Asians with Localized Prostate Cancer Treated with 3-Dimensional Conformal Radiation Therapy and Adjuvant Hormonal Therapy: Comparing Phoenix and American Society of Therapeutic Radiology and Oncology (ASTRO) Definitions in an Asian Population

Abstract

Conformal radiotherapy with adjuvant androgen suppression is used in our center to treat localized prostate cancer. We compare Phoenix as an alternative to American Society of Therapeutic Radiology and Oncology (ASTRO) for defining biochemical failure. Our primary aim was to assess the Phoenix and ASTRO definitions of biochemical failure in a population of mainly Asian men with early localized prostate cancer treated with conformal radiotherapy with and without androgen ablation. We retrospectively analyzed 141 patients who were treated for T1/T2 cancer of the prostate in our center from January 1997 to June 2002 with a mean duration of follow-up of 62 months. Outcomes were analyzed by using both Phoenix and ASTRO definitions of biochemical failure as well as clinical failure. The Phoenix definition of biochemical failure was superior as measured by sensitivity, specificity, positive and negative predictive values, accuracy, and a greater concordance with clinical outcome as measured by Kappa analysis. The ASTRO definition helped to standardize reporting of biochemical failures post-radiotherapy but inadequacies have been identified especially when adjuvant hormone therapy has been given. The Phoenix definition has been noted to be a more accurate and precise description of biochemical failure in international series, and we find this to be true in our Asian population as well.