Nomogram Ranking as New Objective Evaluation Method in Various Treatment Strategies for Patients With Prostate Cancer With Various Clinicopathologic Backgrounds

Abstract

To propose a "nomogram ranking" that gives an objective assessment of any treatment strategy from various institutions. It is difficult to objectively compare treatment outcomes for patients with prostate cancer among institutions because of the large differences in the clinicopathologic backgrounds and treatment strategies. From January 2001 to September 2005, 71 consecutive patients with locally advanced prostate cancer were treated with external beam radiotherapy (EBRT) and subsequent high-dose rate brachytherapy combined with long-term hormonal therapy. The 5-year prostate-specific antigen relapse-free survival (PFS) rates were calculated by Kaplan-Meier analysis for all patients and also for subdivided patients according to prostate-specific antigen range or Gleason score. Also, the 5-year PFS rates were estimated by Kattan nomogram, assuming that all 71 patients were treated with 72 Gy of EBRT or EBRT plus neoadjuvant hormonal therapy. The estimated PFS rates were ranked in order from worse to better outcomes (nomogram ranking). The 5-year PFS rates estimated by Kaplan-Meier analysis assessed the position within the nomogram ranking. The 5-year PFS rate estimated by Kaplan-Meier analysis for all 71 patients was 82.4%. The median 5-year PFS rate estimated by Kattan nomogram was 66%, assuming that all patients were treated with EBRT and neoadjuvant hormonal therapy. The actual 5-year PFS rate estimated by Kaplan-Meier analysis ranked 56 of 71 patients assumed to be treated with neoadjuvant hormonal therapy and EBRT. Subdivided analyses revealed that our treatment strategy might be advantageous for patients with a Gleason score of 7 or less, regardless of the prostate-specific antigen level. The nomogram ranking might be an objective and reliable assessment method of various treatment strategies for patients with prostate cancer.