A Medical Device Daily

A newly discovered blood biomarker is being touted as giving researchers even further insight on the spread of prostate cancer.

The biomarker, which was discovered by Shahrokh Shariat, MD, chief urology resident at the University of Texas Southwestern Medical Center (Dallas), is said to enable close to a 98% accuracy of determining the spread of the aforementioned cancer into the lymphnode area.

Shariat and his research team’s study is being published in the March 1 issue of Clinical Cancer Research, a journal of the American Association for Cancer Research (Philadelphia). It was funded through a grant from the National Institute of Health (NIH).

“For prostate cancer, we have hit the limit of our ability to classify risk in these patients before initial surgery. We currently use prostate specific antigen, Gleason grade and a rectal exam, but the predictive value of those three tests is inadequate for predicting what cancers will spread. Conventional imaging modalities used for clinical staging in prostate cancer are inadequate to detect small but clinically significant lymph node metastases.” Shariat said in a statement.

He added: “Although it is recognized that pelvic lymphadenectomy can provide important staging and prognostic information, it is still not clear in whom this procedure should be done.”

“Doing pelvic lymphadenectomy on all patients is not universally practiced, as this procedure could be time-consuming and is not without morbidity. As such, it would be of tremendous benefit to have an accurate blood marker that identifies patients in whom pelvic lymphadenectomy should be done,” said co-author Claus Roehrborn, MD, professor and chairman of urology at the University of Texas Southwestern Medical Center.

When cancer spreads beyond a solid tumor, it often does so at a microscopic level that typically can’t be identified by conventional imaging methods such as CT scans. The new blood test measures levels of endoglin, a plasma biomarker that has been previously shown to predict the spread of colon and breast cancer. In this study, researchers concluded for the first time that endoglin could help predict whether a patient’s prostate cancer would spread beyond the solid tumor site into their lymph nodes.

The research team observed a little more than 400 patients who had undergone surgery to remove both their prostates and associated pelvic lymph nodes. The team measured the levels of plasma endoglin using a blood test. Higher plasma endoglin levels were associated with an increased risk of cancer spread to the lymph nodes. Each 1 ng/mL increase of plasma endoglin increased the risk for cancer spread into the lymph nodes by 17%.

When researchers added endoglin levels to their usual methods of prediction, the accuracy improved from 89.4% without endoglin to 97.8%. Blood levels of endoglin may allow doctors to predict the risk of cancer spread at an earlier stage and with higher accuracy than available methods.

The study authors said that despite recent gains in the management of cancer only 25% to 30% fail primary curative treatment such as radical prostatectomy and radiotherapy. This is often occurs because of the spread of cancer cells beyond the original tumor site.

The study further states that use of plasma endoglin could help identify patients at risk for lymph nodes metastasis who should undergo pelvic lymphadenectomy. In addition, it could spare patients at low risk of lymph node metastasis the potential morbidity of an unnecessary lymphadenectomy

The researchers said the retrospective study, the standard lymph node sampling and the small number of events support the need for multi-center, prospective studies before the clinical use of endoglin as a marker for predicting lymph node metastasis in patients with clinically localized prostate cancer.

“Ultimately endoglin will need to be combined with three of four other markers to predict risk with greater certainty,” Shariat said. “The problem with biomarkers is that there is a tremendous variability among patients, but this moves us forward from what we were able to do with imaging and with our other commonly used methods.”