After seven months of extensive training, scientists in United Kingdom have managed to make good use of dogs' inordinate interest in human urine by utilising their "super-sensitive noses" to detect signs of bladder cancer, a report said.

Dermatologist Carolyn Willis at Amersham Hospital, UK, and her team trained six dogs of different breeds to detect the urine of patients with bladder cancer, a report published in 'Nature' said.

Researchers at the Hospital were inspired to train dogs for the cause as they believe that cancer cells release molecules into the urine that have a characteristic smell of the disease, it said.

One of the first cases to reach the medical literature reported a woman who had gone to the doctor after her dog started sniffing suspiciously around a skin sore. It turned out to be a malignant tumour, it said.

Trainers worked on the dogs for seven months and trained them to detect the unique odour signature of cancer, compared to those of infections, inflammation or blood, it said.

The trainers also coached the dogs to discriminate between the urine of cancer patients and those with other bladder conditions, it said.

After the training was over, the dogs were asked to choose between laboratory dishes of seven types of urine and lie down in front of the one from a cancer patient, it said.

When the trained dogs were put to the test, they were correct over 40 per cent of the time, says Willis.

In one instance during the training, the dogs repeatedly chose the urine of a supposedly healthy patient. When doctors did further tests, they discovered a burgeoning kidney cancer, the report said.

Willis, however, acknowledges that the dogs are not expert enough to start routinely performing diagnoses, which need to be far more accurate. "None of us envisages dogs replacing doctors," she says.

Nevertheless, the researcher hopes to gradually sift through the molecules in patients' urine and use the dogs to help identify which ones are warning signs of bladder cancer.

These molecules could then be used to make diagnostic tests for use in the lab, the report added.