Recursive partitioning for prognostic grouping of patients with clinicallylocalized prostate carcinoma

BACKGROUND. Patients treated with radical prostatectomy for clinically loca lized prostate carcinoma present considerable heterogeneity in terms of dis ease free survival outcome. Multiple studies have attempted to create progn ostic groupings of these patients in the perioperative phase, using informa tion available regarding several clinicopathologic variables. Such grouping s allow physicians to make early yet prudent decisions regarding adjuvant c ombination therapies. The current study presents results from a statistical analysis that enables the natural identification of such prognostic groups . METHODS. Examination of consecutive radical prostatectomy specimens was per formed between January 1991 and December 1995 at Wayne State University, Ha rper Hospital, Detroit, Michigan. Disease free survival in a cohort of 485 of these men was analyzed using recursive partitioning and amalgamation tec hnique. Clinicopathologic parameters evaluated included age, race, preopera tive prostate specific antigen (PSA) level, clinical and pathologic stage, and Gleason grade of the fine-needle biopsy as well as the radical prostate ctomy specimen. RESULTS. A binary decision tree representation was generated fur classifyin g patients based on the clinicopathologic variables mentioned earlier. The worst prognosis was for patients with either advanced stage and a PSA level > 24.1 ng/mL or advanced stage, a PSA level less than or equal to 24.1 ng/ mL, and age less than or equal to 65 years. This group had an estimated med ian disease free survival of only 10.3 months. Patients with lower patholog ic stage, prostatectomy Gleason scores of less than or equal to 7, and a pr eoperative PSA level less than or equal to 22.7 ng/mL had the best prognosi s. CONCLUSIONS. The recursive partitioning analyses allows easy characterizati on of a patient for prognosis shortly after radical prostatectomy, This wil l enable a physician to make more prudent decisions regarding whether to em ploy watchful waiting, proceed with accepted adjuvant therapy (radiotherapy or hormonal therapy), or refer patients to a research center that is able to administer experimental adjuvant therapy. (C) 2000 American Cancer Socie ty.