14651 Background: “Watchful waiting (WW)” is becoming a common treatment option for patients (pts) with screening detected prostate cancer. There is, however, no consensus about which pts are suitable for WW and how pts are monitored. Methods: Eligibility criteria: 1) stage T1c prostate cancer pts, 2) age 50–80, 3) serum PSA: 20 ng/ml or less, 4) 1 or 2 positive cores per 6 to 12 systematic core biopsies, 5) Gleason score of 6 or less, 6) 50% or less maximum % cancer occupation in a positive core. The criteria of 4), 5), 6) were confirmed by a central pathologist before pts registration. Registered patients chose either WW or immediate aggressive treatment. In patients who chose WW, serum PSA was monitored every 2 months for 6 months and PSA-doubling time (PSADT) was calculated centrally. Those who showed PSADT 2y and re-biopsy at 13 months fit the initial pathology criteria again. Primary endpoint was “% PSADT > 2 y”, which was defined as proportion of patients who showed PSADT at 6 months > 2 y out of all patients who chose WW. Point estimate of “% PSADT > 2 y” was expected to be higher than 80%. The planned sample size was 100 pts who chose WW, which gives the width of 95% confidence intervals for % PSADT > 2 y within 10%. Results: 134 pts were enrolled from 01/2002 to 12/2003 and 118 pts chose WW while 13 pts chose aggressive treatment (surgery, radiotherapy, hormonal therapy). The initial 6 months’ PSADT could be assessed in 106 patients (measurement point error in 6, early dropout in 6). Of 106 patients, 22 showed PSADT < 2 y (“rapid riser”) while 84 showed PSADT > 2 y. “% PSADT > 2 y” was 71.2% (84/118, 95% CI: 62.1–79.2%). 84 pts have continued WW with median follow-up of 27 months. Neither metastasis nor cancer-death was observed until 06/2005. As to health-related QOL, any domain of SF-36 was not impaired in patients who continued WW at least for 1 year. Conclusion: Our initial selection criteria for WW may include at least 20% of “rapid riser”, hence need further modification. Additionally, it should be confirmed by further follow-up of 84 pts whether eliminating “rapid riser” from WW by initial 6 months’ PSADT is appropriate. No significant financial relationships to disclose.
