Since the advent of effective combination antiretroviral (ARV) treatment two decades ago, the risk of many cancers has fallen for people living with HIV. However, this population’s risk for a slew of cancers remains elevated compared with the general population.
Publishing their findings in The Lancet HIV, researchers studied 1996 to 2012 data from the HIV/AIDS Cancer Match Study on 448,258 people with HIV, identifying cancer diagnoses among them through various corresponding cancer registries. Then they calculated what is known as a standardized incidence ratio to measure their risk of a cancer diagnosis compared with the expected cancer rate in the general population based on their sex, age, race, the year and the registry that provided the related data.
All told, the data set provided 3 million cumulative years of follow-up among the cohort of people with HIV. During that time, they received 21,294 cancer diagnoses.
Compared with the general population, the HIV-positive group had a 1.69-fold increased risk of cancer overall.
People with HIV had a 14-fold increased risk of AIDS-defining cancers, including the following cancers, which were associated with the corresponding increased risk of such cancers compared with the general population: Kaposi’s sarcoma, 498-fold; central nervous system non–Hodgkin lymphoma, 153-fold; unspecified non–Hodgkin lymphoma, 12-fold; diffuse large B cell lymphoma, 10-fold; and cervical cancer, 3.2-fold.
The risk of non-AIDS-defining cancers was 1.2-fold higher for people with HIV compared with the general population, including these virus-related cancers and their corresponding factors of increased risk: human papillomavirus (HPV)-related oral or throat cancers, 1.64-fold; anal cancer, 19-fold; liver cancer, 3.2-fold; and Hodgkin lymphoma, 7.7-fold. Additionally, the people with HIV had the following differing risks of various non-virus-related cancers, including both increased and decreased risk, compared with the general population: colon cancer, 39 percent decreased risk; rectal cancer, 31 percent reduced risk; prostate cancer, 52 percent reduced risk; and non-AIDS-defining non–Hodgkin lymphomas, 1.32-fold increased risk.
Looking just at the HIV population, the researchers compared the risk of cancer among those with AIDS with those without such a diagnosis, adjusting the data to account for differences based on sex or HIV risk group, age, race, year, cancer registry and follow-up duration. The investigators found that AIDS was associated with a 1.83-fold increased risk of all cancers, including a 3.15-fold increase of AIDS-defining cancers and a 1.45-fold increased risk of non-AIDS-defining cancers.
After adjusting the data for various factors, the study authors found that the relative risk for cancer among people with HIV, compared with the general population, narrowed between 1996 and 2012 for Kaposi’s sarcoma, two subtypes of non–Hodgkin lymphoma and cancer of the anus, liver and lung. However, all the rates remained elevated among people with HIV even at the end of the study period. There was no apparent increase in risk for any cancer over time.