For people living with HIV, a cancer diagnosis must seem like a cruel twist of fate. Unfortunately, as a new study published Tuesday in the journal Cancer reveals, it’s one that’s often substantially worse than it would be for most anyone else.

The researchers analyzed the National Cancer Data Base, specifically looking at adults under the age of 65 who were diagnosed with some of the most common cancers from 2003 to 2011. From there, they compared the outcomes of 10,265 cancer cases in HIV-infected patients to the remaining 2.2 million cases in people without HIV. Nearly across the board, people living with both conditions were less likely to ever obtain cancer treatment than their uninfected counterparts. While this gap could be partly explained by the greater lack of private insurance among HIV-positive patients, it still remained after accounting for that and other factors.

“In the United States, HIV-infected patients with cancer appear to be less likely to receive cancer treatment regardless of insurance and comorbidities,” the authors concluded, adding that theirs is likely the largest such study of cancer treatment in HIV-infected patients.

Breaking it down by cancer type, people living with HIV were more than twice as likely to not obtain treatment for lung, prostate, and breast cancers, among others. And they were nearly twice as likely to not get care for Hodgkin's lymphoma, colorectal cancer, and cancers of the head and neck. Only anal cancer saw similar treatment rates across both groups.

Besides insurance status, race and tumor type tended to be the strongest predictors of whether someone living with HIV would get treated, People who were black or had solid tumors, such as those found in breast cancers, were less likely to get care.

While these sorts of studies can’t definitively tell us why a difference exists, the researchers had some educated guesses. Clinical trials for new cancer treatments often exclude people who have other chronic conditions such as HIV, and there are few cancer treatment guidelines that specifically address HIV-infected patients. Both of these might serve to make cancer treatments, particularly newer ones, less accessible to these patients and their doctors. In that same spirit, oncologists might also have less experience specifically treating that population. Lastly, for some people living with HIV, the added financial, physical, and mental burden of taking on yet another chronic condition may be too much for them to handle.

Unfortunately, as people living with HIV have gotten older, so has their risk of developing other age-related health problems, including cancer. Most recently, a 2015 study of 1,115 HIV-infected patients in Taiwan found they were at a higher risk for cancers of the kidney, mouth, and breast, among many others. And earlier research has found the same link in other countries as well.

Finding ways to better understand and repair the treatment gap will undoubtedly require extra attention on the part of medical providers and policy makers, the authors wrote, but it’s an effort that would be well worth the resources.

“Cancer treatment not only extends survival from cancer, but also can improve quality of life, even for patients with advanced-stage disease,” they wrote. “The observed disparity is of particular importance given the extended survival of HIV-infected patients treated with antiretroviral therapy and the rising number of cancer cases.”

Source: Suneja G, Lin C, Simard E, et al. Disparities In Cancer Treatment Among Patients Infected With The Human Immunodeficiency Virus. Cancer. 2016.