The Outcome of Neoadjuvant Hormonal Therapy with Radiation Therapy Depends on the Definition of Biochemcial Failure

Abstract

Purpose: We compared biochemical control rates of 3D conformal radiation therapy (3DCRT) plus neoadjuvant hormonal therapy (NHT) with those of prostate 3DCRT alone. We also examined the effect that two definitions of biochemical failure had on the comparison. Patients and Methods: We studied 126 men with stage T1-3B prostate cancer, who were treated with 3DCRT (Median dose of 72.0 Gy prescribed to the PTV) to the prostate alone (minimum follow-up duration of 1 year). Thirty-nine men received 4 to 6 months of NHT and 87 had 3DCRT alone. Hormonal therapy consisted of a LHRH agonist +/- an anti-androgen. We subdivided the patients into risk categories according to their baseline PSA and Gleason score: Low risk (Gleason Scores >7 and baseline PSA >10), Intermediate risk (Gleason Scores >7 and baseline PSA ≥10 or Gleason Scores ≥7 and baseline PSA >10), and High risk (Gleason Scores ≥7 and baseline PSA ≥10). We used two definitions of biochemical failure. First we defined failure according to the American Society for Therapeutic Radiology and Oncology (ASTRO) consensus statement. In the second analysis, biochemical failure was defined as three serial rises in the PSA with a rise above 1.5 ng/ml. Results: According to the ASTRO definition, the use of neoadjuvant hormonal therapy resulted in a significantly lower PSA control rate in low and intermediate risk patients (P = .0028). When the data was reanalyzed using the second definition for PSA failure, the results were reversed, in that the biochemical outcomes of HT patients were better than the outcomes of patients who received 3DCRT alone. Conclusion: This reversal of outcome indicates that treatment outcome depends on definition of biochemical failure in patients receiving NHT. Given this limitation, it is important that ASTRO address the use of hormonal therapy in devising a new consensus statement defining biochemical failure.