RTOG 94-06: Is the addition of neoadjuvant hormonal therapy to dose-escalated 3D conformal radiation therapy for prostate cancer associated with treatment toxicity?

Richard K. Valicenti, Kathryn Winter, James D. Cox, Howard M. Sandler, Walter Bosch, Srinivasan Vijayakumar, Jeff Michalski, James Purdy

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Purpose: This study determines the effect on toxicity of adding neoadjuvant hormonal therapy (NHT) to three-dimensional conformal radiation therapy (3D-CRT) in RTOG 94-06. Methods: Between August 1994 and February 2000, 583 eligible prostate cancer patients enrolled on the first 3 dose levels of RTOG 94-06, a Phase I/II dose escalation 3D-CRT trial. Two hundred and seven men initiated hormonal therapy (HT) between 2 to 3 months before 3D-CRT, and completed all HT no longer than 3 months after radiotherapy. Thirty-three patients receiving longer-duration HT were excluded. The 547 patients were treated at dose level I (68.4 Gy), level II (73.8 Gy), or level III (79.2 Gy). All dose prescriptions were to the minimum isodose surface encompassing the planning target volume (dose levels I and II) or the clinical target volume (dose level III). Men were stratified into three risk groups according to their relative risk of seminal vesicle invasion: <15% (Group 1) vs. >15% (Group 2), or to T stage (T1, 2 vs. T3 tumors [Group 3]). In Group 2 patients, there was a clinical target volume reduction to treat only the prostate after delivery of 55.8 Gy to a planning target volume including the seminal vesicles. All HT consisted of a luteinizing hormone-releasing hormone agonist with or without a nonsteroidal anti-androgen. Results: On univariate analysis, NHT significantly increased the likelihood of Grade 2 acute genitourinary (GU) complications (22% to 32%, p = 0.009). Hormonal therapy did not have a significant univariate effect on any other acute or late toxicity. On multivariate analysis, the percent of the bladder (≤30% vs. >30%) receiving ≥ the reference dose (68.4 Gy, 73.8 Gy, or 79.2 Gy) (p = 0.0009, relative risk = 2.07, confidence interval: 1.88-2.28) was a significant predictor of acute GU effects. Although NHT was not significant in itself, in the multivariate analysis its interaction with baseline urinary status was an important factor (p = 0.011, relative risk = 4.31, confidence interval: 1.68-5.29). Conclusion: Neoadjuvant HT did not show an independent effect on the risk of side effects after 3D-CRT in patients treated on RTOG 94-06. However, this combined modality therapy significantly increased the risk of acute GU effects compared to 3D-CRT alone in men with poor baseline urinary function.

Original languageEnglish
Pages (from-to)614-620
Number of pages7
JournalInternational Journal of Radiation Oncology Biology Physics
Issue number3
StatePublished - Nov 1 2003


  • 3D conformal radiation therapy
  • Hormonal therapy
  • Prostate cancer
  • Toxicity


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