Genomic test identified men at high risk for prostate cancer recurrence

Researchers in Canada have developed a genomic test to identify patients with prostate cancer who are at high risk for recurrence after surgery or radiotherapy, according to findings presented at the European Society for Radiotherapy and Oncology.

“Men who fail treatment within 2 years may be at the highest risk of dying from their prostate cancer,” Robert Bristow, MD, a clinician-scientist at the Princess Margaret Cancer Centre in Toronto, said in a press release. “Existing methods for identifying high-risk patients are imperfect, so new tests are required that are better at predicting which patients will have their cancer recur.”

Bristow and colleagues from the Ontario Institute of Cancer Research reportedly developed a genetic “signature” based on the DNA of a patient’s prostate cancer that can accurately predict treatment failure in patients undergoing radiotherapy or surgery.

To evaluate the efficacy of the genomic test, researchers collected biopsied tissue from 126 men predicted to be at moderate risk for cancer recurrence. The participants then underwent a regimen of image-guided radiotherapy and were followed up for a median of 7.8 years.

The researchers analyzed the tumor DNA using array comparative genomic hybridization, which identifies missing or abnormal sections of DNA. Based on this information, they were able to identify the genetic signatures that are indicative of high and low risk for cancer relapse.

Bristow and colleagues then replicated the signature test the on a second group of 150 patients, also at moderate risk for recurrence, and who subsequently had their tumors resected by radical prostatectomy. The results seen in this group were similar to those seen in the original group.

A secondary analysis evaluated the prognostic utility of tumor oxygen content measurement. They found that, among the men treated with image-guided radiotherapy, tumors with high levels of hypoxia were associated with poor survival outcomes.

According to Bristow, further research is needed to validate the test during the next 2 to 3 years in different and larger groups of patients.

“This is the first report of a test using this information derived from biopsy samples that can predict with close to 80% accuracy which men are at high or low risk of their prostate cancer recurring,” he said. “If all goes well, then this will lead to a new test for cancer patients that can be turned around in 3 days and will tell doctors which patients will do well with local treatment alone — surgery or radiotherapy — and which will need extra treatment.”

For more information:
Bristow R. Abstract #O-0139. Presented at: The European Society for Radiotherapy and Oncology (ESTRO) 33; April 4-8, 2014; Vienna.

Disclosure: The researchers report no relevant financial disclosures.