Phase III trial of androgen suppression adjuvant to definitive radiotherapy. Long term results of RTOG study 85-31.

Reviewer: Ryan Smith, MD
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Ultima Vez Modificado: 31 de mayo del 2003

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Presenter: M.V. Pilepich
Presenter's Affiliation: RTOG
Type of Session: Scientific

Background

  • RTOG 85-31 was one of the first studies investigating adjuvant androgen suppression in the treatment of prostate cancer.
  • Since the publication of this study, many others investigating the use of adjuvant hormones have been performed.
  • Though this was initially a positive study (with 5 years of follow-up), this is not enough follow-up to fully answer questions in prostate cancer.
  • This presentation updated the results of RTOG 85-31, to include 12 year results

Materials and Methods

  • Patients with T3/T4 or lymph node positive disease comprised the study group
  • Patients who had undergone radical prostatectomy who had extracapsular extension or seminal vesicle involvement were also eligible
  • Patients all received 46 Gy to the whole pelvis with a boost to the primary tumor to 65-70 Gy (post-surgical patients were treated to a dose of 60-65 Gy)
  • Patients were randomized between no additional therapy or the initiation of goserelin during the last week of radiation to be continued indefinitely or until signs of progression
  • Patients on the radiation therapy alone arm could receive goserelin if progression of disease was noted
  • 977 patients were entered on study, with median follow up of 7.3 years
  • 28% had positive lymph nodes, 15% were post-surgical

Results

  • Patients who received hormones did better in all parameters measured
  • Local failure was 23% vs. 39% (p<.0001)
  • Distant metastatic rate was 25% vs. 39% (p<.0001)
  • Biologic failure free survival was 30% vs. 9% (p<.0001)
  • Prostate cancer specific survival was much better in the group treated with hormones (exact data not given) (p=.0053)
  • Absolute survival was 53% vs 38% (p=.0043)
  • On subset analysis for absolute survival, in patients with Gleason score (GS) 2-6, there was a separation of the curves, though the differences were not significant. In patients with GS 7 disease, there was a significant difference (p=.042), and in patients with GS 8-10 disease, there was a large difference in survival (p=.006)

Author's Conclusions

  • Adjuvant hormonal therapy in patients with stage T3/4 and node positive prostate cancer provides a benefit in all endpoints analyzed
  • These trends not only held from the last paper, but actually increased over time
  • There is a profound effect in patients with the above parameters and GS 8-10 disease

Clinical/Scientific Implications

    The original presentation of this data was one of the first studies showing an advantage of adjuvant hormonal therapy. This update continues to show an advantage in this specific subset of patients-T3/4 tumors, lymph node positive disease, or patients who underwent radical prostatectomy with poor prognostic features at time of surgery. In fact, the most important endpoint, that of absolute survival, is now statistically significant in favor of the adjuvant androgen ablation arm, which was not seen in the original paper. Therefore, for this subset of patients, adjuvant androgen ablation should remain the standard of care. Data presented for the subset analyses (by Gleason score) should be interpreted with caution. Subset analyses are meant to be hypothesis generating, but the points brought out by the subset analyses in this presentation have already been tested and proven (adjuvant hormonal therapy is indicated in aggressive (high GS) disease and high PSA disease). Therefore, the use of these additional analyses is severly limited. Also, it should be kept in mind that androgen ablation is not without side effects, and this makes no comment on overall quality of life in these patients.

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