Testing Cancer Patients for HIV: Just Do It
Authors: Salvaña, MD, DTM&H Edsel Maurice T. 
Published: March 2024

Who do we test for HIV? In a perfect world, the answer to this question is, “Everyone.” The United States Centers for Disease Control and Prevention (CDC) recommends that anyone between the age of 13 to 64 years old should have at least one HIV test as part of routine healthcare. 1 In addition, they recommend that anyone who comes into contact with the healthcare system be tested, along with all pregnant women. The main justification for these recommendations is that 40% of new HIV infections in the United States are transmitted by people who do not know their HIV status, which is about 10% of their people living with HIV (PLHIV). 2
In the Philippines, the testing gap is even wider. Out of an estimated 160,000 PLHIV in 2022, only 102,931 PLHIV were tested and diagnosed. This translates to nearly 40% of all Filipino PLHIV remaining undiagnosed and potentially infecting others. 3 The testing coverage for the most-at-risk populations in the Philippines remains dismal at 67% for female sex workers (FSW), 28% for men who have sex with men (MSM), and 27% for persons who inject drugs (PWID). Successfully addressing the HIV epidemic begins at diagnosis, and so improving testing is of paramount importance.
There are two major compelling public health reasons to test people for HIV. First is to start life-saving antiretroviral therapy (ART) as soon as possible. The sooner a PLHIV starts ART and stays on it, the more life years are recovered up to nearly restoring life expectancy. 4 The second reason is to eliminate the risk of transmission to other people. Starting ART and achieving a suppressed viral load renders a PLHIV virtually unable to transmit. 5
In this issue of the journal, Poblete and his colleagues6 try to make the case for universal HIV screening of Filipino cancer patients. While they did not find any HIV cases among the 124 patients they screened, they did note that risk factors among the study population were low. They still encouraged physicians to offer HIV screening to all cancer patients given the overwhelming benefits of treatment.
Targeted versus universal HIV screening has been a long ongoing academic debate and there are pros and cons supporting each approach. 7 A low overall prevalence like in the Philippines will be associated with higher costs per case detected with universal screening, but this could potentially be offset by the cost of missed cases in targeted screening. The CDC in past guidance has asserted that universal HIV screening in a specific risk population with an HIV prevalence of at least 0.1% is cost-effective. However, it eventually updated this guidance, urging universal screening regardless of risk factors or prevalence due to the clear benefits of early antiretroviral therapy both from an improved survival and decreased transmission standpoint. 1 In 2010, we did a study doing universal screening on cervical cancer patients and found no cases of HIV among 394 subjects at the Philippine General Hospital (PGH). 8 However, we do have several PLHIV with cervical cancer in the SAGIP clinic in PGH. The failure to capture these patients in the study could be due to several reasons, including an underpowered sample size, poor random sampling, or those with higher risk factors declined to participate due to stigma. In a parallel study, we found no HIV cases in 400 pregnant women. 9 Despite this finding, universal screening among pregnant women continues to be recommended and is needed to eliminate maternal to child transmission of HIV.
There are more aspects to consider in recommending an HIV test beyond cost-effectiveness, underlying prevalence, and risk factors. Many infectious diseases physicians, including myself, recommend universal HIV screening for all cancer patients, especially those who are going to undergo chemotherapy regardless of risk factors. Given the severe immunosuppression that results from chemotherapy, the presence of an undetected HIV diagnosis can result in catastrophic medical consequences. Furthermore, certain AIDS-defining illness such as Kaposi’s sarcoma and lymphomas respond to treatment much better once antiretrovirals have been started.
Studies like Poblete et al. 6 are ultimately useful for periodic surveillance to check whether the prevalence of HIV in special populations is increasing, but negative findings from these studies should not be seen as a reason to defer HIV testing in this population. The benefits of HIV screening in cancer patients far outweigh any drawbacks, given the tremendous public health benefits of early diagnosis. We still have a long way to go in finding all the PLHIV in our country, and any opportunity to test is an opportunity to save a life.