Impact of colour vision deficiency on bladder and colorectal cancer survival

Abstract

Patients with colour vision deficiency (CVD) may not see blood in urine or stool, often the first sign of bladder or colorectal cancer, respectively. Here we sought to identify whether patients with bladder or colorectal cancer and CVD have worse outcomes when compared to matched patients without CVD, using an electronic health records research network (TriNetX). A total of 135 patients with CVD and bladder cancer showed shorter overall survival (χ² = 4.85, P = 0.028) as compared to 135 matched patients without CVD. There was no significant difference among 187 patients with colorectal cancer and CVD, and controls. This suggests that patients with bladder cancer and CVD may be at risk of reduced survival. This is a hypothesis-generating paper that should raise clinicians’ diagnostic suspicion for bladder cancer in patients with CVD and prompt further investigation into whether screening for bladder cancer should be introduced for high-risk individuals with CVD.

Fattah, M., Alsoudi, A.F., Mruthyunjaya, P. et al. Impact of colour vision deficiency on bladder and colorectal cancer survival. Nat. Health 1, 113–119 (2026). https://doi.org/10.1038/s44360-025-00032-7