CD4 Level Predicts Cancer Risk in HIV

By Charles Bankhead, Staff Writer, MedPage Today
Published: October 07, 2009
Reviewed by Zalman S. Agus, MD; Emeritus Professor
University of Pennsylvania School of Medicine and
Dorothy Caputo, MA, RN, BC-ADM, CDE, Nurse Planner 

A falling CD4 count predicted increased susceptibility to seven types of cancer in people infected with human immunodeficiency virus (HIV), according to a study of more than 50,000 patients.

The cancers include both AIDS-defining and non-AIDS-defining malignancies, investigators reported online in The Lancet Oncology. They speculated that early diagnosis and treatment of HIV could delay the onset of at least some of the cancers.

The authors also recommended cancer-specific screening for HIV-infected individuals.

"Our results suggest that combination antiretroviral therapy would be most beneficial if it restores or maintains the CD4 count above 500 cells per microliter, thereby indicating an earlier diagnosis of HIV infection and an earlier treatment initiation," Marguerite Guiget, PhD, of the University of Pierre and Marie Curie and the French national health institute (INSERM), and colleagues concluded.

"Access to cervical-cancer screening programs should be regularly offered to all HIV-positive women, and cancer-specific screening programs, such as for lung cancer and for anal cancer, need to be assessed in HIV-infected patients," they wrote.

Improved treatment for HIV and AIDS has led to longer patient survival. However, that increased life expectancy has also brought an increased susceptibility to cancer.

Antiretroviral therapy's effect on cancer risk had not been carefully studied, the authors said.

So they studied it using records from the national French hospital database. They analyzed cancer risk in 52,278 HIV-infected patients from 1998 to 2006. The analysis included three AIDS defining cancers (Kaposi's sarcoma, non-Hodgkin's lymphoma, and cervical cancer) and four non-AIDS-defining cancers (Hodgkin's lymphoma, lung cancer, liver cancer, and anal cancer).

For each type of cancer, the authors evaluated 78 models derived from immunodeficiency status (defined by current CD4 count), viral load, and combination antiretroviral therapy.

Immunodeficiency predicted increased risk for all of the cancers, and CD4 count was the most predictive factor for all except anal cancer.

In general, cancer risk correlated inversely with CD4 count. For Kaposi's sarcoma, for example, a CD4 count of 350 to 499 cells/µL almost doubled the risk of a CD4 count of 500 or greater (RR 1.9, 95% CI 1.3 to 2.7).

If the patient had a CD4 count <50 cells/µL, the risk for Kaposi's sarcoma was 25 times greater than it was for patients with CD4 levels of 500 or greater (RR 25.2, 95% CI 17.1 to 37.0, P<0.0001).

Similar associations between CD4 count and cancer risk were observed for non-Hodgkin's lymphoma, Hodgkin's lymphoma, liver cancer, and lung cancer (P<0.0001 for each). A higher CD4 count lowered the risk of cervical cancer (RR 0.7 per log₂, 95% CI 0.6 to 0.8, P=0.0002).

HIV RNA load exceeding 100,000 copies/mL tripled the risk of Kaposi's sarcoma (RR 3.1, P<0.0001) and non-Hodgkin lymphoma (RR 2.9, P<0.0001).

Combination antiretroviral therapy predicted a lower risk of Kaposi's sarcoma (RR 0.3, P<0.0001) and cervical cancer (RR 0.5, P=0.03) and a trend toward a lower risk of non-Hodgkin lymphoma (RR 0.8, P=0.07).

The risk of anal cancer increased with duration of time with a CD4 count <200 cells/µL (1.3 per year, P=0.0001) and with a viral load >100,000 copies/mL (1.2 per year, P=0.005).