HIV-Associated Cancers: A Paradigm Shift?
Many HIV-associated cancers develop with the help of oncoviruses — some of which are sexually transmitted.
An increasing number of patients with HIV now live long enough to get the “incidental” cancers seen in the general population. Yet these patients are also less likely to get the 3 cancers that once defined AIDS — Kaposi sarcoma, aggressive B-cell lymphoma, and invasive cervical cancer — which were frequently seen when the disease was first observed.
Researchers attribute the significant decline in the burden of AIDS-related cancers to successful combination antiretroviral therapies that emerged in the mid-1990s. These therapies can keep HIV quiescent for years, enabling the immune system in some patients to fully or partially recover.
“It's a complex story,” said Robert Yarchoan, MD, chief of the HIV and AIDS malignancy branch at the National Cancer Institute (NCI) in Bethesda, Maryland, and co-author of a recent review of HIV-associated cancers in The New England Journal of Medicine.1 “With the dramatic drop in AIDS-defining cancers, a number of my colleagues thought cancer would be mostly going away as a problem in HIV patients.”
Instead, while the number of AIDS-defining cancers has held relatively steady in the United States for 2 decades, he said, the incidence of other cancers is rising, as HIV-infected individuals are living longer.
The proportion of HIV-infected individuals who develop cancer-related complications or die from cancer remains undetermined, with one French study suggesting it's now the leading cause of death in HIV patients.2 Yet many clinicians shy away from offering standard cancer therapies to these patients, Dr Yarchoan said, calling this an under-appreciated situation slowly gaining recognition in the medical community.3
Although early in the AIDS epidemic many patients were too fragile to withstand the rigors of chemotherapy, that's no longer the case today with improved antiretroviral therapies, he said, adding that “many HIV cancer patients can tolerate chemotherapy just as well as uninfected individuals.”
Richard Ambinder, MD, PhD, director of the division of hematologic malignancies at Johns Hopkins Hospital in Baltimore, Maryland, agreed. “Not treating HIV-infected patients who develop cancer with chemotherapy — that's a real problem,” he said. “HIV should be seen as a chronic disease, which, like diabetes, carries other health ailments that need to be addressed, but should not preclude cancer treatment.”
In February, the National Comprehensive Cancer Network (NCCN) took steps to remedy this “disparity in cancer care,” issuing the first treatment guidelines for people living with HIV who are later diagnosed with cancer.4
According to the most recent data, an estimated 7760 patients in 2010 had these overlapping medical conditions, yet were 2 to 3 times less likely to receive appropriate cancer care. The NCCN guidelines call for clinicians to treat these patients with the same cancer therapies as offered to HIV-negative individuals. They also call on physicians to work with oncologists and HIV specialists to manage potentially toxic interactions between cancer drugs and antiretroviral drugs before initiating therapy.
“Treating people living with HIV for cancer is a relatively new concern,” said Robert Carlson, MD, chief executive officer of NCCN, in a prepared statement.5 “It's both a testament to the successes of HIV treatments in recent years and a reminder that the quest for healthier outcomes is ongoing.”
Among the most common non-AIDS defining cancers in HIV-infected individuals are lung, liver, anal cancer, and Hodgkin lymphoma. Of these, lung cancers occur not only with increasing frequency compared with the general population, but also often present at a more advanced stage of disease .
This greater lung cancer risk in HIV patients is not understood. “We don't know whether HIV infection increases the risk of lung cancer or whether high rates of smoking or other exposures increases the risk, or both,” Dr Ambinder said.