Dr. Den on Radiation Therapy in Prostate Cancer

Robert B. Den, MD, associate professor of Radiation Oncology, Thomas Jefferson University Hospital, discusses the use of radiation therapy as a treatment for patients with prostate cancer.

Currently in the field of prostate cancer, there is quite a lot of uncertainty as to which patients derive the most benefit from post-prostatectomy radiation, according to Den. Oncologists are also a bit unsure about the ideal timing for administering radiation. There is concern about initiating radiation therapy too early, as the treatment is associated with increased toxicity.

On the other hand, some researchers are worried that, by waiting too long to administer radiation, they could be missing a window of opportunity for potential benefit for a patient, as they are allowing the disease to spread too far before such aggressive therapy can provide the right benefit.

Three randomized clinical trials addressed some of these issues in the adjuvant radiation setting. While all 3 studies showed improvement in biochemical survival, only 1 of the trials demonstrated improvement in overall survival. Moreover, in the control arm of that study, approximately 50% of patients did not develop prostate-specific antigen (PSA) recurrence at 5 years. Thus, there is a lack of understanding as to which patients will develop recurrence, who will develop recurrence despite aggressive radiation therapy, and which patients will never develop recurrence. The biggest question there, says Den, is differentiating these groups of patients.

A more recent retrospective, multicenter study sought to determine if a genomic classifier could predict the development of metastatic disease in patients who received salvage radiation therapy for recurrent prostate cancer after radical prostatectomy. The data suggest that the genomic classifier is a strong predictor of metastases among this specific patient, accurately identifying men who are excellent candidates for systemic therapy due to their high risk of metastases.