Cancer drugs and diabetic retinopathy: a dangerous, underestimated association

Abstract

The worldwide growing prevalence of diabetes and cancer led to an increase in subjects affected by both these diseases that share several of the involved risk factors and have a complex, multifactorial etiopathogenesis. Cancer therapies could have harmful effects on several organs, particularly in subjects also affected by diabetes and its related comorbidities. Moreover, cancer diagnosis often monopolizes the attention of both patients and caregivers, thus reducing the attention to pre-existent diseases. Retinopathy is one of the most frequent microvascular complications of diabetes, accounting for about 5% of legal blindness worldwide. The retinal neurovascular unit is dysfunctional in diabetes and could represent a frail site when cancer therapies are administered. Nevertheless, the short- and long-term effects of the different anticancer molecules on retinal tissue, especially in diabetic subjects, are poorly known, and no specific recommendations on their prevention and management are available. In this review, we summarised the current data on this topic, focusing on the different cancer class drugs involved in retinal damage: anti-oestrogen, classical cytolytic chemotherapy (alkylating agents, taxanes, topoisomerase inhibitors, and antimetabolites), mitogen-activated protein kinase, tyrosine-kinase, and vascular endothelial growth factor inhibitors are the cancer drugs associated with retinal damage and visual disturbance. However, further studies are necessary to improve knowledge on the molecular and clinical relation between cancer therapies and retinopathy, in order to provide clinicians with evidence-based protocols to optimise the management of these conditions and minimise vision loss occurrence, impaired quality of life, and public health expense.