Antiretroviral therapy has extended the lives of people with HIV, but living longer may increase these patients' risk for certain cancers.
A study of nearly 90,000 HIV patients revealed a rise in three types of cancer as the AIDS-causing virus has evolved from a probable death sentence into a manageable chronic condition.
A significantly higher cancer risk
"We found that the risk of some cancers, such as anal, colorectal and liver cancers, is increasing over time mainly because HIV patients are living longer," said study lead author Michael Silverberg, of the Kaiser Permanente division of research in Oakland, California. Kaiser Permanente is one of the nation's largest health plans.
According to the U.S. National Cancer Institute, HIV patients have always faced a significantly higher cancer risk, most notably for Kaposi sarcoma, non-Hodgkin lymphoma and cervical cancer. That's because of a generally weakened immune system and a higher rate of infection with cancer-related viruses.
HIV antiretroviral therapy, launched in 1996, has curbed some of that elevated risk. Now, the study team explained, HIV patients receiving antiretroviral treatment can look forward to a lifespan of roughly 75 years.
However, cancer risk has not been brought down to general population levels. And some cancer risk has actually risen since the advent of antiretroviral therapy, the researchers said.
Results of the study are published in the 6 October issue of Annals of Internal Medicine.
The researchers focused on roughly 87,000 HIV patients and almost 197,000 non-HIV adults who participated in the North American AIDS Cohort Collaboration on Research and Design study between 1996 and 2009.
Investigators tracked the rate of nine types of cancer, including Kaposi sarcoma, non-Hodgkin lymphoma, Hodgkin lymphoma, lung cancer, anal cancer, colon/rectal cancer, liver cancer, oral cavity/pharyngeal cancer and melanoma. They also tallied each group's total cancer risk until age 75.
Improvements in care
The team determined that compared with non-HIV participants, cancer rates for HIV patients were higher across all nine cancers in every year examined.
However, declines were seen in the rate of Kaposi sarcoma – by 6 percent a year – and non-Hodgkin lymphoma, which fell by 8 percent a year, the study authors reported.
No change was noted for lung cancer, Hodgkin lymphoma and melanoma, the researchers said.
"This is because the increased risk of developing certain cancers that comes with living longer has been compensated by improvements in care, such as reduced smoking, increased awareness of the harmful effects of sun exposure, and improved immune function," said Silverberg.
But anal cancer and liver cancer incidence each went up by 6 percent a year, while colon cancer rose by 5 percent annually, the study found.
Why? A declining early death rate among HIV patients – about 9 percent a year – which provides greater opportunity for other diagnoses, the researchers said.
By contrast, no notable increase in cancer risk of any kind was observed among the non-HIV group.
"Knowing what the cancer risks actually are for today's HIV patients as they live longer is useful clinically, because it can help us prioritise which cancers we need to focus on for this group in terms of prevention," Silverberg said.
HIV now a long-term chronic condition
Cancer is only one aspect of a changing risk profile confronting today's HIV patients, said Dr Jeffrey Laurence, senior scientific consultant for programs at amfAR, the Foundation for AIDS Research.
"It's also heart disease, accelerated cardiovascular disease, osteoporosis and kidney disease, all of which are now more common among HIV patients," Laurence said.
Most likely, a longer lifespan is contributing to the increase in cancer and these other chronic conditions, he said. "In general, we need to be more aware of each patient's particular health profile, so we can perhaps modify or change treatment as needed to deal with the risks at hand," he said.
Study co-author Dr Michael Horberg, immediate past chair of the HIV Medicine Association, agreed.
As HIV has become a long-term chronic condition, "all sorts of health issues that patients and their doctors didn't think they had to worry about are now something they have to worry about," said Horberg, who is Kaiser Permanente's director of HIV/AIDS.
"It's no longer enough just to survive," he added. "You want to survive well."