Dr. Richard Stock and colleagues have written a concise, informative article demonstrating that we are still far from establishing the role of radiation in node-positive prostate cancer. The real question for me, as an overworked clinician, is whether any patient benefits from pelvic radiation.
The authors cite encouraging studies from the Mayo Clinic, Radiation Therapy Oncology Group (RTOG), and the Hospital of the University of Pennsylvania suggesting that some node-positive patients may be curable, and that pelvic or prostate radiation and/or hormonal treatment may be beneficial.[1-3] I doubt it.
No Plateau in Sight
When analyzing studies, it is crucial to determine where the freedom-from-failure curves are headed, as opposed to comparing tabular data taken at one time point. What I look for in reports is whether the freedom-from-failure curves plateau at some point, indicating that some percentage of patients are being cured.
Unfortunately, such a plateau is lacking in the large series with longer follow-up, even for the most favorable patient subgroups (Figure 1).[1-4] Patients with positive nodes, regardless of how favorable their other features may be, apparently all develop systemic failure if followed long enough.
The University of Pennsylvania study of hormonal therapy and pelvic radiation was especially encouraging, showing an apparent plateau in the freedom-from-progression curve in the initial report published in 1995. However, with longer follow-up, the freedom-from-failure line has started to fall, with no plateau in sight (see Figure 1).
A Waste of Patients Time and Societys Resources
Pelvic or prostate radiation is probably a waste of patients time and societys resources. As demonstrated by Leibel and colleagues, radiation to the prostate itself does not suppress metastatic disease. And symptomatic local progression is not common enough to warrant prostate radiation to prevent local tumor progression.
I doubt that pelvic or prostate radiation offers any node-positive patients the chance for cure, and I discourage patients from having it. I think that such men are better off delaying therapy until they develop symptomatic disease, or enrolling in trials designed to test the value of newer therapeutic strategies.