Understanding racial disparities in renal cell carcinoma incidence: estimates of population attributable risk in two US populations

Global epidemiology of kidney cancer

Kidney cancer (KC) is a disease with a rising worldwide incidence estimated at 400 000 new cases annually, and a worldwide mortality rate approaching 175 000 deaths per year. Current projections suggest incidence continuing to increase over the next decade, emphasizing the urgency of addressing this significant global health trend. Despite the overall increases in incidence and mortality, striking social disparities are evident. Low- and middle-income countries bear a disproportionate burden of the disease, with higher mortality rates and later-stage diagnoses, underscoring the critical role of socioeconomic factors in disease prevalence and outcomes. The major risk factors for KC, including smoking, obesity, hypertension and occupational exposure to harmful substances, must be taken into account. Importantly, these risk factors also often contribute to kidney injury, a condition that the review identifies as a significant, yet under-recognized, precursor to KC. Finally, the indispensable role of nephrologists is underscored in managing this complex disease landscape. Nephrologists are at the forefront of detecting and managing kidney injuries, and their role in mitigating the risk of KC is becoming increasingly apparent. Through this comprehensive analysis, we aim to facilitate a more nuanced understanding of KC's epidemiology and determinants providing valuable insights for researchers, clinicians and policymakers alike.

mTOR Regulation of N-Myc Downstream Regulated 1 (NDRG1) Phosphorylation in Clear Cell Renal Cell Carcinoma

The mechanistic target of rapamycin (mTOR) kinase is a component of two signaling complexes that are known as mTOR complex 1 (mTORC1) and mTORC2. We sought to identify mTOR-phosphorylated proteins that are differently expressed in clinically resected clear cell renal cell carcinoma (ccRCC) relative to pair-matched normal renal tissue. Using a proteomic array, we found N-Myc Downstream Regulated 1 (NDRG1) showed the greatest increase (3.3-fold) in phosphorylation (on Thr346) in ccRCC. This was associated with an increase in total NDRG1. RICTOR is a required subunit in mTORC2, and its knockdown decreased total and phospho-NDRG1 (Thr346) but not NDRG1 mRNA. The dual mTORC1/2 inhibitor, Torin 2, significantly reduced (by ~100%) phospho-NDRG1 (Thr346). Rapamycin is a selective mTORC1 inhibitor that had no effect on the levels of total NDRG1 or phospho-NDRG1 (Thr346). The reduction in phospho-NDRG1 (Thr346) due to the inhibition of mTORC2 corresponded with a decrease in the percentage of live cells, which was correlated with an increase in apoptosis. Rapamycin had no effect on ccRCC cell viability. Collectively, these data show that mTORC2 mediates the phosphorylation of NDRG1 (Thr346) in ccRCC. We hypothesize that RICTOR and mTORC2-mediated phosphorylation of NDRG1 (Thr346) promotes the viability of ccRCC cells.

The Latinx Disparity in Surgery for Kidney Cancer: Data from The South Texas Region

The South Texas region, with a predominantly Latinx population, has a very high incidence of renal cell carcinoma (RCC), including those with tumor extending into the major blood vessels called venous tumor thrombus (VTT). There is currently no data on outcomes of Latinx patients with VTT as most published studies are from predominantly Caucasian population. Therefore, we performed this study to fill an urgent, unmet need. We reviewed patients who underwent radical nephrectomy with removal of VTT (called tumor thrombectomy) between 2015 and 2020. We collected data on demographics, clinical, pathological characteristics and outcomes of patients. Univariate and multivariate Cox regression analyses were used to evaluate the associations between ethnicity and disease progression or survival. We identified 112 patients, of which 67 (62%) were Latinx, and 41 (38%) were non-Latinx. Approximately 60% of patients had Level II-IV VTT; Latinx presented with a higher level of tumor thrombus (p=0.046). Latinx patients had a higher rate of no insurance (11% vs. 27%, p=0.04) and were more likely to lost to follow-up after surgery (22.4% vs. 13.3%, p=0.23) compared to non-Latinx. Fewer Latinx received systemic therapy (28% vs. 42%; p=0.13). Ninety-day mortality for the entire cohort was 3.8%. The Latinx population in the South Texas region present late, with advanced thrombus level, and do not have access to systemic therapy. Given symptomatic disease, surgical treatment, if feasible, is their only option. Our results highlight disparate treatment patterns which require further investigation and health-care policy changes.

A Review of Research on Disparities in the Care of Black and White Patients With Cancer in Detroit

Racial disparities in cancer incidence and outcomes are well-documented in the US, with Black people having higher incidence rates and worse outcomes than White people. In this review, we present a summary of almost 30 years of research conducted by investigators at the Karmanos Cancer Institute's (KCI's) Population Studies and Disparities Research (PSDR) Program focusing on Black-White disparities in cancer incidence, care, and outcomes. The studies in the review focus on individuals diagnosed with cancer from the Detroit Metropolitan area, but also includes individuals included in national databases. Using an organizational framework of three generations of studies on racial disparities, this review describes racial disparities by primary cancer site, disparities associated with the presence or absence of comorbid medical conditions, disparities in treatment, and disparities in physician-patient communication, all of which contribute to poorer outcomes for Black cancer patients. While socio-demographic and clinical differences account for some of the noted disparities, further work is needed to unravel the influence of systemic effects of racism against Black people, which is argued to be the major contributor to disparate outcomes between Black and White patients with cancer. This review highlights evidence-based strategies that have the potential to help mitigate disparities, improve care for vulnerable populations, and build an equitable healthcare system. Lessons learned can also inform a more equitable response to other health conditions and crises.

Renal Cell Carcinoma Health Disparities in Stage and Mortality among American Indians/Alaska Natives and Hispanic Americans: Comparison of National Cancer Database and Arizona Cancer Registry Data

Simple Summary

This study assessed renal cell carcinoma disparities in American Indians/Alaska Natives and Hispanic Americans using the National Cancer Database and the Arizona Cancer Registry, focusing on advanced-stage and mortality. Renal cell carcinoma disparities in American Indians/Alaska Natives have been partially explained by neighborhood socioeconomic factors and residence (rural or urban) pattern, but not in Hispanic Americans. Greater health disparities in renal cell carcinoma stage and mortality for Hispanic Americans and renal cell carcinoma mortality for American Indians/Alaska Natives were observed at the Arizona state level compared to national levels.

Abstract

Renal cell carcinoma (RCC) is one of the top 10 cancers in the United States. This study assessed RCC health disparities in American Indians/Alaska Natives (AIs/ANs) and Hispanic Americans (HAs) focusing on advanced-stage and mortality. RCC patients’ data were obtained from the National Cancer Database (NCDB) and Arizona Cancer Registry (ACR). Logistic and Cox regression analyses were performed to ascertain the effect of race/ethnicity on stage and mortality, adjusting for neighborhood socioeconomic factors, rural/urban residence pattern, and other factors. In both data sets, AIs/ANs had significantly increased odds of advanced-stage RCC in the unadjusted model, but not in adjusted models. Mexican Americans had higher odds of advanced-stage compared to non-Hispanic Whites in NCDB (OR 1.22, 95% CI: 1.11–1.35) and ACR (OR 2.02, 95% CI: 1.58–2.58), even after adjusting for neighborhood characteristics. AIs/ANs did not show increased mortality risk in NCDB after adjusting for neighborhood characteristics, while the association remained significant in ACR (HR 1.33, 95% CI: 1.03–1.72). The great risk of all-cause and RCC-specific mortality was observed in U.S.-born Mexican Americans in Arizona (HR 3.21, 95% CI: 2.61–3.98 and sub-distribution HR 2.79, 95% CI: 2.05–3.81). RCC disparities in AIs/ANs is partially explained by neighborhood factors, but not in HAs.