By Marilynn Larkin
NEW YORK (Reuters Health) – While the overall risk of secondary cancers after Kaposi sarcoma (KS) has declined in people with HIV/AIDS, clinicians should be aware that certain cancers are becoming increasingly common in the highly active antiretroviral therapy (HAART) era compared with the pre-HAART era, researchers say.
“Now that people with KS and HIV/AIDS are living longer, and the demographics of the patients with the disease have changed, the pattern of the tumors following KS (has) changed, according to our study,” Dr. Fahad Mukhtar, of the University of South Florida, told Reuters Health.
“For example,” he said by email, “in the past, tumors such as cervical cancer occurred significantly more than expected in patients with KS, but that’s not the case nowadays.”
Dr. Mukhtar and colleagues analyzed data in nine U.S. cancer registries on people diagnosed with KS from 1973 through 2013. Cancers secondary to KS were considered only if they were diagnosed at least two months after a KS diagnosis. Standardized incidence ratios (SIRs) were calculated for the development of new secondary cancers in the pre-AIDS era (1973-1979), pre–HAART era (1980-1995) and HAART era (1996-2013).
Among the 14,905 people diagnosed with KS during the study period, 92% were under age 65 at the time of diagnosis, 96% were men, and 81% were white. The team identified secondary cancers with incidences that were significantly higher than expected.
As reported online August 24 in JAMA Oncology, before 1980, only cancer of the ascending colon occurred at a higher-than-expected rate. From 1980 to 1995, the most common secondary cancers were cancer of the rectum, Hodgkin lymphoma, non-Hodgkin lymphoma, cancer of the liver, cancer of the cervix, and cancer of the anus.
From 1996 to 2013, cancer of the anus, Hodgkin lymphoma, non-Hodgkin lymphoma, and cancer of the liver remained associated with KS. However, significant associations were also seen for acute lymphocytic leukemia, cancer of the penis, and cancer of the tongue.
The incidence of secondary cancers overall decreased significantly from the pre-HAART era to the HAART era. After stratifying patients by age at diagnosis and cancer registries by region (higher vs. lower reported rates of HIV/AIDS), only non-Hodgkin lymphoma occurred significantly more than expected in people from regions with lower reported HIV/AIDS rates and among those who were age 65 or older.
All other secondary cancers were more common in people under age 65 and in regions with higher reported rates of HIV/AIDS.
“Physicians should be aware of these tumors and look out for them in patients with KS,” Dr. Mukhtar advised. “We were able to follow up these cases for a long time and noticed that some tumors developed after several years and, hence, long-term monitoring might be necessary.”
He stressed that the findings show association, not causality, between KS and the secondary tumors identified in the study. “Several factors could explain the co-occurrence of these cancers,” he said. “Genetics, immunity, and the viruses that are implicated in these cancers may be involved.”
“We also observed a higher number of cases of non-Hodgkin lymphoma in those with AIDS-related KS compared to classical KS,” he added. “Future research may focus on understanding the role that HIV/AIDS and Kaposi sarcoma play jointly in this association.”
Dr. Jeffrey Klausner, Professor of Medicine and Public Health at the UCLA David Geffen School of Medicine and Fielding School of Public Health, told Reuters Health, “The findings are not particularly surprising. With the advent of effective HIV treatment, we’d expect to see a decline in some cancers and perhaps a rise in other rarer forms.”
“The additional cancers like acute leukemia, penile and tongue cancer are rare and might reflect persons living longer or an aspect of the altered immune system in people with HIV,” he said by email. “Both penile and some oropharyngeal cancers are caused by human papilloma viruses, which can be prevented with vaccination.”
“(It) seems like more is needed to ensure everyone receives the HPV cancer vaccine,” Dr. Klausner concluded.
JAMA Oncol 2017.
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