10% were diagnosed with a primary lymphoma of the brain and 10% with Burkitt’s lymphoma.

The investigators divided the patients into three groups according to their experience of HIV treatment at the time this cancer was diagnosed: no HIV treatment; HIV treatment for under 90 days; HIV treatment for over 90 days.

Overall, the patients had a median age of 41 years and 82% were men. Non-Hodgkin’s lymphoma was diagnosed in 43% of patients before they started HIV treatment. Of the patients diagnosed with the cancer when taking HIV therapy, 14% had been taking this treatment for less than 90 days.

Median CD4 cell count at the time non-Hodgkin’s lymphoma was diagnosed was low at only 114 cells/mm³. This was accompanied by a high viral load (median, 181,000 copies/ml). Viral load was, however, lower in patients who were taking HIV treatment (less than 90 days, 126,000 copies/ml; over 90 days, 121 copies/ml).

Of the 763 patients with systemic non-Hodgkin’s lymphoma, 283 (37%) died. The proportion surviving one year was 66%, with 54% alive five years after their cancer was diagnosed.

A total of 38 of the 84 patients (45%) diagnosed with primary lymphoma of the brain died. The proportion surviving one year was 54%; however, data were too scarce to estimate five-year survival.

Statistical analysis showed that a lowest ever CD4 cell count below 25 cell/mm³ was significantly associated with a poorer prognosis (adjusted hazard ratio [AHR] = 1.64; 95% CI, 1.18 to 2.29). Older age at the time of diagnosis was also associated with poorer survival, as was injection drug use (AHR = 1.55; 95% CI, 1.08 to 2.21).

Diagnosis with primary lymphoma of the brain was also associated with poorer survival (AHR = 1.50; 95% CI, 1.01 to 2.23).

The investigators also found patients who had been taking HIV treatment for over 90 days at the time their lymphoma was diagnosed had a poorer outcome (AHR = 2.02; 95% CI, 1.56 to 2.61). The authors suggest that lymphomas that develop after HIV therapy has been started are likely to be more aggressive. For example, patients who develop the aggressive Burkitt’s lymphoma often have a CD4 cell count in the region of 200 cells/mm³.

“In the era of combination antiretroviral therapy two-thirds of patients diagnosed with HIV-associated systemic non-Hodgkin’s lymphoma survive for longer than 1 year after diagnosis,” conclude the investigators adding, “more advanced immunodeficiency is the dominant risk factor for death in patients with HIV-associated non-Hodgkin’s lymphoma.”