Oct. 7 (HealthDay News) -- The weakened immune systems of people with HIV puts them at increased risk for at least seven types of cancer, but early diagnosis and treatment of HIV infection could help delay the onset of some of these cancers, a new study suggests.

French researchers examined the incidence of 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) in 52,278 HIV-infected people.

The study authors also analyzed the association between immunodeficiency, viral load, antiretroviral treatment and the onset of the seven cancers. Overall, immunodeficiency increased the risk of all the cancers, and CD4 cell count was the most predictive risk factor for all the cancers except anal cancer. The cancer risk associated with viral load was lower than that associated with immunodeficiency, the researchers noted.

CD4 count was the only risk factor for Hodgkin's lymphoma, lung cancer and liver cancer, the study found. Increased risk of Kaposi's sarcoma and non-Hodgkin's lymphoma was associated with lower CD4 count, higher HIV viral load and a lack of combination antiretroviral therapy (cART).

A higher CD4 count was associated with a lower risk of cervical cancer, and patients taking cART were half as likely to develop cervical cancer. Anal cancer risk increased with the time during which CD4 count was less than 200 cells per microliter and viral load was greater than 100,000 copies per milliliter, according to the report.

The study appears online Oct. 7 in advance of publication in the November print issue of The Lancet Oncology.

"Our results suggest that cART 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 earlier treatment initiation," the researchers wrote.

The study authors called for effective cancer-specific screening programs for HIV patients and said all HIV-positive women should be regularly offered cervical cancer screening.

SOURCE: The Lancet Oncology, news release, Oct. 7, 2009