CLASSIFICATION OF LOCALIZED UNTREATED PROSTATE CANCER BASED ON 791 MEN TREATED ONLY WITH RADICAL PROSTATECTOMY: COMMON GROUND FOR THERAPEUTIC TRIALS AND TNM SUBGROUPS

Abstract

Purpose We examined cancer volume, percent Gleason grade 4/5 cancer, cancer location (peripheral versus transition zone), capsular penetration and biochemical cure rates in men undergoing radical prostatectomy to determine differences among clinical stages T1c, T2a, T2b and T2c. Materials and Methods Detailed chart reviews confirmed the precise clinical stages assigned to 791 consecutive men treated only with radical prostatectomy. All prostates were examined prospectively by the Stanford technique of 3 mm. step sections. For biochemical cure rates a subset of 366 men were followed for a minimum of 5 years. Failure was defined as prostate specific antigen Tosoh [dagger] 0.07 ng./ml. or greater and rising. T1c was defined as impalpable cancer. [dagger] TOSOH Medics, Foster City, California. Results T1c and T2a stages had half as much cancer volume as T2b and T2c cancers, 10 versus 25% Gleason grade 4/5 and half as much capsular penetration (30 versus 61%). Biochemical cure rates were 70 and 72% for T1c and T2a compared to 37 and 27% for T2b and T2c, respectively. Of T1c cancers 25% were in the transition zone compared to 7.9 to 9.9% of T2a to c cancers. Conclusions T1c cancers are similar to T2a cancers in tumor volume and percent Gleason grade 4/5, the primary determinants of therapeutic failure. Minimal 5-year cure rates for T1c and T2a cancers are similar. Transition zone cancers are 2.5 times more common in T1c cancers than in palpable T2 tumors. T2a cancers like T1c cancers are highly favorable tumors and should be retained in TNM classifications. These data suggest that the 4 clinical stages of T1c to T2c can serve as a valid basis for comparing different therapeutic strategies.