Detection of bladder cancer has been hampered by a lack of reliable, non-invasive tests
Detection of bladder cancer has been hampered by a lack of reliable, non-invasive tests, but there is hope on the horizon
Two new biomarkers could herald real advances in the non-invasive detection of bladder and prostate cancers, a leading Australian urologist says.
Returning from the recent American Urology Association Annual Meeting, Professor Henry Woo said a new urine-based gene expression test to monitor bladder cancer patients for recurrence, Cxbladder Monitor, represented a significant breakthrough.
“It’s vastly superior to anything we’ve got,” he told The Medical Republic.
A study presented at the conference analysed samples from 803 patients across 11 clinical sites in the United States. Patients were monitored with the test for either six months or a maximum of three cystoscopic evaluations.
According to the findings, the test had a sensitivity of 93% and a negative predictive value of 97%, and significantly outperformed existing urine-based tests evaluated across all stages and grades of tumour.
“Cxbladder Monitor greatly reduces the burden of cystoscopy on low-risk patients who are scheduled for clinical evaluation or can be used as a confirmatory negative adjunct to cystoscopy, thereby justifying the postponement of additional investigation,” the conference heard.
While further validation studies were needed, the test could be of great future benefit, provided it was reasonably priced, Professor Woo said.
“We’ve been lacking reliable non-invasive approaches, and things like urine cytology only pick up about 30% of bladder cancers,” Professor Woo said.
A second test launched at the conference, IsoPSA, detects cancer by identifying molecular structural changes in prostate-specific antigen, as opposed to current tests that simply measure the protein’s concentration in a patient’s blood.
The IsoPSA test can differentiate between high and low-risk prostate cancers, and tell them apart from benign conditions, its developers say.
Dr Woo said early evidence suggested the test was more effective than current PSA tests, and could potentially prevent unnecessary biopsies.
Because of the known limitations of the current PSA test, a recent uptick in PSA testing has been linked with overdiagnosis and unnecessary invasive treatment, which can be associated with complications, including infection, incontinence and erectile dysfunction, as well as anxiety.
While IsoPSA was definitely a step forward from the current test, Professor Woo cautioned it was not a silver bullet. It was important that clinicians framed all PSA testing as a risk assessment or triaging tool, rather than a diagnostic tool, he said.
While PSA tests examined a small subset of the hundreds of PSA isoforms, the IsoPSA gathered them all and measured them in aggregate, he explained.
However, the IsoPSA test is a long way from reaching Australian clinical settings at this stage. “We’re only just seeing the first clinical study with any numbers,” Dr Woo said.
Dr Woo has contacted IsoPSA researchers about an Australian collaboration on further studies. The response had been positive and it was now up to the research company as to where and how they proceeded, he said.
“All of us are eager to learn what it can do. “
