Does Pelvis and Prostate Radiation Therapy Compared to Prostate Radiation Therapy Alone Improve Survival in Patients with Non Metastatic Prostate Carcinoma? Preliminary Results of the Prospective Randomized GETUG 01 Trial

English

Reviewer: Chika Madu, MD
Abramson Cancer Center of the University of Pennsylvania
Ultima Vez Modificado: 18 de octubre del 2005

Presenter: P. Pommier
Presenter's Affiliation: Centre Leon Berard, Lyon, France
Type of Session: Scientific

Background

There has been ongoing controversy regarding the role of whole pelvis radiotherapy in patients with non-metastatic prostate cancer. The goal of this multicenter study was to evaluate the progression free survival (PFS) between pelvis and prostate RT (WP) vs. prostate only RT (PO) in patients with non-metastatic prostate cancer

Materials and Methods

Between 12/98-06/04, 444 patients with a median age of 70 (range 50-75) were accrued
Patients had T1b, T2 or T3 N0 M0 prostate cancer without distant metastasis, and a karnofsky index >70%
All patients randomized to pelvis and prostate RT(group A), or prostate RT only (group B)
Patients were stratified according to prognostic factors: low, intermediate, and high risk
Radiation therapy was 46Gy in 2Gy fractions to the pelvic field, the prostate was boosted to 66Gy in all patients treated before March 2000, and 70Gy in patients treated after March, 2000.
Radiation techniques were 3-D conformal, 4-8 fields
Short term hormonal therapy (STHT) for 6-months was allowed for group B patients
Biological PSA recurrences according to RTOG was used as progression criteria
450 patients were needed to see a 15% improvement in PFS at 5 years
Analysis was based on intent-to-treat
PFS was defined as the interval between enrollment and death, progression, or loss to follow-up
Quality of life assessment, acute and late toxicities were also evaluated
Kaplan-Meier, Log Rank test, and the Cox model were used for statistical analysis

Results

80% of patients were stratified as intermediate or high risk tumors.
Median dose to the prostate was 68.4Gy (65-74Gy) in both groups. 2 patients stopped radiation after 4Gy and 22Gy
At 3.3year median follow up, there was no difference in progression rates between groups A or B: 18% vs. 17%
There was no difference in 5-year PFS between group A and B (67.8% vs. 63.6%) respectively.
5-year OS rates were 88% for group A and 86.8% for group B with no statistical significance
Acute grade 2-4 rectal toxicity was 30.6% vs. 24.25 in group A and group B respectively
There was no difference in quality of life in both groups

Author's Conclusions

Whole pelvic radiation was well tolerated in this study
However, there was no difference in survival with the use of whole pelvis irradiation

Clinical/Scientific Implications

Some may compare this study to the RTOG 9413 study which showed a PFS benefit in 2003 for patients treated with neo-adjuvant hormonal therapy and whole pelvis radiation. However, the studies are different in several ways. The doses were slightly lower in this study and several patients had favorable prognosis and may not benefit from whole pelvis radiation. The preliminary results of this study indicate that there is no benefit to whole pelvis radiation but this study may have been underpowered to show an impact of STHT. This study certainly does not disprove RTOG 9413. Of note is that a recent update of RTOG 9413 has shown that the results have degraded. The follow up is very short in this study and at least 5 yr follow-up is needed to make any initial conclusions. The question remains as to whether treatment of the whole pelvis is worth the slight PFS benefit shown in RTOG 9413.