Cancer Treatment Today

Prostate Px has not been determined safe and effective.

Systems pathology, an approach that combines cellular and biologic features to standard
clinical parameters such as age, clinical or pathologic stage, grade, percent of cancer on
biopsy cores, and prostate-specific antigen or its derivatives, is a recently proposed approach to
estimate the probability of disease progression, either prior to or following prostatectomy.

Under the direction of Aureon Laboratories, a multi-institutional group developed and validated a pretreatment prediction model along tese lines, ProstatePx+. The model uses 3 clinicopathologic variables, 1 biomarker variable, and 2 advanced imaging features from the biopsy tissue. It predicted clinical failure (as defined earlier) within 8 years of radical prostatectomy. The model was validated on an independent cohort of patients and yielded a concordance index of 0.73.

This test has not been cleared (or reviewed) by the U.S. Food and Drug. Administration (FDA). The company’s postion is that Prostate Px does not require FDA approval. The test is considered a laboratory developed test (LDT) and is performed in Aureon’s CLIA-certified, College of American Pathologists (CAP) – accredited, New York State-regulated laboratory.

In an editorial accompanying the 2008 article by Donovan et al., Klein raises a number of questions. A major question raised is whether the differences with these new models have sufficient clinical relevance to justify the extra effort, expense, and expertise needed for the systems pathology approach. He comments that additional studies are needed to understand the incremental value of this new information.

The problem for clinical use is the same that all predicitve models face – proving clinical utility. It is not enough to show that a test corrresponds with prognosis. One must also show that making treatment decisions based on the test benefits patients. These studies have not yet been done.

Donovan MJ, Hamann S, Clayton M et al. Systems pathology approach for the
prediction of prostate cancer progression after radical prostatectomy. J Clin Oncol
2008; 26(24):3923-9.

3Donovan MJ, Khan FM, Fernandez G et al. Personalized prediction of tumor
response and cancer progression on prostate needle biopsy. J Urol
2009; 182(1):125- 32.

Cordon-Cardo C, Kotsianti A, Verbel DA et al. Improved prediction of prostate cancer recurrence through systems pathology. J Clin Invest 2007; 117(7):1876-83.

Klein EA, Stephenson AJ, Raghavan D et al. Systems pathology and predicting outcome after radical prostatectomy. J Clin Oncol 2008; 26(24):3916-7.