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Does Pelvic Irradiation Play a Role in the Management of Prostate Cancer?

Does Pelvic Irradiation Play a Role in the Management of Prostate Cancer?

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.[2] 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 Society’s Resources

Pelvic or prostate radiation is probably a waste of patients’ time and society’s resources. As demonstrated by Leibel and colleagues, radiation to the prostate itself does not suppress metastatic disease.[4] 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.

References

1. Lawton CA, Winter K, Byhardt R, et al: Androgen suppression plus radiation versus radiation alone for patients with D1 (pN+) adenocarcinoma of the prostate (results based on a national prospective randomized trial, RTOG 85-31). Radiation Therapy Oncology Group. Int J Radiat Oncol Biol Phys 38:931-939, 1997.

2. Whittington R, Malkowicz SB, Machtay M, et al: The use of combined radiation therapy and hormonal therapy in the management of lymph node-positive prostate cancer. Int J Radiat Oncol Biol Phys 39:673-680, 1997.

3. Zincke H, Bergstralh EJ, Larson KJ, et al: Stage D1 prostate cancer treated by radical prostatectomy and adjuvant hormonal treatment: Evidence for favorable survival in patients with DNA diploid tumors. Cancer 70:311-323, 1992.

4. Leibel SA, Fuks Z, Zelefsky MJ, et al: The effects of local and regional treatment on the metastatic outcome in prostatic carcinoma with pelvic lymph node involvement. Int J Radiat Oncol Biol Phys 28:7-16, 1993.

 
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