Does colour vision deficiency reduce someone’s chances of surviving bladder cancer?

New research by US scientists has explored the effect of colour vision deficiency (CVD) on bladder and colorectal cancer survival.

Writing in Nature Health, scientists from Standford University, Colombia University and Beaumont Health reported that there were no significant differences in survival rates between colorectal cancer patients with and without CVD.

However, patients with CVD and bladder cancer had a reduced survival probability and 20-year mortality risk when compared to bladder cancer patients without CVD.

The scientists investigated the relationship between CVD and survival in these patient groups because people with CVD may have difficulty detecting one of the first symptoms of colorectal and bladder cancer – blood in the stool or urine.

Explaining why an effect was observed for bladder cancer but not for colorectal cancer, the authors highlighted: “because bladder cancer tends to present only with painless haematuria, the onus of disease detection is placed almost entirely on the patient observing blood in the urine, whereas colorectal cancer might be observed through other symptoms, or might be caught by routine screening.”

The researchers used data from an electronic health records research network (TriNetX) – a network aggregates de-identified electronic health records from several major health organisations within the US and other countries worldwide – as the basis of the study.