Baldi, Ileana

Delsedime, Luisa

Fiano, Valentina

Grasso, CHIARA CELESTINA

Maule, MILENA MARIA

Merletti, Franco

Richiardi, Lorenzo

Zugna, Daniela

English

Institutional Research Information System University of Turin

TIME-DEPENDENT PREDICTIVE ACCURACY OF PROSTATE CANCER  SPECIFIC MORTALITY OF THE CONTEMPORARY vs. ORIGINAL GLEASON SCOREMilena Maule1, Ileana Baldi2, Luisa Delsedime3, Chiara Grasso1, Valentina Fiano1, Daniela Zugna1, Franco Merletti1, Lorenzo Richiardi11 Cancer Epidemiology Unit, University of Turin, Italy2 Department of Environmental Medicine and Public Health, University of Padua, Italy3 Department of Pathology, San Giovanni Battista Hospital, Turin, Italycontact: milena.maule@cpo.itProstate cancer is the most frequent male cancer in the US and Western Europe.The Gleason score (GS) is the most important prognostic indicator. A gradual upgrading in GS has occurred from the early 1990s to the early 2000s. In 2005, the International Society of Urological Pathology issued a  revision of assignment criteria, causing a further upward shift of GS.A consequence of upgrading is an apparent but spurious improvement in grade-specific survival for more recent cases due to grade migration (Will Rogers phenomenon).Aim of the study: to assess, for the first time, the ability of the contemporary GS in predicting prostate cancer-specific mortality.Rationale and aimCohort of consecutive prostate cancer patients identified at a single pathology ward between 1993 and 1996. The GS assigned at diagnosis (“original GS”) extracted from the pathology report; diagnostic slides blindly re-evaluated in 2010 by an experienced uropathologist (L.D.) according to current criteria (“contemporary GS”).Patients followed-up until 15/01/2007 and death certificates obtained from the demographic offices.Effect of grade migration: assessed through cumulative probability of death from prostate cancer, taking into account competing risk events.Time-dependent measures for the accuracy of the original and contemporary GS in predicting the probability of prostate cancer death: ROC curves at different follow-up times, with censored survival and competing risks.AUCs compared through a Wilcoxon rank sum test for dependent samples.MethodsResultsApplication of the contemporary GS criteria entails the artefactual improvement in clinical outcomes known as the Will Rogers phenomenon. Contemporary GS does not improve prediction of prostate cancer-specific mortality at least for the first 5 years of follow up. GS has been the strongest prognostic factor for prostate cancer since its introduction, is included in all prognostic models for prostate cancer, and is a critical factor in deciding on the choice of treatment. Although we did not evaluate the ability of the original and the contemporary GS to indicate the appropriate treatment for prostate cancer, we found that the contemporary GS is worse rather than better in predicting prostate cancer mortality, at least in the shorter term. Discussion and conclusions Characteristics Patients  N % Patients 243  Person years 1591  Mortality   Overall 177     Due to prostate cancer 76 42.9    Due to other causes 101 57.1 Range follow-up time  (years)  0-14  Median survival time (years) 6.3 (IQR: 2.6-14) Mean age at diagnosis 70.6 (sd: 8.7) Source of tumor tissue   Biopsy 164 (sd: 67.5) TURP 45 18.5 Radical prostatectomy 34 14.0 Table 1. Characteristics of prostate cancer patients included in the cohort. Turin, 1993-1996 Contemporary Gleason score  (N) <7 7 8+ Original Gleason score (N) (68) (72) (91) <7 (131) 59 52 20 7 (32) 3 9 20 8+ (68) 6 11 51  Table 2. Distribution of original and contemporary GS.0.1.2.3.4.5Cumulative probability of prostate cancer death0 5 10 15Years since diagnosisOriginalContemporaryGleason score < 70.1.2.3.4.5Cumulative probability of prostate cancer death0 5 10 15Years since diagnosisOriginalContemporaryGleason score = 70.1.2.3.4.5Cumulative probability of prostate cancer death0 5 10 15Years since diagnosisOriginalContemporaryGleason score = 8+Figure 1. Cumulative probability of death due to prostate cancer by original and contemporary GS: the Will Rogers phenomenon.Area Under Curve Time since diagnosis Gleason score 1 year 5 years 10 years Original 0.77 (0.67-0.86) 0.70 (0.63-0.78) 0.71 (0.62-0.80) Contemporary  0.68 (0.56-0.78) 0.64 (0.56-0.72) 0.75 (0.68-0.82)  Figure 2. Time dependent predictive accuracy of original and contemporary GS (<7, 7, 8+) measured as the area under curve (AUC) of the receiver operating characteristics (ROC) curves at 1, 5 and 10 years after prostate cancer diagnosis.

TIME-DEPENDENT PREDICTIVE ACCURACY OF PROSTATE CANCER  SPECIFIC MORTALITY OF THE CONTEMPORARY vs. ORIGINAL GLEASON SCORE

https://iris.unito.it/bitstream/2318/1650633/1/Maule_sismec2011.pdf

TIME-DEPENDENT PREDICTIVE ACCURACY OF PROSTATE CANCER SPECIFIC MORTALITY OF THE CONTEMPORARY vs. ORIGINAL GLEASON SCORE

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