Evaluation of Treatment Disparities in People Living with HIV and Cancer (ETHIC): A Multicentre, Retrospective Observational Cohort Study

Abstract

Background: People living with HIV (PLWH) have up to a 2-fold increase in risk for non-AIDS defining malignancies (NADM). Data from the United States has demonstrated suboptimal cancer treatment provision and increased cancer specific mortality in PLWH compared to the general population. It is unclear if this association remains in the Canadian setting and in the context of modern antiretroviral and cancer therapies. Objectives: We aimed to determine if there was a difference in the proportion of PLWH receiving standard of care (SOC) cancer treatment compared to matched controls. We also explored whether factors associated with HIV disease control affect provision of treatment and examined efficacy and safety of chemotherapy and radiotherapy. Methods: This was a retrospective 1:1 matched cohort study performed at two large Canadian tertiary care centres. We included PLWH with a first diagnosis of anal, lung, prostate or hepatocellular carcinoma between 2010 and 2019. We compared proportions receiving SOC treatment in each cohort in the whole population and divided by HIV status. We defined SOC cancer treatment based on local and international guidelines, Health Canada approvals, and treatment funding criteria in Ontario and Quebec. Results: We evaluated 50 PLWH and 50 controls with cancer matched for age, cancer type and stage, year of treatment and treatment location. Anal carcinoma was the most frequent cancer type included in our analysis (40%). There was no difference in the primary outcome of receiving SOC treatment between cohorts (82% vs 86%, p=0.774) although there was numerically less provision of SOC treatment in the subgroup of PLWH with lung cancer (56% vs 78%). Baseline CD4+ T-cell count, viral load, and antiretroviral regimen did not appear to affect whether SOC treatment was provided. There was no difference in cancer treatment safety or efficacy in our population, except for those with non-small cell lung cancer (n=18) where there appeared to be less response (33% vs 71%) and less toxicity (25% vs 40%) to treatment amongst PLWH. Conclusions: PLWH appear to have similar provision of SOC cancer treatment to matched controls, except for those diagnosed with lung cancer who received SOC treatment less frequently, and with a lower observed response to therapy. This discrepancy warrants further investigation. Treatment of NADM with SOC treatment appears safe and effective in PLWH.