June 13, 2013
Researchers investigated the incidence and timing of cancer diagnoses among patients who began triple-drug antiretroviral therapy (ART) between 1996 and 2011. The researchers reviewed the records of approximately 11,500 persons, examined trends in cancer incidence for up to 10 years after treatment initiation, and investigated factors associated with a cancer diagnosis.
The researchers divided cancers into different categories: AIDS-defining cancers (Kaposi's sarcoma, non-Hodgkin's lymphoma, and cervical cancer); non-AIDS-defining cancers; lymphomas; cancers related to human papillomavirus (HPV); other virus-related cancers; and virus-unrelated cancers. Patients were mostly male (80 percent) and racially diverse. Median age at which they started ART was 38 years and most patients were immunosuppressed when they began treatment. The researchers followed patients for a median of three years and followed 10 percent of patients for 10 years.
Data showed 457 cancer diagnoses in 46,318 person-years of follow-up, which provided an incidence rate of 987 cases per 100,000 person-years.
Incidence of AIDS-defining cancers was similar to that for non-AIDS defining cancers (515 versus 466 per 100,000 person years). Kaposi's sarcoma was the most common AIDS-defining cancer. The most common non-AIDS cancer among women was breast cancer and among men was anal cancer. Timing of cancer diagnosis differed based on whether or not the cancer was AIDS-defining. Incidence of Kaposi's was very high in the first six months after therapy, fell during the second six months, and remained low during the follow-up. Lymphomas followed the same trend. Incidence of non-AIDS defining cancers increased with longer duration of follow-up, increasing 7 percent for each additional year of treatment. Each 10-year age increase doubled the risk of non-lymphoma cancers and HPV-related cancers. CD4 cell count at the time of therapy initiation was associated with cancer risk -- low CD4 cell count was associated with lymphomas and HPV-related cancers.
Results show that ART improvements did not affect the incidence of cancer in patients with HIV infection. The researchers contended that results emphasized the need for early HIV diagnosis, prevention measures such as vaccines, and cancer screening for persons with HIV.
The full report, "Incidence and Timing of Cancer in HIV-Infected Individuals Following Initiation of Combination Antiretroviral Therapy," was published online in the journal Clinical Infectious Diseases (2013; doi: 10.1093/cid/cit369).