Nomogram to predict insignificant prostate cancer at radical prostatectomy in Korean men: a multi-center study
Jae Seung Chung ; Han Yong Choi ; Young Deuk Choi ; Ho Song Yu ; Tae Young Jung ; Moon Kee Chung ; Wun-Jae Kim ; Tae-Kon Hwang ; Eun Sik Lee ; Hanjong Ahn ; Sang Eun Lee ; Jin Seon Cho ; Cheryn Song ; Seong Il Seo ; Seok-Soo Byun ; Hae-Ryoung Song
Yonsei Medical Journal, Vol.52(1) : 74~80, 2011
Yonsei Medical Journal
PURPOSE: Due to the availability of serum prostate specific antigen (PSA) testing, the detection rate of insignificant prostate cancer (IPC) is increasing. To ensure better treatment decisions, we developed a nomogram to predict the probability of IPC.
MATERIALS AND METHODS: The study population consisted of 1,471 patients who were treated at multiple institutions by radical prostatectomy without neoadjuvant therapy from 1995 to 2008. We obtained nonrandom samples of n = 1,031 for nomogram development, leaving n = 440 for nomogram validation. IPC was defined as pathologic organ-confined disease and a tumor volume of 0.5 cc or less without Gleason grade 4 or 5. Multivariate logistic regression model (MLRM) coefficients were used to construct a nomogram to predict IPC from five variables, including serum prostate specific antigen, clinical stage, biopsy Gleason score, positive cores ratio and maximum % of tumor in any core. The performance characteristics were internally validated from 200 bootstrap resamples to reduce overfit bias. External validation was also performed in another cohort.
RESULTS: Overall, 67 (6.5%) patients had a so-called "insignificant" tumor in nomogram development cohort. PSA, clinical stage, biopsy Gleason score, positive core ratio and maximum % of biopsy tumor represented significant predictors of the presence of IPC. The resulting nomogram had excellent discrimination accuracy, with a bootstrapped concordance index of 0.827.
CONCLUSION: Our current nomogram provides sufficiently accurate information in clinical practice that may be useful to patients and clinicians when various treatment options for screen-detected prostate cancer are considered