Beyond The Abstract - Significance Of Whole-Pelvic Radiotherapy For High Risk Prostate Cancer Patients After Radical Prostatectomy

Main Category: Prostate / Prostate Cancer
Also Included In: Radiology / Nuclear Medicine;  Endocrinology;  Clinical Trials / Drug Trials
Article Date: 23 Dec 2007 - 0:00 PDT

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UroToday.com - To conduct the combination therapy of radiation and hormonal therapy for high-risk prostate cancer patients, the field, dose and fractionation of irradiation and the timing and method of hormonal therapy are the issues of controversy. Although the EORTC Radiation Oncology Group published guidelines for target volume in post-operative radiotherapy, they did not recommend routine pelvic lymph node irradiation.

On the contrary, several reports including RTOG 94-13 trial and the present study imply better efficacy of WPRT than PBRT. Greater dose of irradiation will be able to obtain better local control and the ASTRO consensus panel recommended 64 Gy or slightly higher for salvage radiotherapy. However, the optimal dose of adjuvant or salvage radiotherapy after radical prostatectomy seems still unknown and the advantage of hypofractionated salvage radiotherapy has not been confirmed. As for hormonal therapy, the optimal timing of hormonal therapy is not precisely determined. For untreated patients, similar to RTOG 94-13 study, the shrinkage of the prostate gland by hormonal therapy result in reduction of the radiation target volume, suggesting advantage of neoadjuvant hormonal therapy. On the contrary, adjuvant or salvage radiotherapy after radical prostatectomy, the size of radiation target would not change irrespective of neoadjuvant hormonal therapy. Concerning the method of hormonal therapy, total androgen blockade with LHRH agonist plus antiandrogen was used in both RTOG 94-13 trial and the present study. Although a large-scale meta-analysis demonstrated that castration combined with non-steroidal antiandrogen was able to obtain significantly better survival than castration alone, the difference in survival was minimal. Therefore, when combined with radiotherapy for high-risk patients after radical prostatectomy, it is uncertain whether total androgen blockade would yield better outcome than castration alone.

Upon decision making for high-risk patients after radical prostatectomy, it is important to balance the expected efficacy and the possible adverse events. High-dose WPRT after radical prostatectomy could cause severe adverse events compared with PBRT. Although the authors did not investigate the adverse events in the present series, the difference in the profile of adverse events between WPRT and PBRT should be carefully evaluated.

Finally, in the present study, the radiation dose and technique (four-field or IMRT) were not constant over a long time-period of 20 years. Since this is a retrospective observational study, a well-designed randomized clinical trial is required to confirm the results of the present study.

Written by

Koichiro Akakura, MD, PhD - Department of Urology, Tokyo Kosei Nenkin Hospital, as part of Beyond the Abstract on UroToday.com. This initiative offers a method of publishing for the professional urology community. Authors are given an opportunity to expand on the circumstances, limitations etc... of their research by referencing the published abstract.

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