prostate cancer managed by active surveillance: a nomogram predicting the risk of biopsy progression. Viacheslav Iremashvili, Joshua Burdick-Will and Mark S.
Improving risk stratification in patients with prostate cancer managed by active surveillance: a nomogram predicting the risk of biopsy progression Viacheslav Iremashvili, Joshua Burdick-Will and Mark S. Soloway Department of Urology, Miller School of Medicine, University of Miami, Miami, FL, USA
Objective • To develop a clinical tool that integrates different risk factors and provides individual predictions of the risk of biopsy progression in patients with prostate cancer managed by active surveillance.
Materials and Methods • Our analysis included 205 patients on active surveillance, each of whom had had at least two surveillance biopsies. • We used the Cox proportional hazard regression model to analyse the association between different risk factors and progression-free survival over successive biopsies. This multivariate model was then used to develop a nomogram. • Discrimination and calibration of the nomogram were internally validated using 200 bootstrap resamplings.
Results • The median follow-up of patients free of progression was 4.6 years. A total of 58 (28%) patients experienced progression. • Factors significantly associated with progression were: overall number of positive cores in the diagnostic and
Introduction Active surveillance is a management strategy that aims to delay and possibly avoid prostate cancer treatments and their associated morbidity in closely monitored patients with low-risk prostate cancer. In recent years this strategy has gained increased acceptance and, according to most contemporary criteria, active surveillance is indicated in patients with low grade (Gleason 6), low-volume disease on biopsy, although the volume threshold varies somewhat between different protocols [1]. Prostate cancer in such patients has been deemed not to pose any threat to the patient’s survival in the mid-term and therefore does not
first surveillance biopsies, race and prostate-specific antigen density. • The bootstrapping concordance index of the nomogram including these variables was 81%. • The nomogram tended to underestimate the probability of progression but it identified fairly accurately the distinct groups of patients at low, intermediate and high risk of progression.
Conclusions • In the development cohort, the nomogram was able to separate patients with respect to their risk of biopsy progression. • Since accurate risk stratification is essential to optimize patient care, this tool, if external validation confirms its performance, may prove useful for both the counselling and management of patients with low-volume, Gleason 6 prostate cancer.
Keywords active surveillance, nomogram, prostate biopsy, prostate cancer, PSA density
require immediate treatment. Nevertheless, the population of patients eligible for active surveillance is far from homogeneous; some of them are found to have more extensive disease or a higher grade on repeat biopsy which suggests treatment is required [2–5]. Although it is not entirely clear whether this ‘progression’ is the result of changes in tumour biology (i.e. true progression) or simply represents more accurate sampling (i.e. reclassification), this is an undesired outcome, so to improve the results of active surveillance there is a need for prediction models that allow physicians to accurately identify patients with a greater risk of progression. Such tools would also allow doctors to provide those patients with low-risk prostate cancer more
© 2013 BJU International | 112, 39–44 | doi:10.1111/bju.12112
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Iremashvili et al.
Material and Methods As of November 2012, 336 men with prostate cancer were enrolled in our active surveillance programme and entered in a prospectively maintained institutional review board-approved database. Our inclusion criteria were as follows: biopsy Gleason sum
