Utility of genomic scoring in prostate cancer

The authors evaluated a scoring system known as genomic classifier (GC) score that could indicate spread of cancer in prostate canecr patients after surgery and radiation therapy.

Prostate surgery and radiation therapy are common treatments in prostate cancer. Prostate surgery involves surgically removing the prostate gland in men with prostate cancer. Radiation therapy directs a beam of radiation at the tumor site in order to kill cancer cells with minimal damage to healthy cells. Radiation therapy is often performed following surgery. It may be possible for some patients to wait on radiation therapy until they see a rise in prostate specific antigen (PSA, a protein present in prostate cancer), an indication that the cancer has returned. Currently there is no effective way to predict which patients may see a return of their cancer.

The GC score is a measure of activity of certain genes within the tumor. This score can be used to predict a patient’s risk of cancer spread. It uses a scoring system between 0-1. The lower the score, the lesser is the risk of cancer spreading to other parts of the body (metastasis). 

The current study examined whether the GC score could help in the decision of when to administer radiation therapy following prostate surgery by predicting if the cancer would spread.

Data from 188 patients were used in this study with a follow-up of 8-10 years. 51.1% of patients had radiation therapy following surgery. 47.3% had radiation therapy after a post-surgery rise in PSA. Patients were divided into three groups depending on their GC score: low (less than 0.4); average (0.4-0.6) and high (more than 0.6).

Overall, 10% of patients had metastasis. The average time to develop metastasis was 3 years.

None of the patients who had low GC scores developed metastasis after 5 years following radiation therapy. The occurrence of metastasis at 5 years was 9% in patients with average GC scores and 29% in patients with high GC scores.

Within the high GC score, patients who received radiation therapy following surgery had a 6% occurrence of metastasis at 5 years. Those who received radiation therapy after a rise in PSA had a 23% occurrence of metastasis at 5 years. 

The authors concluded that GC score could be a useful tool to determine the chances of metastasis in prostate cancer patients receiving radiation therapy following prostate surgery.