Calculated prostate cancer volume greater than 4.0 cm³ identifies patients with localized prostate cancer who have a poor prognosis following radical prostatectomy or external-beam radiation therapy

Purpose: Patients with palpable extraprostatic disease (T₃) have a poor prostate-specific antigen (PSA) failure-free (bNED) survival rate after radical prostatectomy (RP) or external-beam radiation therapy (RT). This study was performed to validate or refute the prognostic value of the previously defined calculated prostate cancer volume (cV(Ca)). Patients and Methods: For patients with clinically localized disease (T(1c,2)), a Cox regression multivariable analysis was used to assess the ability of the cV(Ca) value to predict time to posttherapy PSA failure following RP or RT. Results: The cV(Ca) value was a significant predictor (P ≤ .0005) of time to posttherapy PSA failure in both an RP and RT data set independent of the one used to derive the cV(Ca)-based clinical staging system. In both RP- and RT- managed patients, estimates of 3-year bNED survival were not statistically different for patients with either T(1c,2) disease and a cV(Ca) greater than 4.0 cm³ (RP, 27%; RT, 18%) or T₃ disease (RP, 37%; RT, 34%). Despite pathologic T₂ disease, the 3-year estimate of bNED survival was at most 51% in RP-managed patients with T(1c,2) disease and cV(Ca) greater than 4.0 cm³. Conclusion: A cV(Ca) greater than 4.0 cm³ identified patients with T(1c,2) disease whose bNED survival was poor after RT or RP despite pathologic T₂ disease that suggests the presence of occult micrometastatic disease in many of these patients. Prospective randomized trials to evaluate the impact on survival of adjuvant systemic therapy in these high-risk patients are justified.