Development and Validation of Nomograms Based on Nutritional Risk Index for Predicting Extracapsular Extension and Seminal Vesicle Invasion in Patients Undergoing Radical Prostatectomy

Ze Nan Liu; Zi Ang Li; Ji De He; Jia Long Wu; Lei Qiu; Zhen Kun Zhao; Min Lu; Hai Bi; Jian Lu

doi:10.14740/wjon1718

Development and Validation of Nomograms Based on Nutritional Risk Index for Predicting Extracapsular Extension and Seminal Vesicle Invasion in Patients Undergoing Radical Prostatectomy

World J Oncol. 2023 Dec;14(6):505-517. doi: 10.14740/wjon1718. Epub 2023 Nov 18.

Authors

Ze Nan Liu^{1

2}, Zi Ang Li^{1

2}, Ji De He¹, Jia Long Wu¹, Lei Qiu¹, Zhen Kun Zhao¹, Min Lu³, Hai Bi⁴, Jian Lu¹

Affiliations

¹ Department of Urology, Peking University Third Hospital, Beijing, China.
² These authors contributed equally to this work.
³ Department of Pathology, Peking University Third Hospital, Beijing, China.
⁴ Department of Urology, Shanghai General Hospital, Shanghai, China.

Abstract

Background: The aim of the study was to investigate the predictive value of the nutritional risk index (NRI) for extracapsular extension (ECE) and seminal vesicle invasion (SVI) in prostate cancer (PCa) patients undergoing radical prostatectomy (RP), and further develop and validate predictive nomograms for ECE and SVI based on the NRI.

Methods: We retrospectively analyzed 734 PCa patients who underwent RP between 2010 and 2020 in the Department of Urology at Peking University Third Hospital. The enrolled patients were randomly divided into a primary cohort (n = 489) and a validation cohort (n = 245) in a 2:1 manner. The baseline NRI of patients was calculated using serum albumin level and body mass index, and a malnutrition status was defined as NRI ≤ 98. Univariate and multivariate logistic regression analyses were conducted to identify predictors for ECE and SVI. Nomograms for predicting ECE and SVI were established based on the results of the multivariate logistic regression analysis. The performance of the nomograms was estimated using Harrell's concordance index (C-index), the area under curve (AUC) of receiver operating characteristic (ROC) curves and the calibration curves.

Results: In the primary cohort, 70 (14.3%) patients with NRI ≤ 98 were classified as malnutrition, while the remaining 419 (85.7%) patients with NRI > 98 were considered to have normal nutrition. The nomograms for predicting ECE and SVI shared common factors including NRI, percentage of positive biopsy cores (PPC) and biopsy Gleason score, while prostate-specific antigen (PSA) levels and PSA density (PSAD) were only incorporated in ECE nomogram. The C-indexes of the nomograms for predicting ECE and SVI were 0.785 (95% confidence interval (CI): 0.745 - 0.826) and 0.852 (95% CI: 0.806 - 0.898), respectively. The calibration curves demonstrated excellent agreement between the predictions by the nomograms and the actual observations. The results remained reproducible when the nomograms were applied to the validation cohort.

Conclusions: The NRI is significantly associated with ECE and SVI in PCa patients. The nomogram established based on the NRI in our study can provide individualized risk estimation for ECE and SVI in PCa patients, and may be valuable for clinicians in making well-informed decisions regarding treatment strategies and patient management.

Keywords: Extracapsular extension; Nomogram; Nutritional risk index; Prostate cancer; Radical prostatectomy; Seminal vesicle invasion.

Grants and funding

This work was supported by grants from Beijing Natural Science Foundation (No. Z200027 and No. L212051) and National Natural Science Foundation of China (No. 62331001).