A systematic review and meta-analysis of mortality in anal cancer patients by HIV status

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Introduction

Cancer is a common comorbidity among people with human immunodeficiency virus (HIV; PWH). This disease can be divided into acquired immunodeficiency syndrome (AIDS)-defining and non-AIDS-defining cancers [1] . PWH frequently present with more advanced stages of cancer, impacting treatment outcomes [23] . Advancements in HIV treatments, such as highly active antiretroviral therapy (HAART), which have been widely available in developed countries since 1996, have allowed PWH with access to treatment to have life expectancies similar to people without HIV (non-PWH) and to spend less time in an immunocompromised state. The increase in life expectancy has paradoxically resulted in higher rates of diagnosis of non-AIDS-defining cancers, such as anal cancer (AC) [4] .

Historically, AC has been considered to be a relatively rare malignancy, comprising 2–4% of all cancers of the colorectum and anus, and primarily affecting women. However, the incidence of AC has recently increased in developing countries, particularly among young men and men who have sex with men [5] . AC shares more pathophysiologic similarities with genital malignancies than with other gastrointestinal tract cancers, and its increased incidence is thought to be associated with increased transmission of HIV and human papilloma virus [67] . Traditional treatments for AC may have different effects among PWH compared to non-PWH due to their compromised immune systems, thereby impacting clinician treatment choice and patient risk of adverse events [7] .

This meta-analysis utilized literature published in the post-HAART era (1996 to present) to explore the association between HIV status and the risk of mortality in adults diagnosed with AC. Previous studies have suggested that PWH are at higher risk of mortality following AC diagnosis, although this finding has not been universal [78] . While several studies found that PWH have shorter median survival times compared to non-PWH following AC diagnosis, a recent systematic review reported no statistically significant differences in colorectal cancer mortality rates between persons with and without HIV [9] . A 2014 systematic review looked at the incidence, clinical signs, and outcomes in PWH diagnosed with colorectal cancer and AC but did not include a meta-analysis, and a 1999 study conducted a systematic review and meta-analysis of colorectal cancer and HIV status but did not evaluate AC [49] . To our knowledge, a meta-analysis has not been conducted on the association between HIV status and overall survival in patients with AC.

Our hypothesis was that PWH would have a higher risk of mortality compared to non-PWH following AC diagnosis in the post-HAART era. Our finding contributes to the published literature by assessing the aggregate data on AC patient outcomes in both PWH and non-PWH.