Mild kidney disease 'linked to increased cancer risk'

Even mild kidney disease is linked to an increased risk of developing and dying from cancer, according to a new study.

Researchers discovered the link using a “cystatin C” test which they said is more sensitive than the one commonly used in the NHS.

Using data from the UK Biobank alongside the simple blood test, the research, led by the University of Glasgow, found that mild kidney disease is associated with a 4% increased risk of developing cancer and a 15% increased risk of dying from cancer.

In people with more advanced kidney disease, researchers found a 19% increased risk in developing cancer and a 48% increased risk of dying from cancer.

This heightened risk of developing and dying from cancer was not identified when kidney function was estimated using serum creatinine – the test most commonly used in healthcare settings – to estimate a patient’s kidney function.

Researchers believe that if chronic kidney disease was recognised as an important risk factor for cancer, it may be that milder symptoms in patients with this condition would trigger earlier referrals, prompting earlier treatment and better outcomes for patients.

Dr Jennifer Lees, of the University of Glasgow, said: “Our research suggests that greater uptake of cystatin C testing could be used to improve patient outcomes by identifying cancer risks earlier, thereby increasing patients’ quality of life and chance of survival.

“Although cystatin C testing is available in most developed countries, it is more expensive than creatinine testing in many laboratories.

“However, we believe more widespread use could drive down the costs of testing and aid further research into identifying and addressing the factors responsible for worse cancer outcomes in people with kidney disease.”

Chronic kidney disease, characterised by gradual loss of kidney function over time, affects around 10% of the population.

Although kidney failure is relatively uncommon, mild kidney disease may be present in one third of the population, although it is usually asymptomatic, not routinely diagnosed and therefore monitored infrequently.

Cancer is already known to be more common in people with kidney failure, especially in people requiring dialysis or a kidney transplant.

Chronic kidney disease is also associated with premature cardiovascular disease and mortality.

Using cystatin C testing researchers are already able to show that mild kidney disease is associated with a 20-30% increase in risk of cardiovascular disease and early death, and this heightened risk is more pronounced in people with more advanced kidney disease.

Dr Lees said: “Our results show that mild kidney disease is clinically important in predicting cancer risk, as well as the risk of cardiovascular disease and early death.

“However, identifying this excess risk requires measurement of more sensitive markers of kidney dysfunction such as cystatin C.

“We were not able to see the same risk when using the less sensitive, but more routinely used, serum creatinine test.”

The study, Kidney function and cancer risk: an analysis using creatinine and cystatin C in a cohort study, is published in EClinicalMedicine.

The work was funded by the Scottish Government Chief Scientist Office, ANID Becas Chile, the Medical Research Council, the British Medical Association and the British Heart Foundation.