Beyond D’Amico risk classes for predicting recurrence after external beam radiotherapy for prostate cancer: the Candiolo classifier

Abstract

BackgroundThe aim of this work is to develop an algorithm to predict recurrence in prostate cancer patients treated with radical radiotherapy, getting up to a prognostic power higher than traditional D’Amico risk classification.MethodsTwo thousand four hundred ninety-three men belonging to the EUREKA-2 retrospective multi-centric database on prostate cancer and treated with external-beam radiotherapy as primary treatment comprised the study population. A Cox regression time to PSA failure analysis was performed in univariate and multivariate settings, evaluating the predictive ability of age, pre-treatment PSA, clinical-radiological staging, Gleason score and percentage of positive cores at biopsy (%PC). The accuracy of this model was checked with bootstrapping statistics. Subgroups for all the variables’ combinations were combined to classify patients into five different “Candiolo” risk-classes for biochemical Progression Free Survival (bPFS); thereafter, they were also applied to clinical PFS (cPFS), systemic PFS (sPFS) and Prostate Cancer Specific Survival (PCSS), and compared to D’Amico risk grouping performances.ResultsThe Candiolo classifier splits patients in 5 risk-groups with the following 10-years bPFS, cPFS, sPFS and PCSS: for very-low-risk 90 %, 94 %, 100 % and 100 %; for low-risk 74 %, 88 %, 94 % and 98 %; for intermediate-risk 60 %, 82 %, 91 % and 92 %; for high-risk 43 %, 55 %, 80 % and 89 % and for very-high-risk 14 %, 38 %, 56 % and 70 %. Our classifier outperforms D’Amico risk classes for all the end-points evaluated, with concordance indexes of 71.5 %, 75.5 %, 80 % and 80.5 % versus 63 %, 65.5 %, 69.5 % and 69 %, respectively.ConclusionsOur classification tool, combining five clinical and easily available parameters, seems to better stratify patients in predicting prostate cancer recurrence after radiotherapy compared to the traditional D’Amico risk classes.Electronic supplementary materialThe online version of this article (doi:10.1186/s13014-016-0599-5) contains supplementary material, which is available to authorized users.

Increased EZH2 expression in prostate cancer is associated with metastatic recurrence following external beam radiotherapy

“…While the 10‐year BCR‐free survival was low at 22% for patients within this cohort, this is comparable with reported rates of 30% for high‐risk disease following external beam RT, and it is possible that BCR at such a mature length of follow‐up does not equate to true disease recurrence. While it is a strength of our study that the cohort was mature with a median follow‐up of 7.9 (IQR, 6.8‐8.4) years, we acknowledge that these were not consecutive patients from our institution due to inherent constraints acquiring archival tissue with retrospective follow‐up.…”

Unification of favourable intermediate‐, unfavourable intermediate‐, and very high‐risk stratification criteria for prostate cancer

“…Additionally, our present system unifies and simplifies several proposed modifications to the IR and HR NCCN groups. Lastly, other classification systems, such as the Candiolo classifier, have reported higher concordance indices than ours . However, they tend to be much more complicated than our present system, potentially overfitting their proposed models to their own datasets and precluding simple applicability in the clinic.…”

The Prostate Clinical Outlook (PCO) Classifier Application for Predicting Biochemical Recurrences in Patients Treated by Stereotactic Body Radiation Therapy (SBRT)

“…Based on the Kattan nomogram definition, the reported 5-year BCR-free survival rate was 95% for low risk, 90% for the intermediate risk, and 80% for high risk [27]. Our 5-year BCR-free survival rates are specific for prostate cancer patients treated with SBRT, while the others include patients treated with radical prostatectomy, external beam radiation therapy, and interstitial radiation therapy [9][10][11][12].…”

“…Risk assessments tools have been developed for predicting surgical and radiation therapy outcomes following standard prostate cancer treatment (i.e., D'Amico [9], Kattan nomogram [10], the University of California, San Francisco Cancer of the Prostate Risk Assessment (CAPRA) score [11], and the Candiolo classifier [12]). Although these risk assessments have been developed for predicting outcomes, these assessments have not been applied for use in patients treated with SBRT.…”