Test Predicts Prostate Cancer Outcome from Needle Biopsy Tissue

A molecular diagnostic test is the strongest predictor of cancer death for prostate cancer patients managed through watchful waiting.

The Prolaris test consists of a panel of 46 genes, the majority of which are involved in cell cycle progression (CCP) and cell growth. Prolaris testing examines standard prostate tumor tissue available to pathologists to assess quantitatively whether a patient is likely to have a slow growing form of prostate cancer or a more aggressive cancer.

In a study carried out in Utah (USA), the test was found to be the most effective predictor of aggressiveness of prostate cancer and prostate cancer death. Prolaris CCP scores were analyzed for 352 men whose clinically localized prostate cancer was diagnosed by needle biopsy. The predictive nature of the Prolaris CCP score in biopsies was compared to accepted clinical variables including Gleason score, baseline PSA, age, clinical stage, and the extent of the disease.

The study determined that the Prolaris CCP score was the strongest predictor of cancer death outcome (p = 1.4 X 10^-10) and more significant than either the Gleason score or PSA.

Prolaris is a product of Myriad Genetics Inc. (Salt Lake City, UT, USA). The company believes the market need for the product stems from the limited ability of current markers to predict accurately prostate cancer aggressiveness at time of biopsy. Prolaris testing can also be used to estimate the risk of prostate cancer recurrence in patients who have already undergone a radical prostatectomy or transurethral resection of the prostate.

A presentation describing the prognostic value of the 46-gene cell cycle CCP RNA signature for prostate cancer death was given on Saturday, June 4, 2011, at the American Society of Clinical Oncology (ASCO) Annual Meeting in Chicago (IL, USA).

"[The] findings are of great potential clinical significance," stated Jerry Lanchbury PhD, Chief Scientific Officer of Myriad Genetics, Inc. "We believe that this latest study provides very strong evidence that the Prolaris test has an important role to play in defining the aggressiveness of a given prostate cancer, at the point of biopsy, and therefore provides essential guidance to physicians and their patients on the appropriate course of treatment."

Many men diagnosed with prostate cancer have indolent disease that can be safely monitored with active surveillance, whereas some patients have aggressive cancer and need immediate treatment. All men diagnosed with prostate cancer must decide whether to have aggressive therapy such as radiation or radical prostatectomy, which has potentially significant complications such as incontinence and impotence, or to monitor the disease through active surveillance.

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