Long-Term Antiretroviral Therapy Fails to Reduce Anogenital Cancer Risk
Long-term antiretroviral therapy does not reduce the elevated risk of anogenital cancer among people with HIV, according to study findings published in Clinical Infectious Diseases. Researchers evaluated adults with and without HIV to determine whether prolonged treatment decreases the incidence of cervical, vulvar, anal, and penile malignancies, many of which link directly to human papillomavirus infection. While antiretroviral drugs successfully restore immune function and suppress viral loads, the relative risk for these specific cancers actually climbs among patients receiving treatment for a decade or longer, as Infectious Disease Advisor reported.
Evaluating Treatment Duration in Botswana
Investigators conducted a prospective case-cohort study emulating a target trial in Botswana using data collected between 2013 and 2018. The research combined information from the Thabatse Cancer Cohort, which enrolled patients with incident anogenital cancers at four major oncology centers, and the Ya Tsie HIV prevention trial, which supplied a population-based sample from 30 communities. The analysis tracked 14,312 adults aged 30 to 65 years, where 42 percent of participants had HIV. Cervical cancer accounted for most diagnoses with 792 cases, followed by 106 vulvar cases, 80 anal cases, and 67 penile cancers.
Comparative Risk Across Treatment Windows
Scientists classified participants into five distinct groups based on HIV status and antiretroviral exposure: individuals without HIV, patients not receiving treatment, and patients receiving therapy for under five years, five to nine years, or ten years and longer. Weighted regression models estimated relative risks while adjusting for demographic characteristics, human papillomavirus exposure factors, access to cancer care, and a history of advanced HIV disease. Patients receiving treatment for at least a decade exhibited an estimated relative risk of 7.4 compared to people without HIV. By comparison, the estimated relative risk stood at 4.6 for untreated patients, 4.0 for those treated under five years, and 4.6 for those treated between five and nine years, with the overall trend reaching statistical significance at $P = .001$.
Cancer-Specific Findings After Ten Years
Disparities emerged across individual cancer types among patients receiving treatment for ten years or more when compared against uninfected control participants. Penile cancer showed a relative risk of 102, vulvar cancer reached 35.7, anal cancer registered 14.9, and cervical cancer stood at 4.4. Within an analysis restricted solely to people with HIV, patients on treatment for a decade or longer faced higher estimated risks than those treated for less than five years. Those relative risk figures reached 1.3 for cervical cancer, 5.6 for vulvar cancer, 10.0 for anal cancer, and 6.9 for penile cancer, with significant upward trends across duration categories for all four malignancies.
What Are the Study Viral Suppression and Age Rates?
What proportion of participants had achieved viral suppression during the study?
Among participants receiving antiretroviral therapy who had available viral load measurements, 98 percent maintained HIV RNA levels below 1000 copies per milliliter.
How did age and disease history differ between treatment duration groups?
Participants receiving treatment for at least ten years showed a median age of 46 years, compared to 43 years for those treated for less than five years. A history of advanced HIV disease affected 100 percent of the decade-plus treatment group, compared to 26 percent of those in the shorter treatment bracket.
Which specific cancer diagnosis accounted for the majority of cases in the cohort?
Cervical cancer represented the vast majority of the 1,045 total incident anogenital cancer diagnoses recorded in the study, accounting for 792 individual cases.
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