BRUSSELS — It is likely that the incidence of infection-related malignancies will decline as people infected with HIV live longer because of antiretroviral therapy, but the incidence of malignancies unrelated to infection will gradually increase, new research shows.
Age is much more strongly associated with malignancies unrelated to infection than with those related to infection, said biostatistician Leah Shepherd, from the University College London in the United Kingdom. "As the population continues to age, we're going to see an increasing proportion of malignancies unrelated to infection."
Shepherd reported data from EuroSIDA, a large prospective cohort study, to a packed auditorium here at the 14th European AIDS Conference.
EuroSIDA collects laboratory and treatment data on clinical AIDS and non-AIDS events, deaths, causes of death, and smoking from HIV-infected patients at 108 clinics in Argentina, Europe, and Israel.
Shepherd and her team correlated age with cancer incidence, and estimated the future burdens of malignancy in people with HIV.
Since January 2001, EuroSIDA has accumulated data on 15,648 people with 95,033 person-years of follow-up. During a median follow-up of 6 years, 610 people developed 643 malignancies. Of these, 388 (60.3%) were related to infection and 255 (39.7%) were not.
Infection-related malignancies are cancers with a clear infectious cause. Hodgkin's and non-Hodgkin's lymphoma are related to Epstein–Barr virus; Kaposi's sarcoma is related to human herpesvirus 8; liver cancer is related to hepatitis B or C virus; stomach cancer is related to Helicobacter pylori; and cancers of the base of the tongue, pharynx, tonsils, anus, vagina, vulva, and penis, as well as invasive cervical cancer, are related to human papillomavirus.
The most common malignancies in the EuroSIDA cohort were non-Hodgkin's lymphoma (18%), anal cancer (13%), Kaposi's sarcoma (10%), and lung cancer (9%).
During the study period, there was a significant decline of 4.9% annually in the incidence of infection-related malignancies. However, after adjustment for age, calendar year, region, sex, previous AIDS or AIDS-defining malignancy, ethnicity, smoking status, clinical confounders, and laboratory confounders, the difference was not significant (annual adjusted incidence ratio, 1.02; 95% confidence interval [CI], 0.98 - 1.06).
The incidence of malignancies unrelated to infection was stable over time and after adjustment.
However, assuming that a 10-year increase in age is a predictor and that current trends continue, it is expected that malignancies unrelated to infection will slowly increase in the future and that infection-related malignancies will decrease.
Table. Forecasted Trends in Unadjusted Incidence of Malignancy*
| Malignancy | 5-Year Incidence (95% CI) | 10-Year Incidence (95% CI) |
| Related to infection | 2.27 (1.13–4.08) | 1.72 (0.86–3.11) |
| Unrelated to infection | 3.58 (1.38–7.65) | 4.07 (1.56–8.72) |
| *Per 1000 person-years of follow-up |
||
Shepherd emphasized that although both types of malignancies are associated with older age, independent of many known risk factors, age is much more strongly associated with malignancies unrelated to infection.
"As the HIV-infected population continues to age, we're going to see an increasing proportion of malignancies unrelated to infection. Therefore, targeted preventive measures and studies evaluating the cost-benefit of screening should be considered," she advised.
Shepherd pointed out that limitations of this study are its observational nature, small counts, lack of population projections, and the fact that follow-up only starts in 2001.
"I would have liked to have seen the exact rates for the normal population, but we don't have standard incidence rates, as they do in the United States or across Europe," said session chair Fiona Mulcahy, MD, from St. James's Hospital of Trinity College in Dublin, Ireland. "I'm not sure how significant these findings will be going forward as patients age," she told Medscape Medical News.
However, she added, it is encouraging that projections show "virally related tumors going down. I think it does make you think that if you have an aging population, they will get other tumors. Maybe we're biased, in that we are now seeing a lot of cancers coming through with our aging population. It might just be that we have moved, as physicians, from looking after a younger group to an older group, and we're not used to seeing them in their entirety," Dr. Mulcahy explained.
She suggested that future studies of this nature include an HIV-negative control population to see if HIV-infected patients are developing cancers at a similar or different rate.
This study was supported by grants from the European Commission and the Swiss National Science Foundation, and unrestricted grants from BMS, Janssen, Merck, Pfizer, and GSK. Ms. Shepherd has disclosed no relevant financial relationships. Dr. Mulcahy reports financial relationships with AbbVie, BMS, Merck, GSK, and Gilead.
14th European AIDS Conference: Abstract PS6/5. Presented October 17, 2013.
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Cite this: Malignancies Expected to Rise in People With HIV - Medscape - Nov 05, 2013.
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