Researchers developing a urine “sniff test” for prostate cancer believe that, once perfected, their method will help doctors to reduce unwarranted biopsies for diagnosing the disease. However, biopsies are expensive, uncomfortable, and carry the risk of infection. Unfortunately, thousands of men undergo the procedure – which involves inserting a needle into the prostate gland to remove pieces of tissue for analysis – only to discover that they do not require cancer treatment.
Scientists are therefore investigating various alternative ways to improve prostate cancer diagnosis without having to rely on biopsies.
One approach has been inspired by studies that show that dogs can detect volatile organic compounds in the urine of men with prostate cancer. One such study showed that the animals could sniff out prostate cancer with 98 percent accuracy.
The researchers behind the new study believe that they have identified the molecules that likely give the urine of men with prostate cancer its unique scent, and they have developed a chemical sniff test to detect them.
Senior investigator Prof Mangilal Agarwal, an associate director of research and development at Indiana University-Purdue University Indianapolis, has been developing a sensor to detect hypoglycemia (low blood sugar) in human breath.
He and his colleagues – including Dr Amanda Siegel, co-presenter of the study results – were inspired by the success of the dog studies and decided to investigate which molecules might be involved. “If dogs can smell prostate cancer, we should be able to, too,” says Dr Siegel.
The researchers noted that some previous studies had experienced problems with chemical degradation. Thus, to better preserve the samples during analysis, they added sodium chloride and neutralised their pH.
Using gas chromatography-mass spectrometry to analyse the volatile organic compounds in the air above the urine samples, the team found a set of small molecules that appear to be unique to prostate cancer.
The molecules were present in 90 percent of samples from men who were subsequently found to have prostate cancer, but they were not present in samples from men who did not have it.
The researchers are already planning to validate their findings with a large-scale study involving several health centres. They also hope to compare their findings with results obtained from dogs, with the help of a local dog trainer.
They suggest, if these further tests confirm their findings, that their chemical sniff test will be available for clinical use within the next few years.
Dr Amanda Siegel said that “We hope our research will help doctors and patients make better-informed decisions about whether to have a biopsy, and to avoid unwarranted procedures.”
