New blood marker may predict prostate cancer spread

Feb 27, 2008

Researchers report finding a new blood biomarker that enables close to 98 percent accuracy in predicting the spread of prostate cancer to regional lymph nodes. Their study is published in the March 1 issue of Clinical Cancer Research, a journal of the American Association for Cancer Research.

When cancer spreads beyond a solid tumor, it often does so at a microscopic level that typically cannot 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.

“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.” said study author Shahrokh F. Shariat, MD, chief urology resident at the University of Texas Southwestern Medical Center.

“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 G. Roehrborn, MD, professor and chairman of Urology at the University of Texas Southwestern Medical Center.

Shariat and his colleagues observed 425 patients who had undergone surgery to remove both their prostates and associated pelvic lymph nodes. Researchers measured the levels of plasma endoglin using a commercially available 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 percent.

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

“Despite strides in the management of prostate cancer, approximately 25 percent to 30 percent fail primary curative treatment such as radical prostatectomy and radiotherapy. This is often due to spread of cancer cells beyond the original tumor site. Use of plasma endoglin could help identify patients at risk for lymph nodes metastasis who should undergo pelvic lymphadenectomy. In addition, it may spare patients at low risk of lymph node metastasis the potential morbidity of an unnecessary lymphadenectomy,” Shariat said.

The authors stressed that some limitations of this study should be noted. The retrospective study, the standard lymph node sampling, and the small number of events support the need for multicenter 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. 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,” Shariat said.

Source: American Association for Cancer Research

Explore further: Facility churns out radioactive agents to investigate the subcellular activity that drives disease

Related Stories

Can lightning strike an indoor pool?

27 minutes ago

Two swimming pool weather policies have surprised me in recent years. One was when I showed up to swim laps at an outdoor pool as it was beginning to drizzle. "Come on in," I was told; as long as there was no lightning, the ...

Another five things to know about meta-analysis

47 minutes ago

Last year I wrote a post of "5 Key Things to Know About Meta-Analysis". It was a great way to focus – but it was hard keeping to only 5. With meta-analyses booming, including many that are poorly done or ...

Recommended for you

Protein's impact on colorectal cancer is dappled

13 hours ago

Researchers at University of California, San Diego School of Medicine have discovered a cell signaling pathway that appears to exert some control over initiation and progression of colorectal cancer, the ...

Colon cancer: Taking a step back to move forward

22 hours ago

Recent Weizmann Institute studies are revealing a complex picture of cancer progression in which certain genes that drive tumor growth in the earlier stages get suppressed in later stages - taking a step ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.