OBJECTIVE: To establish an external validation of the updated nomogram from Briganti et al, which provides estimates of the probability of specimen-confined disease from age, PSA, clinical stage, and biopsy Gleason score in preoperatively defined high risk PCa.
PATIENTS AND METHODS: 523 high-risk PCa patients as defined by d'Amico classification undergoing RP and bilateral lymph node dissection in two academic centres between 1990 and 2013. Specimen-confined (SC) disease was defined as pT2-pT3a node-negative PCa with negative surgical margins. The Receiver Operating Characteristic (ROC) curve was obtained to quantify the overall accuracy (Area Under the Curve, AUC) of the model to predict SC disease. Calibration curve was then constructed to illustrate the relationship between the risk-estimates obtained by the model (X-axis) and the observed proportion of SC disease (y-axis). Kaplan-Meier method was used for biochemical recurrence-free survival (BCR) assessment.
RESULTS: Median age and PSA level were 64 years and 21 ng/ml. Definition of high risk PCa was based on PSA level only in 38.3% of cases, a biopsy Gleason score >7 in 34.5% of cases, a clinical stage >T2b in 6.9% of cases, or a combination of these 2 or 3 factors in 20.3% of cases. Positive surgical margins were observed in 43.6% with a rate of 14.8% in pT2 cancers, lymph node metastasis in 12.1% patients. pT stage was pT0:0.9%, pT2:28.9%, pT3a:37.5%, and pT3b-4:32.7%. Overall, 44.4% of PCa had (n=232) SC disease. PSA, and cT were independently predictive for SC disease. The 2-, 5-, and 8-year BCR free recurrence was significantly improved in specimen-confined disease as compared with not organ-confined disease (respectively 80.87% [73.67; 86.29] vs 37.55% [30.64; 44.44]; 63.53% [52.37; 72.74] vs 26.93% [19.97; 34.36]; 55.08 % [41.49; 66.74] vs 19.52% [12.50; 27.70]; p< 0.0001). ROC curve analysis showed relevant accuracy of the model (AUC: 0.6470 (95%CI=[0.60-0.69])) although the calibration plot suggested that, for risks ranging from 0.3 and 0.5, the odds of extracapsular extension were underestimated.
CONCLUSIONS: This external validation of the Briganti nomogram shows relevant accuracy although the relative imprecision for intermediate risks may limit its clinical relevance. Our follow-up findings confirm the large proportion of specimen-confined PCa with good oncologic outcomes in this heterogeneous subgroup of high risk PCa.
Written by:
Roumiguié M, Beauval JB, Filleron T, Benoit T, Rischmann P, de la Taille A, Salomon L, Soulié M, Malavaud B, Ploussard G. Are you the author?
Reference: BJU Int. 2014 Mar 31. Epub ahead of print.
doi: 10.1111/bju.12763
PubMed Abstract
PMID: 24684584
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