Does postoperative radiotherapy after radical prostatectomy improve progression-free survival in pT3N0 prostate cancer? (EORTC 22911)
Presenter: M. Bolla
Presenter's Affiliation: CHR de Grenoble, Grenoble, France
Type of Session: Scientific
A significant number of patients with clinical T1-2N0M0 prostate cancer are treated with radical prostatectmy. However, after pathologic evaluation, some patients are found to have risk factors for local failure. This trial designed by the EORTC evaluates postoperative external beam radiation treatment versus observation in patients with high risk pathological features following prostatectomy.Materials and Methods
- The EORTC undertook a mult-center, prospective, radomized study involving 1005 patients enrolled from late 1992 to 2001 in eight countries.
- Patients were no older than 75 years with WHO performance status of 0 or 1, preoperative staging of T0-3N0M0, and had at least one high risk pathological feature of capsular invasion, seminal vesicle invasion, or positive surgical margins.
- Patients were randomized to postoperative radiotherapy versus observation following radical retropubic prostatectomy. Patients were then stratified according to type of high risk pathological feature.
- Radiation consisted of conventional external beam treatment of 60 Gy over 6 weeks. 50 Gy was delivered to the pelvis and followed by 10 Gy to the surgical bed.
- The study was designed to detect a 7.5% increase in clinical or biological progression-free survival over 5 years. Secondary endpoints included overall survival, toxicity, and local control.
- The median age of all patients was 65.4 years with 94% having a PS of 0. Median pre- and post operative PSA values were 12.3 and 0.2, respectively.
- The trial was reviewed by the EORTC Idependent Data Monitoring Committee after a median follow-up period of 5 years in December 2003, and the committee recommended disclosure of early trial results.
- 8% of patients in the PORT group did not receive XRT, and 1% of patients in the observation group received XRT.
- Biochemical PFS at 5 years was significantly higher in the PORT group versus observation group (72.2% vs. 51.8%).
- Clinical PFS at 5 years was also significantly higher in the PORT group versus observation group (83.3% vs. 74.8%).
- The incidence of local recurrence at 5 years was significantly decreased in the PORT group versus observation group (5.2% vs. 15.2%).
- The PORT group demonstrated more immediate and delayed Grade 1 and 2 side effects with both groups having less than 5% Grade 3 side effects.
- Postoperative radiotherapy results in improved biochemical and clinical progression-free survival in patients with high risk pathological features following radical prostatectomy.
- The decision to treat must be balanced with concerns over side effects, as radiotherapy produces more Grade 1 and 2 early and late effects versus observation alone.
- It is too early to comment on overall survival, as there have been too few (<100) death events to this point to allow for adequate analysis.
The results of this trial promote the use of postoperative radiation treatment in patients with high risk pathological features following prostatectomy. Improved progression-free survival and decreased local recurrence must be balanced against the increased side effect profile. As with any prostate trial, 5 years is inadequate follow-up to make definitive conclusions about treatment efficacy, but these early results are encouraging. It will be interesting to observe the planned subanalysis as it applies to each high risk pathological feature used for stratification, as the clinical implications between the three may be very different.
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