Prostate and lung cancer will become the most frequently diagnosed cancers in people living with HIV in the United States by 2030 if current trends in new cancer diagnoses continue, an analysis by the US National Cancer Institute shows.
New cancer diagnoses are expected to fall by around 17% in people living with HIV by 2030, due to an 80% decline in the number of AIDS-defining cancers as a consequence of earlier diagnosis and treatment of HIV infection over the past two decades.
The projected changes in cancer diagnoses are a consequence of the ageing of people living with HIV and the success of antiretroviral therapy in preventing immunosuppression that leaves people vulnerable to AIDS-defining cancers such as Kaposi’s sarcoma and non-Hodgkin lymphoma.
The findings, published in Annals of Internal Medicine, highlight the importance of early detection and treatment of non-HIV-related cancers in people living with HIV, the investigators comment.
The analysis looked at the incidence of cancers that occur frequently in people living with HIV and those which occur most frequently in the general population, using data from the HIV/AIDS Cancer Match Study which links records of cancer diagnoses and HIV diagnoses.
The study looked at trends in cancer incidence between 2000 and 2012 by year, age group and HIV exposure category. Using an existing model of the HIV epidemic in the US population (HOPE), the researchers projected the incidence of cancers up to 2030 based on the observed trends and projected changes in the age structure of people living with HIV between 2010 and 2030.
They also calculated the total number of cancers expected to occur by 2030.
Between 2000 and 2012 the incidence of AIDS-defining cancers (Kaposi’s sarcoma, non-Hodgkin lymphoma, and cervical cancer) declined significantly (< 0.05), as did the incidence of anal cancer, lung cancer and Hodgkin lymphoma in all age groups. Colon cancer diagnoses declined in over-65s. Some previous studies have found that men living with HIV were at lower risk of developing prostate cancer, but the incidence of prostate cancer in men with HIV aged 35 to 64 increased significantly between 2000 and 2012 and now matches the rate seen in the general population for this age range.
Rates of breast cancer declined slightly in all age groups of women living with HIV.
Based on these trends the researchers estimated that prostate cancer will increase among men aged 35-64, becoming the most common cancer among all people with HIV in the US by 2020 (1340 projected cases). By 2030, prostate cancer will occur more frequently (1590 cases a year) than lung cancer and anal cancer combined, the next most frequently occurring cancers (1030 cases and 450 cases respectively), and will account for at least one in five of all cancers diagnosed in people living with HIV.
The projected increase in prostate cancer cases in men is attributable to the change in the age structure of the population of people living with HIV rather than an increase in the risk of prostate cancer for all men with HIV. Whereas 8.5% of the US population of people living with HIV was 65 or older in 2010, 21.4% will be over 65 in 2030 (an increase from 96,000 to 234,000), the model projects. Similarly, the proportion of the population aged 45-64 will grow from 39.4% in 2010 to 47.7% in 2030 (an increase from 444,000 to 520,000). The incidence rates of all other cancers will either stabilise or decline. Substantial reductions in the incidence of the AIDS-defining cancers Kaposi’s sarcoma, non-Hodgkin lymphoma and cervical cancer up to 2010 will continue. The incidence of colon cancer will continue to decline in people aged 65 and over.
Approximately five in every thousand people living with HIV aged 65 and over will develop prostate cancer in 2030, the model projects, compared to three in every thousand aged 65 and over who will develop lung cancer. A similar proportion will develop liver cancer. No other cancers will occur at rates above one in a thousand in 2030.
The investigators say that the accuracy of their estimates of lung cancer burden “may not be realistic if the prevalence of smoking does not decrease substantially among PLWH [people living with HIV].”