Predicting prostate cancer recurrence

PHILADELPHIA, May 23 (UPI) -- U.S. researchers have linked low oxygen levels in prostate tumors to cancer recurrence.

Using a statistical model that accounted for such risk factors as tumor grade, prostate-specific antigen level and tumor size, researchers at the Fox Chase Cancer Center in Philadelphia found low oxygen -- hypoxia -- in the tumor before treatment to be a significant independent predictor of an increase in PSA levels.

PSA levels are considered markers of tumor recurrence in prostate cancer.

Dr. Aruna Turaka of Fox Chase Cancer Center in Philadelphia and colleagues custom-built a probe to monitor the amount of oxygen that prostate tumors and non-cancerous muscle tissue were receiving on 57 patients with low or intermediate risk of cancer -- just before the patients received a form of localized radiation therapy known as brachytherapy.

The researchers tracked the patients. Eight of the 57 patients experienced an increase in PSA levels following prostate cancer treatment. Overall, average muscle oxygenation was 12.5-times higher than that of the tumor.

"Now the goal is to apply the results to the clinic," Turaka said in a statement.

That requires both developing non-invasive screening methods to identify hypoxic tumors, as well as more potent anti-cancer weapons to target them, Turaka said.

The findings were presented at the American Society of Clinical Oncology annual meeting in Orlando, Fla.