Development And Validation Of Preoperative Nomogram In The Prediction Of Unfavorable High-grade Small Renal Masses

Purpose:In recent decades,with the widespread use of abdominal CT and urinary B-ultrasound,there has been an increase in the incidence of renal cell carcinoma(RCC).Small renal masses(SRMs)refers to T1 a stage renal cancer that is confined to the kidney and has a tumor largest dimension ?4 cm.It is currently recognized that surgery is the preferred treatment for SRMs.However,some scholars have suggested that due to the diversity of biological manifestations of SRMs,the use of active surveillance has been recommended as an alternative option in the case of some patients with low-grade SRMs.However,there is still no relevant research on preoperative prediction of high-grade SRMs.Therefore,in this study,we aim to screen out clinical predictors of high-grade SRMs,and developed a nomogram for the purpose of predicting the presence of high-grade SRMs on the basis of the patient information provided.This could potentially be a new and improved option for clinicians when performing preoperative evaluation and selecting the best treatment regimen for SRMs.Methods:A total of 329 patients(consisting of development and validation cohort)who had undergone nephrectomy and pathological diagnosis for SRMs in the Department of Urology,Second Hospital of Tianjin Medical University between January 2013 and May 2016 retrospectively were recruited for the present study.All preoperative information,including clinical predictors,hematological indicators,and CT predictors were obtained.Lasso regression model was used for data dimension reduction and feature selection.Multivariable logistic regression analysis was applied for the establishment of the predicting model.The performance of the nomogram was assessed with respect to its calibration and discrimination properties and externally validated.Results:The total cohort subjects were then randomly assigned into the development cohort(217 patients)and validation cohort(112 patients)groups.There were no significant differences in the clinical,hematological and CT characteristics of high-grade tumors between the two cohorts.However,low-grade tumors were significantly smaller than high-grade tumors(2.9±0.8cm vs.3.5±0.4cm;p < 0.001). As for the predictors derived from CT imaging,the presence of necrosis,ill-defined tumor contour,tumor exophytic properties,and collecting system oppression were significantly associated with high grade tumors(all p ? 0.05).Based on these parameters,the nomogram was evaluated to have an effective discrimination and calibration ability,and the C-index was found to be 0.883 after internal validation and 0.887 following external validation.Conclusion:Based on the aforementioned findings,it can be concluded that CT imaging based preoperative nomogram is an effective predictor of SRMs and hence can be used in the preoperative evaluation of SRMs,due to its calibration and discrimination abilities.It may help clinicians in clinical decision-making.