Salvage radiation therapy and the need for concurrent ADT; the value of the Decipher test

A paper given at the recent annual meeting of the American Society for Radiation Ocology (ASTRO) suggests that the Decipher genomic classifier may help to distinguish between treatment options for men in need of salvage radiation therapy after first-line radical prostatectomy.

The Decipher test is a laboratory test based on analysis of post-surgical prostate cancer tissue and provides a genomic assessment of the aggressiveness of the patient’s cancer that is different to the assessment of aggressiveness based on the patient’s Gleason score. The test may have its greatest value in assessing the aggressiveness of cancers post-surgery for men with pathological Gleason scores of 7 and either one other or no other indicators of risk.

Den et al. reported the results of a retrospective analysis of data from 166 patients receiving salvage radiation therapy at one of three different academic medical centers between 1990 and 2010 after their PSA levels had risen to a minimum of 0.2 ng/ml and therefore the men met the classical definition for biochemical recurrence post-surgery. They compared the men’s long-term outcomes based on their CAPRA-S scores and their responses to the Decipher genomic classifier.

They found that:

  • The patients’ survival c-index score for prediction of metastasis at 5 years after salvage radiation therapy was
    • 0.87 using the Decipher test
    • 0.62 based on the patients’ CAPRA-S score
  • Cumulative incidence of metastasis at 5 years after salvage radiation therapy was
    • 2.8 percent for men with low Decipher scores
    • 17 percent for men with low CAPRA-S scores
    • 5.8 percent for men with intermediate Decipher scores
    • 2.3 percent for men with intermediate CAPRA-S scores
    • 33.5 percent for men with high Decipher scores
    • 15 percent for men with high CAPRA-S scores
  • On multivariate analysis, the Decipher score was the only independent predictor of risk for metastasis (with a hazard ratio of 1.59 for a 10 percent unit increase in risk score; P = 0.0017).

The authors conclude that:

  • Among men given salvage radiation therapy for biochemical recurrence post-surgery, the Decipher genomic classifier “is a powerful predictor of metastasis”.
  • Patients with a low Decipher score have an excellent prognosis with salvage radiation therapy alone and may be able to avoid the use of neoadjuvant or adjuvant androgen deprivation therapy (ADT).
  • Patients with a high Decipher score are at highest risk for metastasis and failure of salvage radiation therapy alone, and may therefore benefit from concurrent neoadjuvant or adjuvant ADT.

Now it does have to be acknowledged that these data all come from a retrospective analysis of patients treated over a period of some 20 years, and so there are issues of selection bias that could be affecting the data. It would be helpful to have data from some form of prospective study — based on data from a more recent cohort of surgical patients — to confirm the results reported here.

For additional information on some of the details of this study, see this link to a report on the Clinical Laboratory Products Magazine web site. It is of some interest to note the unusually high representation of men of African American ethnicity in this study (53/166 patients or 32 percent).

One Response

  1. Your readers may be interested in my previous commentary on this.

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