Cancer Treatment Today

Prostate cancer is newest condition in which a test that purports to classify risk of progression, recurrence and prognosis to help select therapy’ Oncotype prostate is another one. Before it can be considered for routine clinical ise, many hurdles remain. One is that it is a proprietary test that was developed and studies bin-house. Confirmation by outside, unbiased researchers is needed. More improtantly, it is based on fairly limited data and is retrospective;y validated. One msut show that it makes a difference when used prospectively.

Cuzick and his colleagues used the Prolaris genetic test to predict prostate cancer-specific mortality in a cohort of 337 patients who were diagnosed with clinically localized prostate cancer between 1990 and 1996. The Prolaris test is based on a panel of 46 genes, most of which are involved in cell cycle progression and cell growth. By measuring the capacity of prostate cancer tissue’s ability to divide and grow, the test can be used to assess whether a patient has a relatively indolent or a relatively aggressive form of prostate cancer using standard prostate tumor tissue of the type available to pathologists after TURP or after radical prostatectomy.

Data from the study by Cuzick et al. (“Prognostic value of a cell cycle expression profile score among men with conservatively treated localized prostate cancer”) showed that:

• Prolaris was capable of accurate prediction of prostate cancer-specific mortality with very high statistical significance (P = 1 x 10^-21).
• 25 percent of patients in this cohort had a “favorable” Prolaris score and  a 98.5 percent probability of surviving their cancer over a 10-year period.
• 25 percent of patients in this cohort had an “unfavorable” Prolaris score and a 42.4 percent probability of surviving their cancer over a 10-year period.
• Prolaris was superior to the Gleason score, baseline PSA levels, and other prognostic factors in predicting prostate cancer-specific mortality.

In theory, these data suggest that the Prolaris test should be capable of discriminating between good and poor candidates for active surveillance; however, additional hurdles remain to be overcome and it should not be considered proven or medically necessary at this time.

Brimo, F, Montironi, R, Egevad, L, et al. Contemporary grading for prostate cancer: implicationsfor patient care.Eur Urol  . 2013 May;63(5):892-901.