Greatest Percentage Involved Core Length and Risk of Clinically Significant Prostate-Specific Antigen Failure After Radical Prostatectomy. 
Radical prostatectomy (RP) can cure men with unfavorable intermediate- or high-risk prostate cancer (PC).  However, some will experience short prostate-specific antigen (PSA) doubling time (PSADT) failure that requires additional treatment with increased toxicity.  The present study investigated whether the greatest percentage of involved biopsy core length (GPC) can preoperatively identify men at risk of short PSADT failure.  A total of 503 men with biopsy-proven PC underwent RP at an academic institution from January 2005 to December 2008.  Men with incomplete pathologic information, those who had received neoadjuvant or adjuvant hormonal therapy or chemotherapy, and those who had undergone adjuvant radiation therapy were excluded.  The median follow-up period was 4.89 years (interquartile range, 1.97-5.68 years).  A competing risk regression was used to assess whether an increasing GPC value was associated with an increased PSADT at < 10-month failure risk, adjusting for age, percentage of positive biopsy results, and risk group.  Of the 402 men, 34 (8.46%) developed PSA failure, 17 (50.0%) of whom had a PSADT of < 10 months.  An increasing GPC value was significantly associated with an increased PSADT of < 10-month failure risk (adjusted hazard ratio, 1.03; 95% confidence interval, 1.01-1.06; P = .015).  Men with a GPC > 30% (median) versus ≤ 30% and unfavorable intermediate- or high-risk PC (P = .011), but not low or favorable intermediate-risk PC (P = .57), had a significantly greater incidence of PSADT < 10-month failure estimates (30% vs. 0% at 5 years).  Men planning to undergo RP for unfavorable intermediate- or high-risk PC with a GPC of > 30% should be considered for randomized trials evaluating the effect on survival of the neoadjuvant use of treatment that extends survival in those with castrate-resistant metastatic PC.