ABSTRACT
Background: The von Hippel-Lindau disease (VHL) is a hereditary cancer syndrome with multifocal, bilateral cysts and solid tumors of the kidney. Surgical management may include multiple extirpative surgeries, which ultimately results in parenchymal volume loss and subsequent renal function decline. Recent studies have utilized parenchyma volume as an estimate of renal function prior to surgery for renal cell carcinoma; however, it is not yet validated for surgically altered kidneys with multifocal masses and complex cysts such as are present in VHL. Objective: We sought to validate a magnetic resonance imaging (MRI)-based volumetric analysis with mercaptoacetyltriglycine (MAG-3) renogram and postoperative renal function. Design setting and participants: We identified patients undergoing renal surgery at the National Cancer Institute from 2015 to 2020 with preoperative MRI. Renal tumors, cysts, and parenchyma of the operated kidney were segmented manually using ITK-SNAP software. Outcome measurements and statistical analysis: Serum creatinine and urinalysis were assessed preoperatively, and at 3- and 12-mo follow-up time points. Estimated glomerular filtration rate (eGFR) was calculated using serum creatinine-based CKD-EPI 2021 equation. A statistical analysis was conducted on R Studio version 4.1.1. Results and limitations: Preoperative MRI scans of 113 VHL patients (56% male, median age 48 yr) were evaluated between 2015 and 2021. Twelve (10.6%) patients had a solitary kidney at the time of surgery; 59 (52%) patients had at least one previous partial nephrectomy on the renal unit. Patients had a median of three (interquartile range [IQR]: 2-5) tumors and five (IQR: 0-13) cysts per kidney on imaging. The median preoperative GFR was 70 ml/min/1.73 m2 (IQR: 58-89). Preoperative split renal function derived from MAG-3 studies and MRI split renal volume were significantly correlated (r = 0.848, p < 0.001). On the multivariable analysis, total preoperative parenchymal volume, solitary kidney, and preoperative eGFR were significant independent predictors of 12-mo eGFR. When only considering patients with two kidneys undergoing partial nephrectomy, preoperative parenchymal volume and eGFR remained significant predictors of 12-mo eGFR. Conclusions: A parenchyma volume analysis on preoperative MRI correlates well with renogram split function and can predict long-term renal function with added benefit of anatomic detail and ease of application. Patient summary: Prior to kidney surgery, it is important to understand the contribution of each kidney to overall kidney function. Nuclear medicine scans are currently used to measure split kidney function. We demonstrated that kidney volumes on preoperative magnetic resonance imaging can also be used to estimate split kidney function before surgery, while also providing essential details of tumor and kidney anatomy.
ABSTRACT
INTRODUCTION AND OBJECTIVE: Von Hippel-Lindau (VHL) is a hereditary cancer syndrome characterized by bilateral, multifocal renal masses. The cumulative impact of extirpative surgery can depreciate renal function and render patients anephric. In the larger end-stage renal disease population, renal transplant offers both excellent quality of life and functional renal replacement. This case control study aims to examine and compare oncologic and functional outcomes of patients who have undergone renal transplant as renal replacement therapy (RRT) to those who remain anephric. METHODS: Patient charts were retrospectively reviewed of patients with germline testing confirmed VHL between 1980 and 2022 for transplant, all prior surgical history (within and outside the NCI), renal function and graft outcomes. Overall survival (OS) was determined from years after radical nephrectomy, and graft time was defined as years of graft function from initial transplant until failure or patient death. Graft survival was determined as time between transplant(s) to last follow up. Kaplan-Meier analysis was conducted to compare graft times of anephric VHL patients to those with transplanted kidneys. RESULTS: A total of 23 VHLD patients were identified as either anephric or candidates for transplant. Out of this cohort, 11 total VHLD received 12 total kidney grafts. Median wait time from nephrectomy to transplant was 22.6 months (IQR: 1.02-40.25 months). Median age at transplant was 32 years (IQR: 23-54 years). OS at 5 and 10 years of anephric patients who did not receive a transplant was 33% and 16.7%, respectively. OS rates of the transplant cohort at 10, 15, and 20 years were 91%, 78%, and 58% years, respectively. Median graft time was 161 months (IQR: 56-214 months). Graft survival at 10, 15, and 20 years was 69.8%, 69.8%, and 26.2%, respectively. CONCLUSIONS: We demonstrate that transplant recipients have decreased mortality with no difference in cancer recurrence compared to those who do not receive renal transplant for RRT. This data can aid in informing providers of the optimal window for early RRT planning in VHL, while also improving patient counseling.
