ASCO PROSTATE: Androgen Receptor Test Predicts Risk of Prostate Cancer Metastasis

KISSIMMEE, Fla., Feb. 26 -- A test that tallies the number of androgen receptors in a single prostate cancer cell may be an effective predictor of disease metastasis, said researchers here.

The test, which relies on quantitative immunofluorescence to measure androgen receptors and other molecular markers, demonstrated a sensitivity of 84% and specificity of 75% for predicting clinical progression in five years of definitive surgery, said Michael Donovan, M.D., Ph.D., of Aureon Laboratories in Yonkers, N.Y., which developed the assay.

Dr. Donovan said his results were based on androgen receptor analyses conducted on prostate cancer tissue from 758 men who had a radical prostatectomy at Memorial Sloan-Kettering Cancer Center from 1985 through 2003. He reported the findings at a prostate cancer symposium.

"We have created a highly sensitive predictive test for prostate cancer, similar to those available for breast cancer, that can be used to predict disease progression and potentially impact its course," Dr. Donovan said at a press briefing.

He and colleagues first used quantative immunofluorescence to assess a number of molecular markers in a "training set" comprised of half the tissue samples from the Memorial Sloan-Kettering patients. They identified four clinical factors-Gleason grade at biopsy and at prostatectomy, lymph node status, and seminal vesicle invasion. They also identified one molecular marker, the number of androgen receptors present within tumor cells that were positive for Racemase antibody.

Using a template with those markers, they analyzed a validation set comprised of the remaining tissue samples from the Memorial Sloan-Kettering patients and determined that the androgen receptors present were significant predictors of metastasis at five years (P