PSA doubling time of prostate carcinoma managed with watchful observation alone

Purpose: To study prostate-specific antigen (PSA) doubling time of untreated, favorable grade, prostate carcinoma, Methods and Materials: A prospective single-arm cohort study has been in progress to assess the feasibility of a watchful observation protocol with selective delayed intervention using clinical, histologic, or PSA progression as treatment indication in untreated, localized, favorable grade prostate adenocarcinoma (T1b-T2bNO MO, Gleason Score less than or equal to 7, and PSA less than or equal to 15 ng/mL), Patients are conservatively managed with watchful observation alone, as long as they do not meet the arbitrarily defined disease progression criteria. Patients are followed regularly and undergo blood tests including PSA at each visit. PSA doubling time (Td) is estimated from a linear regression of In(PSA) on time, assuming a simple exponential growth model. Results: As of March 2000, 134 patients have been on the study for a minimum of 12 months (median, 24; range, 12-52) and have a median frequency of PSA measurement of 7 times (range, 3-15). Median age is 70 years. Median PSA at enrollment is 6.3 (range, 0.5-14,6), The distribution of Td is as follows: <2 years, 19 patients; 2-5 years, 46; 5-10 years, 25; 10-20 years, 11; 20-50 years, 6; > 50 years, 27, The median Td is 5.1 years. In 44 patients (33%), Td is greater than 10 years. There was no correlation between Td and patient age, clinical T stage, Gleason score, or initial PSA level. Conclusion: Td of untreated prostate cancer varies widely. In our cohort, 33% have Td > 10 years, Td may be a useful tool to guide treatment intervention for patients managed conservatively with watchful observation alone. (C) 2001 Elsevier Science Inc.