A nomogram to predict Gleason sum upgrading of clinically diagnosed localized prostate cancer among Chinese patients

Although several models have been developed to predict the probability of Gleason sum upgrading between biopsy and radical prostatectomy specimens, most of these models are restricted to prostate- specific antigen screening-detected prostate cancer. This study aimed to build a nomogram for the prediction of Gleason sum upgrading in clinically diagnosed prostate cancer. The study cohort comprised 269 Chinese prostate cancer patients who underwent prostate biopsy with a minimum of 10 cores and were subsequently treated with radical prostatectomy. Of all included patients, 220 （81.8%） were referred with clinical symptoms. The prostate-specific antigen level, primary and secondary biopsy Gleason scores, and clinical T category were used in a multivariate logistic regression model to predict the probability of Gleason sum upgrading. The developed nomogram was validated internally. Gleason sum upgrading was observed in 90 （33.5%） patients. Our nomogram showed a bootstrap-corrected concordance index of 0.789 and good calibration using 4 readily available variables. The nomogram also demonstrated satisfactory statistical performance for predicting significant upgrading. External validation of the nomogram published by Chun et aL in our cohort showed a marked discordance between the observed and predicted probabilities of Gleason sum upgrading. In summary, a new nomogram to predict Gleason sum upgrading in clinically diagnosed prostate cancer was developed, and it demonstrated good statistical performance upon internal validation.     

Validation of a nomogram to predict disease progression following salvage radiotherapy after radical prostatectomy: results from the SEARCH database

OBJECTIVE

To externally validate the nomogram published by Stephenson et al. (termed the ‘Stephenson nomogram’) to predict disease progression after salvage radiotherapy (SRT) among patients with prostate cancer from the Shared Equal Access Regional Cancer Hospital (SEARCH) database.

PATIENTS AND METHODS

We analysed data from 102 men treated with SRT for prostate‐specific antigen (PSA) failure after prostatectomy, of whom 30 (29%) developed disease progression after SRT during a median follow‐up of 50 months. The predicted 6‐year progression‐free survival (PFS) was compared to the actuarial PFS using calibration plots. The accuracy of the nomogram to risk‐stratify men for progression was assessed by the concordance index.

RESULTS

The median PSA and PSA doubling time before SRT was 0.6 ng/mL and 10.3 months, respectively. The 6‐year actuarial disease‐free progression after SRT was 57% (95% confidence interval 42–69%). The overall concordance index of the Stephenson nomogram was 0.65. The nomogram predicted failure more accurately at the extremes of risk (lowest and highest) but in intermediate groups, the accuracy was less precise. Of the 11 variables used in the nomogram, only negative margins and high PSA level before SRT were significantly associated with increased disease progression.

CONCLUSION

The Stephenson nomogram is an important tool to predict disease progression after SRT following radical prostatectomy. It adequately predicted progression in SEARCH with reasonable accuracy. Also, in SEARCH, disease progression was predicted by similar disease characteristics. However, the overall modest performance of the model in our validation cohort indicates there is still room for improvement in predictive models for disease progression after SRT.     

Continuous monitoring of micturition pattern in nonhuman primates: Similarities to humans

Most experimental urodynamic studies have been carried out in animals under anesthesia. This study is performed on awake, unrestrained, upright animal models phylogenetically similar to humans. Five female rhesus monkeys were monitored for their micturition pattern using the system described in Part I. The voiding frequency, physiologic diuresis, and the early voiding correspond well to those of humans. A peak flow nomogram was constructed based on 357 urinations. It depicts a non-linear relation of peak flow to increasing voided volume. The nomogram is similar in pattern to those developed for humans. These findings suggest that the rhesus monkey is one of the best animal models to study the function of lower urinary tract. © 1992 Wiley-Liss, Inc.     

Development and external validation of an extended repeat biopsy nomogram

PURPOSE: We hypothesized that the outcome of repeat biopsy could be accurately predicted. We tested this hypothesis in a contemporary cohort from 3 centers. MATERIALS AND METHODS: The principal cohort of 1,082 men from Hamburg, Germany was used for nomogram development as well as for internal 200 bootstrap validation in 721 and external validation in 361. Two additional external validation cohorts, including 87 men from Milan, Italy and 142 from Seattle, Washington, were also used. Predictors of prostate cancer on repeat biopsy were patient age, digital rectal examination, prostate specific antigen, percent free prostate specific antigen, number of previous negative biopsy sessions and sampling density. Multivariate logistic regression models were used to develop the nomograms. RESULTS: The mean number of previous negative biopsies was 1.5 (range 1 to 6) and the mean number of cores at final repeat biopsy was 11.1 (range 10 to 24). Of the men 370 (30.2%) had prostate cancer. On multivariate analyses all predictors were statistically significant (p < or =0.028). After internal validation the nomogram was 76% accurate. External validation showed 74% (Hamburg), 78% (Milan) and 68% (Seattle) accuracy. CONCLUSIONS: Relative to the previous nomograms (10 predictors or 71% accuracy) our tool relies on fewer variables (6) and shows superior accuracy in European men. Accuracy in American men is substantially lower. Racial, clinical and biochemical differences may explain the observed discrepancy in predictive accuracy.