THE DEFINITION AND PREOPERATIVE PREDICTION OF CLINICALLY INSIGNIFICANT PROSTATE-CANCER

Objectives. - To define clinically insignificant prostate cancer accor ding to cancer volume, grade, cancer doubling time, and life expectanc y; and to determine how many insignificant cancers are removed by radi cal prostatectomy. Design and Patients. - Clinically insignificant can cer was defined as a tumor that would give rise to no more than 20 cm( 3) of cancer within the prostate by the time of expected patient death (1990 life tables) and whose Gleason score was less than 4 in 40- to 49-year-olds, 5 in 50- to 59-year-olds, 6 in 60- to 69-year-olds, and 7 in 70- to 79-year-olds. Four definitions were formulated based on as sumed cancer volume doubling times of 2, 3, 4, and 6 years. Using thes e four definitions, we reviewed 337 totally embedded prostates removed at Mayo Clinic between 1991 and 1993 for clinical stage T1c through T 3 cancer to determine how many contained clinically insignificant canc er. Main Outcome Measures. - Clinically significant vs clinically insi gnificant prostate cancer. Results. - For cancer volume doubling time of 2, 3, 4, and 6 years, clinically insignificant cancer was identifie d in one (0.3%), 13 (3.9%), 25 (7.4%), and 49 (14.5%) of 337 prostatec tomy specimens, respectively. Conclusions. - Clinically insignificant prostate cancer can be defined by cancer volume, grade, cancer volume doubling time, and life expectancy of the patient. According to our de finitions, most men treated with radical prostatectomy have clinically significant cancer.