External validation of the Briganti nomogram to estimate the probability of specimen‐confined disease in patients with high‐risk prostate cancer

Abstract

ObjectiveTo establish an external validation of the updated nomogram from Briganti et al., which provides estimates of the probability of specimen-confined disease using the variables age, prostate-specific antigen (PSA), clinical stage and biopsy Gleason score in preoperatively defined high-risk prostate cancer (PCa). Patients and MethodsThe study included 523 patients with high-risk PCa, as defined by d'Amico classification, undergoing radical prostatectomy (RP) and bilateral lymph node dissection in one of two academic centres between 1990 and 2013. Specimen-confined disease was defined as pT2-pT3a node-negative PCa with negative surgical margins. The receiver-operator characteristic (ROC) curve was obtained to quantify the overall accuracy (area under the curve [AUC]) of the model in predicting specimen-confined disease. A calibration curve was then constructed to illustrate the relationship between the risk estimates obtained by the model (x-axis) and the observed proportion of specimen-confined disease (y-axis). The Kaplan-Meier method was used to assess biochemical recurrence (BCR)-free survival. ResultsPatients' median age and PSA level were 64 years and 21 ng/mL, respectively. The definition of high-risk PCa was based on PSA level only in 38.3%, a biopsy Gleason score >7 in 34.5%, a clinical stage >T2b in 6.9%, or a combination of these two or three factors in 20.3% of patients. Positive surgical margins were observed in 43.6%, with a rate of 14.8% in pT2 cancers and lymph node metastasis in 12.1% of patients. pT stage was pT0 in 0.9%, pT2 in 28.9%, pT3a in 37.5% and pT3b-4 in 32.7% of patients. Overall, 44.4% of patients (N = 232) had specimen-confined disease. PSA and cT stage were independently predictive of specimen-confined disease. The median (range) 2-, 5-, and 8-year BCR-free survival rates were significantly higher in specimen-confined disease as compared with non-specimen-confined disease: 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)% and 55.08 (41.49-66.74) vs 19.52 (12.50-27.70)%, respectively (P < 0.001). The 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 to 0.5, the odds of extracapsular extension were underestimated. ConclusionsThis external validation of the Briganti nomogram shows relevant accuracy, although the relative imprecision for intermediate risk may limit its clinical relevance. Our follow-up findings confirm the large proportion of specimen-confined PCa with good oncological outcomes in this heterogeneous subgroup of patients with high-risk PCa.

The role for surgeryin high-risk prostate cancer

“…Mearini et al [11] performed an external validation of this nomogram in 623 patients with high-risk PCa according to the D'Amico classification between 2007 and 2011, and found an acceptable accuracy (Area Under Curve (AUC) = 66.3 %) with a perfect calibration characteristics of the nomogram in predicting the probability of specimen confined cancer in this heterogeneous group of patients. Those results were recently supported by Roumiguié et al [12] in their cohort of 523 patients undergoing RP and bilateral lymph node dissection for high-risk PCa. The AUC was of 64.7 % showing a relevant accuracy of the model.…”

“…Although most series are retrospective and linked with a low level of evidence and thus a low grade of recommendations in [12] found PSA and cT stage to be independently predictive for organ-confined disease whereas for Mearini et al [11], only PSA was a significant predictor on multivariate analysis. On the contrary, Arcangeli et al [26] compared 162 patients with high-risk PCa undergoing external RT plus androgen deprivation to 122 patients treated with surgery at the same period and found more favorable outcomes in the RT group.…”

A novel tool for predicting extracapsular extension during graded partial nerve sparing in radical prostatectomy

“…Knowledge of the presence and extent of extracapsular extension (ECE) before surgery would help surgeons tailor the amount of NS. Several tools can predict the presence of ECE or other outcomes and most of them are based on routinely available variables . However, to our knowledge, there are no algorithms supporting preoperative planning with quantification not only of the presence of ECE but of the amount of ECE, this information is crucial in order to make an appropriate, standardised decision between a full NS, a partial NS, or a wide excision.…”

Surgery for high-risk prostate cancer and metastatic prostate cancer

“…26 Those results were corroborated by Hinev et al, 27 who found that SCD and negative lymph node involvement were the only 2 independent prognostic variables for survival in patients with PSA 4 20 ng/mL who underwent radical prostatectomy as a first-line treatment for high-risk prostate cancer. Roumiguie et al, 28 after analyzing 523 patients with high-risk prostate cancer who underwent RP and BPLND, also demonstrated that BCR-free survival was improved in SCD compared with those without (P o 0.0001). Mearini et al, 29 using data from 176 patients with high-risk prostate cancer who underwent initial RP, showed that BCR and CSS in SCD was superior to that of non-SCD (56.2% and 97.7% vs 40.8% and 92.8%, respectively).…”