HIV-infected people diagnosed with cancer are two to four times more likely to go untreated for their cancer compared to uninfected cancer patients, according to a new, large retrospective study from researchers in Penn Medicine's Abramson Cancer Center and the National Cancer Institute (NCI) published online ahead of print in the Journal of Clinical Oncology.

Life expectancy for HIV-infected people is now similar to uninfected people, but survival for HIV patients who develop cancer is not. While many studies have attempted to understand why HIV-infected cancer patients have worse outcomes, the new study, the largest of its size and scope, examined differences in cancer treatment as one potential explanation. For early-stage cancers that have the highest chance of cure with appropriate treatment, those with HIV were twice to four times as likely to not receive appropriate cancer treatment, the researchers found. HIV-infected people with lymphoma, lung cancer, prostate cancer, and colorectal cancer were almost twice as likely to be untreated for cancer, even after considering differences in age, gender, race, and stage.

"In my clinical experience, I have seen uncertainty surrounding treatment of HIV-infected cancer patients," said the study's lead author, Gita Suneja, MD, an adjunct assistant professor in the department of Radiation Oncology at the Perelman School of Medicine at the University of Pennsylvania and in the Abramson Cancer Center. "Patients with HIV have typically been excluded from clinical trials, and therefore oncologists do not know if the best available treatments are equally safe and effective in those with HIV. Many oncologists rely on guidelines based on such trials for treatment decision making, and in the absence of guidance, they may elect not to treat HIV-infected cancer patients due to concerns about adverse side effects or poor survival."

"This could help explain in part why many HIV-positive cancer patients are not receiving appropriate cancer care," she added.

Dr. Suneja collaborated with researchers at the NCI, as well as registrars from three states - Connecticut, Michigan, and Texas - that provided data to NCI's HIV/AIDS Cancer Match Study. The researchers used the data to study adults diagnosed with non-Hodgkin lymphoma, Hodgkin lymphoma, or cervical, lung, anal, prostate, colorectal, or breast cancer from 1996 through 2010. Over 3,000 HIV-infected and one million uninfected cancer cases were examined.

The advent of antiretroviral therapy has changed the outlook in the fight against HIV/AIDS. People with HIV are living longer and healthier lives, and a disease that was once thought to be universally fatal has now become a chronic and manageable disease like diabetes or hypertension.

In the early era of the HIV epidemic there were reports of worse toxicity and side effects, but there are now more effective ways to support the immune system, most of them safe, tolerable and effective. Still, treatments for cancer patients with HIV can be clinically challenging due to drug interactions and the potential increase in immunosuppression from chemotherapy or radiation.

To help close the disparity gap among HIV positive patients with cancer and those not infected, cancer clinical trials should begin enrolling HIV-infected patients, the authors suggest, and cancer management guidelines should incorporate recommendations for HIV-infected patients.

"The results of this study are very concerning and require further investigation to understand why such a substantial proportion of HIV-infected cancer patients are not undergoing life-saving treatment," said Dr. Suneja. "As cancer becomes an increasingly common cause of death in the HIV population, the issue of cancer treatment in the HIV-infected cancer population will grow in importance."