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The definition and preoperative prediction of clinically insignificant prostate cancer
J A Dugan1, D G Bostwick, R P Myers
1Department of Urology, Mayo Clinic, Rochester, Minn, USA.
Objectives:
To define clinically insignificant prostate cancer according to cancer volume, grade, cancer doubling time, and life expectancy; and to determine how many insignificant cancers are removed by radical prostatectomy.
Design And Patients:
Clinically insignificant cancer was defined as a tumor that would give rise to no more than 20 cm3 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 assumed cancer volume doubling times of 2, 3, 4, and 6 years. Using these four definitions, we reviewed 337 totally embedded prostates removed at Mayo Clinic between 1991 and 1993 for clinical stage T1c through T3 cancer to determine how many contained clinically insignificant cancer.
Main Outcome Measures:
Clinically significant vs clinically insignificant prostate cancer.
Results:
For cancer volume doubling time of 2, 3, 4, and 6 years, clinically insignificant cancer was identified in one (0.3%), 13 (3.9%), 25 (7.4%), and 49 (14.5%) of 337 prostatectomy 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 definitions, most men treated with radical prostatectomy have clinically significant cancer.