ASCO 2017: Development and external validation of a novel risk score to identify insignificant prostate cancer

Chicago, IL ( Dr. Lorenzo Dutto and colleagues presented their work on developing a novel risk score to identify insignificant prostate cancer at the prostate cancer poster sessions at the 2017 ASCO Annual meeting in Chicago. Active surveillance (AS) is increasingly being used for monitoring men with low grade disease that is unlikely to be life-threatening. The objective of the current study was to evaluate the accuracy of nine separate tools to identify patients harboring insignificant prostate cancer using a novel risk score.

In this study, 2,799 patients who would have been candidates for AS (Gleason score 6 only) underwent robotic radical prostatectomy between 2006 and 2016 at a tertiary referral center. Insignificant prostate cancer was defined as Gleason 3+3 only, index tumour volume <1.3 cm3, and total tumor volume <2.5 cm3 (updated ERSPC definition). The authors computed the accuracy (specificity, sensitivity and area under the curve (AUC) of the receiver operator characteristic) of 9 predictive tools. This tool was validated in an external cohort of 441 unscreened patients undergoing surgery for Gleason 6 prostate cancer. All of the predefined tools rated poorly as predictors of insignificant disease as none of them reached the required AUC threshold of 0.7. The new tool performed well in training (AUC 0.76, 95%CI 0.74-0.77) and validation (AUC 0.76, 95%CI 0.70-0.82) cohorts. The weaknesses of this study include the retrospective nature, particularly an inherent selection bias since this is purely a radical prostatectomy cohort.

The authors concluded that pre-existing predictive tools to identify indolent prostate cancer have a poor predictive value when applied to an unscreened cohort of patients. This novel tool shows appropriate predictive power for insignificant prostate cancer in this population with training and validation cohorts. Prospective validation is required prior to widespread adoption of this risk score calculator. 

Presented By: Lorenzo Dutto, Klinik für Urologie, Kinderurologie und Urologische Onkologie, Prostatazentrum Nordwest, St. Antonius-Hospital, Gronau, Germany

Co-Author(s): Jorn H. Witt, Katarina Urbanova, Christian Wagner, Andreas Schuette, Mustafa Addali, John D Kelly, Senthil Nathan, Timothy Philip Briggs, Ashwin Sridhar, Stefania Gori, Amar Ahmad, Gregory Shaw

Written By: Zachary Klaassen, MD, Urologic Oncology Fellow, University of Toronto, Princess Margaret Cancer Centre, Toronto, Ontario, Canada
Twitter: @zklaassen_md

at the 2017 ASCO Annual Meeting - June 2 - 6, 2017 - Chicago, Illinois, USA

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