According to researchers, the disparity in cancer mortality rates between older patients with both human immunodeficiency virus (HIV) and cancer and older patients who have cancer but not HIV is due to more than the suboptimal cancer treatment given to those with HIV.
It has previously been established that patients with both HIV and cancer have higher rates of cancer-specific mortality in comparison to other patients with cancer, yet the cause of this discrepancy has not been fully explained.
"To our knowledge, studies describing this association have not adjusted in detail for cancer treatment, despite evidence of suboptimal cancer treatment in the setting of HIV," comment the researchers in their publication in JAMA Oncology, led by first author Anna E. Coghill, PhD, MPH, Assistant Member of the Moffitt Cancer Center in Tampa, Florida. As a result, the investigators sought to answer the question, "Can the elevated mortality rate in HIV-infected patients with cancer [versus] HIV-uninfected patients with cancer be explained by receipt of suboptimal cancer treatment?"
The researchers analyzed data from the Surveillance, Epidemiology, and End Results (SEER)–Medicare linked database on 308,268 patients aged 65 and older diagnosed with early-stage colorectal, lung, prostate, or breast cancer between 1996 and 2012. Of these, 288 patients were infected with HIV. All patients included in the study had received standard, stage-appropriate treatment for their cancer during the year following their cancer diagnosis.
The patients who were infected with HIV had higher overall mortality rates than HIV-uninfected patients for colorectal cancer (hazard ratio of 1.73), prostate cancer (hazard ratio of 1.58), and breast cancer (hazard ratio of 1.50), along with increased cancer-specific mortality rates for prostate and breast cancer, with hazard ratios of 1.65 and 1.85, respectively. In addition, both HIV-infected men with prostate cancer and HIV-infected women with breast cancer experienced higher rates of relapse or death than their non–HIV-infected counterparts, with respective hazard ratios of 1.32 and 1.63.
"In the United States, elderly HIV-infected patients with cancer, particularly prostate and breast cancers, have worse outcomes than HIV-uninfected patients with cancer," conclude the study authors. The discrepancy, which the researchers note is present even after adjustment for administered first-course cancer treatments and may potentially result from an association between immunosuppression and cancer control, "will become increasingly relevant as the HIV population in the United States continues to age."
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Image credit: Seth Pincus, Elizabeth Fischer, and Austin Athman. Courtesy of the National Institute of Allergy and Infectious Diseases at the National Institutes of Health