A simple test which measures the level of the enzyme telomerase in urine could be used effectively to detect bladder cancer, a study suggests.
Smoking is linked to an increased risk of bladder cancer
The Italian researchers say their test proved to be around 90% accurate.
In the Journal of the American Medical Association, they say their test should be used more widely on smokers and others prone to developing the disease.
Bladder cancer is the fourth most common form of the disease in UK men, and the tenth most common in women.
Each year, there are more than 10,700 new cases, leading to around 4,900 deaths.
However, when the disease is diagnosed and treated in the early stage, the chances of survival are good.
Established approaches for detecting bladder cancer are either invasive and costly, or have limited sensitivity.
Researchers at the Morgagni-Pierantoni Hospital, Forlė, Italy, studied 218 men, 134 of whom had been diagnosed with bladder cancer.
They tested the men's urine for levels of the enzyme telomerase, which is present in almost all human cancer cells but only rarely in non-cancerous cells.
A diagnosis of bladder cancer was based on tissue sample tests and visual examination of the urinary tract.
The enzyme check was compared to urine cytology - which looks for cancer cells in urine, but which the researchers say has limited sensitivity, especially for those with low-grade cancers.
The enzyme test was shown to be 90% accurate in detecting people who did have cancer, and 88% accurate in results for those who did not.
Telomerase activity level checks were found to be as accurate for bladder cancer patients with low-grade tumours or for those whose cytology tests were negative.
Writing in JAMA, the researchers led by Dr Maria Aurora Sanchini, said: "The test we developed requires a small amount of urine; is non-invasive, inexpensive, and easy to perform; and permits a quantitative evaluation of telomerase activity in cellular extracts from urine."
But she added: "It is not recommended for use in routine screening programs because of the low incidence of bladder cancer, and should be aimed at high-risk subgroups.
"Specifically, smokers have about a three-fold increased risk of developing bladder cancer compared with non-smokers."
Cancer Research UK's Professor Gareth Williams said: "The detection of bladder cancer currently depends on invasive and costly examination, so there is therefore an urgent requirement for a simple non-invasive test.
"This study shows that measuring telomerase activity in urine samples provides a highly sensitive and specific approach for the detection of bladder cancer.
"Further prospective studies on larger patient populations are now required to follow up on these exciting preliminary findings and to determine the clinical utility of this test in the primary diagnosis and monitoring of bladder cancer."