Objectives. To evaluate whether the calculated volume of prostate cancer (cVca) in patients with clinical Stage T1c prostate cancer who were treated surgically was a good predictor of biochemical disease-free prostate-specific antigen (PSA] recurrence. Methods. Between 1990 and 1996, patients with prostate cancer who were surgically treated for clinical Stage Tie at Brigham and Women's Hospital were retrospectively evaluated, and 188 patients (median PSA 6.9 ng/mL) were included in this study. cVca (determined by cancer-specific PSA, prostate volume, and Gleason grade), pathologic stage, and time to PSA failure were assessed. Results. cVca correlated strongly with the preoperative PSA level (P <0.00001, chi-square test), Gleason grade (P <0.00001), and pathologic stage (P <0.00001). Kaplan-Meier curves for PSA disease-free survival were constructed for patients with cVca less than 0.5 cm(3) (group 1), cVca of 0.5 to 4.0 cm(3) (group 2), and cVca greater than 4.0 cm(3) (group 3). The 2-year PSA disease-free survival rate was 100%, 87%, and 36% for groups 1, 2, and 3, respectively (P <0.0001). Cox multiple regression analysis demonstrated that cVca was superior to PSA and Gleason score for determination of serologic PSA failure after surgery. Conclusions. Our results demonstrated that cVca is a good predictor of biochemical recurrence in patients with clinical Stage T1c prostate cancer. Perhaps, after validation by others, cVca can serve as a tool in choosing various treatment options for prostate cancer. UROLOGY 56: 273-277, 2000. (C) 2000, Elsevier Science Inc.