The Decipher test is a genomic classifier developed for men diagnosed with prostate cancer to assess the tumor’s underlying biology and predict its aggressiveness. The test provides a personalized risk assessment that goes beyond traditional clinical and pathological factors, such as the Gleason score or Prostate-Specific Antigen (PSA) levels. Its purpose is to help physicians and patients make informed decisions about treatment intensity and timing. By analyzing the tumor’s genetic makeup, Decipher helps determine the likelihood that the cancer will progress or spread over time. This molecular insight aids in deciding between monitoring the cancer or pursuing immediate, definitive treatment.
The Science Behind Decipher Testing
The Decipher test operates by analyzing the expression levels of 22 specific genes within the prostate tumor tissue. This tissue is typically obtained from an earlier biopsy or from the prostate removed during surgery. These 22 genes were selected because their activity is linked to known biological pathways that drive tumor aggressiveness, such as cell cycle progression, immune response, and the potential for cancer cells to form new blood vessels.
The laboratory process involves extracting the ribonucleic acid (RNA) from the formalin-fixed, paraffin-embedded (FFPE) tissue sample. The expression level of each of the 22 genes is then measured using advanced microarray technology. This raw genetic data is fed into a specialized algorithm that weighs the contribution of each gene’s activity to the overall risk of disease progression. The algorithm translates this complex molecular profile into a single, continuous numerical result known as the Decipher Score, which ranges from 0 to 1.0.
Clinical Application of the Test
The Decipher test is utilized in specific clinical scenarios where a patient’s risk profile remains uncertain based on standard measures alone. One primary application is for men newly diagnosed with localized prostate cancer. For these patients, the test helps determine whether they are appropriate candidates for active surveillance, which involves close monitoring, or if they should proceed with immediate treatment like surgery or radiation. The test is particularly helpful for those with intermediate-risk disease, where the choice between surveillance and definitive therapy is often difficult.
The second major application is in the post-prostatectomy setting, after the prostate gland has been surgically removed. In this scenario, the test is performed on the surgical tissue to predict the risk of the cancer returning, spreading (metastasis), or causing cancer-specific mortality. The Decipher score helps doctors decide if a patient with high-risk features found during surgery would benefit from additional treatments, such as adjuvant radiation or hormone therapy.
Interpreting the Decipher Score
The numerical Decipher Score, ranging from 0.0 to 1.0, is a direct estimate of the tumor’s genomic risk. A score closer to 0.0 indicates a low genomic risk, while a score nearer to 1.0 signifies a high genomic risk. The continuous score is usually grouped into three main risk categories: Low, Intermediate, and High.
A score below 0.45 is generally considered Low Risk, suggesting a favorable long-term prognosis. Patients in this category have a low likelihood of developing metastasis or experiencing cancer-specific mortality. An Intermediate Risk score falls roughly between 0.45 and 0.60, indicating a moderate chance of the disease progressing.
A score above 0.60 is classified as High Risk, which is associated with a substantially increased probability of the cancer spreading. For men with high scores, the risk of metastasis at 10 years can be several times higher than for those with low scores. This genomic information provides an estimate of the tumor’s future behavior, which is independent of the initial clinical staging or Gleason grade. The test helps quantify the likelihood of adverse outcomes, such as a 5-year risk of clinical metastasis or a 10-year risk of prostate cancer-specific mortality.
Influence on Treatment Decisions
The genomic risk stratification provided by the Decipher score translates directly into specific treatment recommendations. For men newly diagnosed with localized disease, a Low Decipher Score can reinforce the decision to pursue active surveillance. This allows patients to avoid the side effects of immediate surgery or radiation. Conversely, if a patient with low- or intermediate-risk disease based on traditional factors receives a High Decipher Score, this new information may prompt a shift toward immediate, definitive treatment.
In the post-prostatectomy setting, the score helps guide the intensity of follow-up care. A patient with adverse pathological features but a Low Decipher Score may be managed with observation, delaying or avoiding additional therapy. For those with a High Decipher Score, the data supports the intensification of therapy, such as receiving early salvage radiation therapy, possibly combined with hormone therapy, to reduce the risk of distant spread. This personalized approach helps reserve more aggressive treatments for the patients who are most likely to benefit from them.