Difference between kidney function by cystatin C versus creatinine and association with muscle mass and frailty.

BACKGROUND: A higher difference in estimated glomerular filtration rate by cystatin C versus creatinine (eGFRDiff = eGFRCys - eGFRCreat) is associated with decreased frailty risk. Since eGFRCreat is influenced by muscle more than eGFRCys, muscle mass may explain this association. Previous work could not account for this when considering regional muscle measures by imaging. Deuterated creatine (D3Cr) dilution measures whole body muscle mass (kilograms). We aimed to determine whether eGFRDiff is associated with D3Cr muscle mass and whether muscle mass explains the association between eGFRDiff and frailty. METHODS: Cross-sectional analysis within the multicenter MrOS Study at Year 14 (visit 4). 490 men of the original cohort of 5994 MrOS participants (aged ≥65 at enrollment) were included. Exposure was eGFRDiff (= eGFRCys - eGFRCreat), calculated using CKD-EPI equations 2012/2021. Primary outcome was D3Cr muscle mass. Secondary outcome was phenotypic pre-frailty (one or two criteria) and frailty (≥three criteria) including the following: weight loss, weakness, slow gait, physical activity, poor energy. The association of eGFRDiff with D3Cr muscle mass was examined by linear regression, that with prefrailty / frailty by multinomial logistic regression. RESULTS: Mean ± SD age was 84 ± 4 years, eGFRCreat 68 ± 16, eGFRCys 52 ± 16, eGFRDiff -15 ± 12 mL/min/1.73 m2 and D3Cr muscle mass 24 ± 4 kg. For each SD increment in eGFRDiff, D3Cr muscle mass was 1.4 kg higher on average, p < 0.0001 (fully adjusted). Higher eGFRDiff was associated with lower odds of frailty (OR = 0.63 95% CI [0.45;0.89]), but this was partially attenuated and insignificant after additionally adjusting for D3Cr muscle mass (OR = 0.85 95% CI [0.58; 1.24]). CONCLUSIONS: Higher eGFRDiff is associated with lower odds of frailty among late-life men. D3Cr muscle mass accounts for some of this association. This suggests that non-GFR determinants of creatinine and cystatin C, such as muscle mass, play a role in explaining the association of eGFRDiff with frailty. Future studies are needed to confirm.

Age-Related Differences in Oncological Outcomes in Renal Cell Carcinoma: Impact of Functional Conservation as Measured by Postoperative eGFR.

INTRODUCTION: We sought to determine whether loss of renal function increases risk of recurrence and metastases in renal cell carcinoma (RCC), and whether this impact was age-related. MATERIALS AND METHODS: We performed a retrospective analysis of the International Marker Consortium for Renal Cancer (INMARC) registry. Patients were separated into younger (<65 years old) and elder (≥65 years old) age groups, and rates of de novo estimated glomerular filtration rate (eGFR<45 mL/min/1.73m2 [eGFR<45]) were calculated. Multivariable analysis (MVA) was conducted for predictors of progression-free survival (PFS) and all-cause mortality (ACM). Kaplan-Meier Analysis (KMA) was conducted for PFS and overall survival (OS) in younger and elder age groups stratified by functional status. RESULTS: We analyzed 1805 patients (1113 age<65, 692 age≥65). On MVA in patients <65, de novo eGFR<45 was independently associated with greater risk for worsened progression (HR=1.61, P=.038) and ACM (HR=1.82, P=.018). For patients ≥65, de novo eGFR<45 was not independently associated with progression (P=.736), or ACM (P=.286). Comparing patients with de novo eGFR<45 vs. eGFR ≥45, KMA demonstrated worsened 5-year PFS and OS in patients <65 (PFS: 68% vs. 86%, P<.001; OS: 73% vs. 90%, P<.001), while in patients ≥65, only 5-year OS was worsened (77% vs. 81%, P<.021). CONCLUSION: Development of de novo eGFR<45 was associated with more profound impact on patients <65 compared to patients ≥65, being an independent risk factor for PFS and ACM. The mechanisms of this phenomenon are unclear but underscore desirability for nephron preservation when safe and feasible in younger patients.

Outcomes of Lymph Node Dissection in Nephroureterectomy in the Treatment of Upper Tract Urothelial Carcinoma: Analysis of the ROBUUST Registry.

PURPOSE: We sought to evaluate outcomes of lymph node dissection (LND) in patients with upper tract urothelial carcinoma. MATERIALS AND METHODS: We performed a multicenter retrospective analysis utilizing the ROBUUST (for RObotic surgery for Upper Tract Urothelial Cancer Study) registry for patients who did not undergo LND (pNx), LND with negative lymph nodes (pN0) and LND with positive nodes (pN+). Primary and secondary outcomes were overall survival (OS) and recurrence-free survival (RFS). Multivariable analyses evaluated predictors of outcomes and pathological node positivity. Kaplan-Meier analyses (KMAs) compared survival outcomes. RESULTS: A total of 877 patients were analyzed (LND performed in 358 [40.8%]/pN+ in 73 [8.3%]). Median nodes obtained were 10.2 for pN+ and 9.8 for pN0. Multivariable analyses noted increasing age (OR 1.1, p <0.001), pN+ (OR 3.1, p <0.001) and pathological stage pTis/3/4 (OR 3.4, p <0.001) as predictors for all-cause mortality. Clinical high-grade tumors (OR 11.74, p=0.015) and increasing tumor size (OR 1.14, p=0.001) were predictive for lymph node positivity. KMAs for pNx, pN0 and pN+ demonstrated 2-year OS of 80%, 86% and 42% (p <0.001) and 2-year RFS of 53%, 61% and 35% (p <0.001), respectively. KMAs comparing pNx, pN0 ≥10 nodes and pN0 <10 nodes showed no significant difference in 2-year OS (82% vs 85% vs 84%, p=0.6) but elicited significantly higher 2-year RFS in the pN0 ≥10 group (60% vs 74% vs 54%, p=0.043). CONCLUSIONS: LND during nephroureterectomy in patients with positive lymph nodes provides prognostic data, but is not associated with improved OS. LND yields ≥10 in patients with clinical node negative disease were associated with improved RFS. In high-grade and large tumors, lymphadenectomy should be considered.

Disparities in Telemedicine Utilization for Urology Patients During the COVID-19 Pandemic.

OBJECTIVE: To determine the odds of accessing telemedicine either by phone or by video during the COVID-19 pandemic. METHODS: We performed a retrospective study of patients who were seen at a single academic institution for a urologic condition between March 15, 2020 and September 30, 2020. The primary outcome was to determine characteristics associated with participating in a telemedicine appointment (video or telephone) using logistic regression multivariable analysis. We used a backward model selection and variables that were least significant were removed. We adjusted for reason for visit, patient characteristics such as age, sex, ethnicity, race, reason for visit, preferred language, and insurance. Variables that were not significant that were removed from our final model included median income estimated by zip code, clinic location, provider age, provider sex, and provider training. RESULTS: We reviewed 4234 visits: 1567 (37%) were telemedicine in the form of video 1402 (33.1%) or telephone 164 (3.8%). The cohort consisted of 2516 patients, Non-Hispanic White (n = 1789, 71.1%) and Hispanic (n = 417, 16.6%). We performed multivariable logistic regression analysis and demonstrated that patients who were Hispanic, older, or had Medicaid insurance were significantly less likely to access telemedicine during the pandemic. We did not identify differences in telemedicine utilization when stratifying providers by their age, sex, or training type (physician or advanced practice provider). CONCLUSION: We conclude that there are differences in the use of telemedicine and that this difference may compound existing disparities in care. Additionally, we identified that these differences were not associated with provider attributes. Further study is needed to overcome barriers in access to telemedicine.

Evaluation of the association of health care system access with kidney cancer surgical outcomes for hispanic and non-hispanic white patients.

OBJECTIVE: To determine the impact of health care system access on outcomes for Hispanic and Non-Hispanic White patients with renal cell carcinoma (RCC). METHODS: We retrospectively analyzed Hispanic and non-Hispanic White patients diagnosed with localized RCC between 2007 and 2020. We used Health Resources and Services Administration criteria to identify patients living in Medically Underserved Areas (MUA). Primary outcome all-cause mortality and cancer-specific survival using Log Rank test on Kaplan Meier Analysis. Secondary outcome was all-cause mortality and cancer specific survival on Cox Regression when adjusting for risk factors. RESULTS: We analyzed 774 patients, 246 (31.8%) Hispanic patients and 528 (68.2%) Non-Hispanic White patients. Hispanic ethnicity was associated with lower risk of ACM (HR 0.53, P = 0.019) and there was no difference for cancer specific survival (HR 0.57, P = 0.059). Living in a MUA was associated with worse all-cause mortality (P = 0.010) but not cancer specific survival (CSS) (P = 0.169). Comparing Hispanic and Non-Hispanic Whites, KMA revealed no difference in 5-year all-cause mortality (83.1% vs. 78.8%, P = 0.254) and 5-year CSS (85.7% vs. 85.4%, P = 0.403). CONCLUSIONS: Hispanics had lower all-cause mortality risk and no significant differences in 5-year overall survival and CSS compared to non-Hispanic Whites. Our findings indicate that tertiary referral centers may help mitigate inequalities in access to care.

Evaluation of Insurance Coverage and Cancer Stage at Diagnosis Among Low-Income Adults With Renal Cell Carcinoma After Passage of the Patient Protection and Affordable Care Act.

Importance: The association of the Patient Protection and Affordable Care Act (ACA) with insurance status and cancer stage at diagnosis among patients with renal cell carcinoma (RCC) is unknown. Objective: To test the hypothesis that the ACA may be associated with increased access to care through expansion of insurance, which may vary based on income. Design, Setting, and Participants: This retrospective cohort analysis included patients diagnosed with RCC from January 1, 2010, to December 31, 2016, in the National Cancer Database. Data were analyzed from July 1 to December 31, 2020. The periods from 2010 to 2013 and from 2014 to 2016 were defined as pre- and post-ACA implementation, respectively. Patients were categorized as living in a Medicaid expansion state or not. Exposures: Implementation of the ACA. Main Outcomes and Measures: The absolute percentage change (APC) of insurance coverage was calculated before and after ACA implementation in expansion and nonexpansion states. Secondary outcomes included change in stage at diagnosis, difference in the rate of insurance change, and change in localized disease between expansion and nonexpansion states. Adjusted difference-in-difference modeling was performed. Results: The cohort included 78 099 patients (64.7% male and 35.3% female; mean [SD] age, 54.66 [6.46] years), of whom 21.2% had low, 46.2% had middle, and 32.6% had high incomes. After ACA implementation, expansion states had a lower proportion of uninsured patients (adjusted difference-in-difference, -1.14% [95% CI, -1.98% to -1.41%]; P = .005). This occurred to the greatest degree among low-income patients through the acquisition of Medicaid (APC, 11.0% [95% CI, 8.6%-13.3%]; P < .001). Implementation of the ACA was also associated with an increase in detection of stage I and II disease (APC, 4.0% [95% CI, 1.6%-6.3%]; P = .001) among low-income patients in expansion states. Conclusions and Relevance: Among patients with RCC, ACA implementation was associated with an increase in insurance coverage status in both expansion and nonexpansion states for all income groups, but to a greater degree in expansion states. The proportion of patients with localized disease increased among low-income patients in both states. These data suggest that ACA implementation is associated with earlier RCC detection among lower-income patients.

Utilization of renal mass biopsy in patients with localized renal cell carcinoma: A population-based study utilizing the National Cancer Database.

OBJECTIVE: To evaluate trends and factors predicting use of renal mass biopsy (RMB) for localized Renal Cell Carcinoma in the United States (US) in the context of current guidelines recommendations. METHODS: We queried the National Cancer Database for cT1-cT3N0M0 Renal Cell Carcinoma diagnosed between 2004 and 2015. Temporal trends of RMB were characterized based on tumor size, treatment (partial nephrectomy [PN], radical nephrectomy [RN], ablation, and no treatment), age and Charlson Comorbidity Index with slopes compared using analysis of variance. Multivariable analysis was used to determine factors associated with use of RMB. RESULTS: Of 338,252 patients analyzed, 11.9% (40,276) underwent RMB. Use of RMB increased throughout the study period from 1,586 (7.6%) in 2004 to 5,629 (16.2%) in 2015 (P < 0.001). Use of RMB increased greatest for ablation (27 to 63%, P < 0.001) and tumors 2-4 cm (9 to 20%, P < 0.001). Multivariable analysis showed year of diagnosis (OR = 1.06; P < 0.001), higher education (OR = 1.09; P < 0.001) and insured status (OR = 1.23; P < 0.001) were associated with increased RMB. Compared to tumors ≤2 cm, tumors 2.1-4 cm (OR = 1.36; P=<0.001), 4.1-7 cm (OR = 1.18; P <0.001) and >7 cm (OR = 1.05; P = 0.03) were associated with higher rates of RMB. Compared to RN, PN was not associated with increased RMB (OR = 1.00; P = 0.92), while ablation (OR = 10.90; P < 0.001) and no surgical treatment (OR = 4.83; P < 0.001) were. CONCLUSION: RMB utilization increased overall, with largest increase associated with ablation. Nonetheless, only two-thirds of patients underwent RMB with ablation, suggesting persistent underutilization. Rates of RMB for tumors ≤2 cm and in those undergoing no treatment increased less, suggesting less utilization for surveillance. However, rates for tumors >2-4 cm increased more, suggesting selective utilization of RMB to guide decision-making and risk stratification in small renal masses.

Publisher Correction: Interplay between hypoxia and androgen controls a metabolic switch conferring resistance to androgen/AR-targeted therapy.

The original version of this Article contained errors in Fig. 7. In panels e and f, the graph titles incorrectly read 'LNCaP-AdtNs' and 'LAPC4-AdtNs', respectively. These errors have now been corrected in both the PDF and HTML versions of the Article.

Interplay between hypoxia and androgen controls a metabolic switch conferring resistance to androgen/AR-targeted therapy.

Despite recent advances, the efficacy of androgen/androgen receptor (AR)-targeted therapy remains  limited for many patients with metastatic prostate cancer. This is in part because prostate cancers adaptively switch to the androgen/AR-independent pathway for survival and growth, thereby conferring therapy resistance. Tumor hypoxia is considered as a major cause of treatment resistance. However, the exact mechanism is largely unclear. Here we report that chronic-androgen deprivation therapy (ADT) in the condition of hypoxia induces adaptive androgen/AR-independence, and therefore confers resistance to androgen/AR-targeted therapy, e.g., enzalutamide. Mechanistically, this is mediated by glucose-6-phosphate isomerase (GPI), which is transcriptionally repressed by AR in hypoxia, but restored and increased by AR inhibition. In turn, GPI maintains glucose metabolism and energy homeostasis in hypoxia by redirecting the glucose flux from androgen/AR-dependent pentose phosphate pathway (PPP) to hypoxia-induced glycolysis pathway, thereby reducing the growth inhibitory effect of enzalutamide. Inhibiting GPI overcomes the therapy resistance in hypoxia in vitro and increases enzalutamide efficacy in vivo.