How accurate is our clinical prediction of "minimal prostate cancer"?
BACKGROUND
Recommendations for active surveillance versus immediate treatment for low risk prostate cancer are based on biopsy and clinical data, assuming that a low volume of well-differentiated carcinoma will be associated with a low progression risk. However, the accuracy of clinical prediction of minimal prostate cancer (MPC) is unclear.


OBJECTIVE
To define preoperative predictors for MPC in prostatectomy specimens and to examine the accuracy of such prediction.


METHODS
Data collected on 1526 consecutive radical prostatectomy patients operated in a single center between 2003 and 2008 included: age, body mass index, preoperative prostate-specific antigen level, biopsy Gleason score, clinical stage, percentage of positive biopsy cores, and maximal core length (MCL) involvement. MPC was defined as < 5% of prostate volume involvement with organ-confined Gleason score < or = 6. Univariate and multivariate logistic regression analyses were used to define independent predictors of minimal disease. Classification and Regression Tree (CART) analysis was used to define cutoff values for the predictors and measure the accuracy of prediction.


RESULTS
MPC was found in 241 patients (15.8%). Clinical stage, biopsy Gleason's score, percent of positive biopsy cores, and maximal involved core length were associated with minimal disease (OR 0.42, 0.1, 0.92, and 0.9, respectively). Independent predictors of MPC included: biopsy Gleason score, percent of positive cores and MCL (OR 0.21, 095 and 0.95, respectively). CART showed that when the MCL exceeded 11.5%, the likelihood of MPC was 3.8%. Conversely, when applying the most favorable preoperative conditions (Gleason < or = 6, < 20% positive cores, MCL < or = 11.5%) the chance of minimal disease was 41%.


CONCLUSIONS
Biopsy Gleason score, the percent of positive cores and MCL are independently associated with MPC. While preoperative prediction of significant prostate cancer was accurate, clinical prediction of MPC was incorrect 59% of the time. Caution is necessary when implementing clinical data as selection criteria for active surveillance.
Department of Urology, Assaf Harofeh Medical Center, Zerifin, affiliated with Sackler Faculty of Medicine, Tel Aviv University, Ramat Aviv, Israel. leibovicid@asaf.health.gov.il
Dan
D
Leibovici
Sergey
S
Shikanov
Ofer N
ON
Gofrit
Gregory P
GP
Zagaja
Yaniv
Y
Shilo
Arieh L
AL
Shalhav
D000328:Adult; D000367:Age Factors; D000368:Aged; D062005:Biopsy, Large-Core Needle / Q000379:methods / Q000706:statistics & numerical data; D015992:Body Mass Index; D002277:Carcinoma / Q000473:pathology / Q000601:surgery; D003951:Diagnostic Errors / Q000517:prevention & control*; D006801:Humans; D016013:Likelihood Functions; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D011237:Predictive Value of Tests; D011300:Preoperative Care / Q000379:methods* / Q000592:standards; D017430:Prostate-Specific Antigen / Q000097:blood; D011468:Prostatectomy / Q000379:methods*; D011471:Prostatic Neoplasms / Q000097:blood / Q000473:pathology / Q000601:surgery; D012044:Regression Analysis; D013048:Specimen Handling / Q000379:methods / Q000592:standards
D017430:Prostate-Specific Antigen