Significant upgrading affects a third of men diagnosed with prostate cancer: predictive nomogram and internal validation

Authors


  • FKHC and AB contributed equally to the manuscript

Pierre I. Karakiewicz, Cancer Prognostics and Health Outcomes Unit, University of Montreal Health Center (CHUM), 1058, rue St-Denis, Montréal, Québec, Canada, H2X 3J4. e-mail: pierre.karakiewicz@umontreal.ca

Abstract

OBJECTIVE

To explore the rate of significant upgrading from biopsy to radical prostatectomy (RP) specimens in a contemporary cohort, and to develop a prognostic model capable of predicting the probability of significant upgrading, as previous reports indicate that up to 43% of men with low-grade prostate cancer at biopsy will be diagnosed with high-grade cancer at RP.

PATIENTS AND METHODS

The study cohort comprised 4789 men (median age 63 years, range 39–82) treated with RP, with available clinical stage, prostate-specific antigen levels, biopsy and RP Gleason sum values. These variables were used as predictors in multivariate logistic regression models (LRMs) addressing the rate of significant Gleason sum upgrading, defined as a Gleason sum increase either from ≤ 6 to ≥ 7 or from 7 to ≥ 8 between the biopsy and RP specimens. Regression coefficients were used to develop and validate (200 bootstrap re-samples) a nomogram predicting significant biopsy Gleason sum upgrading.

RESULTS

Significant biopsy Gleason sum upgrading was recorded in 1349 (28.2%) patients. In multivariate LRMs, all predictors were highly significant (all P < 0.001). The bootstrap-corrected accuracy of the nomogram predicting the probability of significant Gleason sum upgrading between biopsy and RP specimens was 75.7%.

CONCLUSION

Our nomogram might prove highly useful when the possibility of a more aggressive Gleason variant could change the treatment options.

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