Impact of the time elapsed between prostate biopsy and surgery on the accuracy of nomograms predicting lymph node invasion in patients with clinically localized prostate cancer.

ABSTRACT

We aimed to investigate whether the performance characteristics of available nomograms predicting lymph node invasion (LNI) in prostate cancer patients undergoing radical prostatectomy (RP) change according to the time elapsed between diagnosis and surgery. We identified 816 patients who underwent RP with extended pelvic lymph node dissection (ePLND) after combined prostate biopsy at 6 referral centers. We plotted the accuracy (ROC-derived area under the curve [AUC]) of each Briganti nomogram according to the time elapsed between biopsy ad RP. We then tested whether discrimination of the nomograms improved after accounting for the time elapsed between biopsy ad RP. The median time between biopsy and RP was 3 months. The LNI rate was 13%. The discrimination of each nomogram decreased with increasing time elapsed between biopsy and surgery, where the AUC of the 2019 Briganti nomogram was 88% vs. 70% for men undergoing surgery <2 vs. >6 months from the biopsy. The addition of the time elapsed between biopsy ad RP improved the accuracy of all available nomograms (P < 0.003), with the Briganti 2019 nomogram showing the highest discrimination. Clinicians should be aware that the discrimination of available nomograms decreases according to the time elapsed between diagnosis and surgery. The indication of ePLND should be carefully evaluated in men below the LNI cut-off who had a diagnosis more than 6 months before RP. This has important implications when considering the longer waiting lists related to the impact of COVID-19 on healthcare systems.