The association between chronic renal failure and renal cell carcinoma may differ between black and white Americans

Blood purification therapy in chronic renal failure and its impact on renal index, serological index, and inflammatory factors

Introduction

This study aimed to explore the clinical effects of blood purification therapy in patients with chronic renal disease, measured by renal function index and inflammation.

Methodology

Data were collected from a tertiary care hospital in Pakistan between June 2022 and September 2023. Eighty-four patients undergoing maintenance hemodialysis for chronic renal failure were retrospectively included in this cohort.

Results

Age, sex, BMI, course of disease, primary disease, and educational level were not related to the response to blood purification treatment. Blood purification therapy positively affected renal function, serological indices, and inflammatory factors (P<0.05).

Conclusion

Blood purification therapy can improve toxin clearance and renal function and reduce inflammation. Therefore, the authors can conclude that this is an effective therapy for our population.

Mesenchymal-Epithelial Transition Kinase Inhibitor Therapy in Patients with Advanced Papillary Renal-Cell Carcinoma: A Systematic Review and Meta-Analysis

Papillary subtypes of renal-cell carcinoma (pRCC) represent 10-15% of the cases and commonly have MET alterations. This systematic review and single-arm meta-analysis evaluated MET inhibitor therapy (METi) efficacy and safety in adults with confirmed advanced pRCC. The search strategy included PubMed, Web-of-science, Cochrane, and Scopus. We used the DerSimonian/Laird random effect model for all analyses; p-value < 5% was considered significant, and heterogeneity was assessed with I2. Three clinical trials and six cohort studies were included with 504 patients; 31% were MET-driven. Our pooled analysis demonstrated an objective response rate (ORR) in MET-driven, MET-independent, and overall patients of: 36% (95%CI: 10-62), 0% (95%CI: 0-3), and 21% (95%CI: 1-41), respectively. One-year disease control and progression-free survival rates were, respectively, 70% (95%CI: 52-88) and 15% (95%CI: 10-20). Twelve- and twenty-four-month survival rates were, respectively, 43% (95%CI: 23-64) and 10% (95%CI: 0-30). The prevalence of adverse events of any grade and grades 3-5 were 96% (95%CI: 91-100) and 44% (95%CI: 37-50), respectively. We suggest METi has anti-tumor activity and is tolerable in patients with advanced pRCC.

Race/ethnicity and advanced stage of renal cell carcinoma in adults: results from surveillance, epidemiology, and end results program 2007-2015

Non-Hispanic Blacks were shown to have an earlier stage of renal cell carcinoma (RCC) at diagnosis compared to non-Hispanic Whites. It is less clear whether disparities in RCC staging occurs for other minority races/ethnicities. We aimed to assess the association between racial/ethnic minorities and stage at diagnosis of RCC, and test for potential effect modification by histological subtype. Sourced from the Surveillance, Epidemiology and End Results (SEER) database, patients ≥20 years diagnosed with RCC from 2007 to 2015 were included (n = 37 493). Logistic regression analyses were performed to assess the independent association between race/ethnicity [non-Hispanic White, non-Hispanic Black, non-Hispanic Asian Pacific Islander, non-Hispanic American Indian/Alaskan Native (AI/AN) and Hispanic] and advanced RCC stage at diagnosis (i.e. regional spread or distant metastasis). Interaction terms were tested and stratified regression was performed accordingly. Twenty-eight percent of patients had advanced RCC stage at diagnosis. After adjusting for age, gender, year of diagnosis, histological subtype and insurance status, compared to non-Hispanic Whites, non-Hispanic Blacks had lower odds of advanced stage at diagnosis [odds ratio (OR) = 0.79; 95% confidence interval (CI) = 0.72-0.87 for clear cell; OR = 0.48; CI = 0.30-0.78 for chromophobe and OR = 0.26; CI = 0.10-0.35 for other subtypes]. Higher odds of advanced stage at diagnosis were found for non-Hispanic AI/AN in clear cell (OR = 1.27; CI = 1.04-1.55) and for Hispanics in papillary subtypes (OR = 1.58; CI = 1.07-2.33). Racial disparities in the RCC stage at diagnosis varied according to histological subtype. Further investigation on the racial disparities reported is warranted to optimize detection and ultimately improve the prognosis of patients with RCC.

KDIGO Controversies Conference on onco-nephrology: understanding kidney impairment and solid-organ malignancies, and managing kidney cancer

The association between kidney disease and cancer is multifaceted and complex. Persons with chronic kidney disease (CKD) have an increased incidence of cancer, and both cancer and cancer treatments can cause impaired kidney function. Renal issues in the setting of malignancy can worsen patient outcomes and diminish the adequacy of anticancer treatments. In addition, the oncology treatment landscape is changing rapidly, and data on tolerability of novel therapies in patients with CKD are often lacking. Caring for oncology patients has become more specialized and interdisciplinary, currently requiring collaboration among specialists in nephrology, medical oncology, critical care, clinical pharmacology/pharmacy, and palliative care, in addition to surgeons and urologists. To identify key management issues in nephrology relevant to patients with malignancy, KDIGO (Kidney Disease: Improving Global Outcomes) assembled a global panel of multidisciplinary clinical and scientific expertise for a controversies conference on onco-nephrology in December 2018. This report covers issues related to kidney impairment and solid organ malignancies as well as management and treatment of kidney cancer. Knowledge gaps, areas of controversy, and research priorities are described.

Racial and ethnic differences in survival in contemporary metastatic renal cell carcinoma patients, according to alternative treatment modalities

PURPOSE

To test the association between African-American race and overall mortality (OM) rates in patients with metastatic renal cell carcinoma (mRCC).

METHODS

Within the Surveillance, Epidemiology, and End Results registry (2006-2015), we identified patients with clear cell (ccmRCC) and non-clear cell mRCC (non-ccmRCC). African-Americans, Caucasians, and Hispanics were identified. Stratification was made according to histology and treatments: (1) no treatment, (2) systemic therapy (ST), (3) cytoreductive nephrectomy (CNT), (4) CNT + ST. Kaplan-Meier plots and multivariable Cox regression analyses were used.

RESULTS

Of ccmRCC patients, 410 (7%), 4353 (75%), and 1005 (17%) were African-American, Caucasian, and Hispanic, respectively. Of non-ccmRCC patients, 183 (25%), 479 (65%), and 77 (10%) were African-American, Caucasian, and Hispanic, respectively. In ccmRCC, African-Americans were associated with higher OM rates (HR 1.20; 95% CI 1.05-1.37). Conversely, in non-ccmRCC, African-Americans were associated with lower OM rates (HR 0.75; 95% CI 0.59-0.97).

CONCLUSION

African-American race is associated with prolonged survival in non-ccmRCC, but it is also associated with lower survival rates in ccmRCC. The exception to these observations consisted of patients treated with combination of CNT + ST for either ccmRCC or non-ccmRCC.

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

PURPOSE

Renal cell carcinoma (RCC) incidence is higher among black than white Americans. The reasons for this disparity remain unclear.

METHODS

We calculated race- and sex-specific population attributable risk percentages (PAR%) and their 95% confidence intervals (CI) for hypertension and chronic kidney disease (CKD) among black and white subjects ≥  50 years of age from the US Kidney Cancer Study (USKC; 965 cases, 953 controls), a case-control study in Chicago and Detroit, and a nested case-control study in the Kaiser Permanente Northern California health care network (KPNC; 2,162 cases, 21,484 controls). We also estimated PAR% for other modifiable RCC risk factors (cigarette smoking, obesity) in USKC.

RESULTS

In USKC, the PAR% for hypertension was 50% (95% CI 24-77%) and 44% (95% CI 25-64%) among black women and men, respectively, and 29% (95% CI 13-44%) and 27% (95% CI 14-39%) for white women and men, respectively. In KPNC, the hypertension PAR% was 40% (95% CI 18-62%) and 23% (95% CI 2-44%) among black women and men, and 27% (95% CI 20-35%) and 19% (95% CI 14-24%) among white women and men, respectively. The PAR% for CKD in both studies ranged from 7 to 10% for black women and men but was negligible (<1%) for white subjects. In USKC, the PAR% for current smoking was 20% and 8% among black and white men, respectively, and negligible and 8.6% for black and white women, respectively. The obesity PAR% ranged from 12 to 24% across all race/sex strata.

CONCLUSIONS

If the associations found are causal, interventions that prevent hypertension and CKD among black Americans could potentially eliminate the racial disparity in RCC incidence (hypothetical black:white RCC incidence ratio of 0.5).

Epidemiology and Risk Factors for Kidney Cancer

The purpose of this narrative review is to summarize evidence of the epidemiology of and risk factors for kidney cancer with a focus on renal cell carcinoma in adults. The etiology of kidney cancer is largely unknown and the main epidemiologic determinants are large geographic and temporal variations in incidence rates. Established risk factors include tobacco smoking, body size, and history of hypertension and chronic kidney disease. Other suspected risk factors require additional investigation, as do the underlying biologic mechanisms that are responsible for disease occurrence. Opportunities to prevent kidney cancer include targeting modifiable risk factors-for example, smoking abstinence/cessation and body weight control-as well as interventions along the diagnostic pathway to improve early diagnosis. Molecular epidemiology, including, but not limited to, metabolomics and tumor genomics, are new areas of research that promise to play important roles in identifying some of the underlying causes of kidney cancer.

Ethnic disparities in renal cell carcinoma: An analysis of Hispanic patients in a single-payer healthcare system

OBJECTIVE

To investigate differences between Hispanics and non-Hispanic whites diagnosed with and treated for renal cell carcinoma in an equal access healthcare system.

METHODS

We carried out a retrospective cohort study within the Kaiser Permanente healthcare system using records from renal cell carcinoma cases. Ethnicity was identified as Hispanic or non-Hispanic whites. Patient characteristics, comorbidities, tumor characteristics and treatment were compared. Overall and disease-specific survival was calculated, and a Cox proportion hazard model estimated the association of ethnicity and survival.

RESULTS

A total of 2577 patients (2152 non-Hispanic whites, 425 Hispanic) were evaluated. Hispanics were diagnosed at a younger age (59.6 years vs 65.3 years). Clear cell renal cell carcinoma was more prevalent, whereas papillary renal cell carcinoma was less common among Hispanics. Hispanics had a lower American Joint Committee on Cancer stage (I/II vs III/IV) than non-Hispanic whites (67.4% vs 62.2%). Hispanics were found to have a greater frequency of comorbidities, such as chronic kidney disease and diabetes, but were more likely to receive surgery. The presence of metastases, nodal involvement, increased tumor size, non-surgical management, increasing age and Hispanic ethnicity were independent predictors of worse cancer-specific outcome.

CONCLUSIONS

Within an equal access healthcare system, Hispanics seem to be diagnosed at younger ages, to have greater comorbidities and to present more frequently with clear cell renal cell carcinoma compared with non-Hispanic white patients. Despite lower stage and greater receipt of surgery, Hispanic ethnicity seems to be an independent predictor of mortality. Further work is necessary to confirm these findings.

Logistic Bayesian LASSO for genetic association analysis of data from complex sampling designs

Detecting gene-environment interactions with rare variants is critical in dissecting the etiology of common diseases. Interactions with rare haplotype variants (rHTVs) are of particular interest. At the same time, complex sampling designs, such as stratified random sampling, are becoming increasingly popular for designing case-control studies, especially for recruiting controls. The US Kidney Cancer Study (KCS) is an example, wherein all available cases were included while the controls at each site were randomly selected from the population by frequency matching with cases based on age, sex and race. There is currently no rHTV association method that can account for such a complex sampling design. To fill this gap, we consider logistic Bayesian LASSO (LBL), an existing rHTV approach for case-control data, and show that its model can easily accommodate the complex sampling design. We study two extensions that include stratifying variables either as main effects only or with additional modeling of their interactions with haplotypes. We conduct extensive simulation studies to compare the complex sampling methods with the original LBL methods. We find that, when there is no interaction between haplotype and stratifying variables, both extensions perform well while the original LBL methods lead to inflated type I error rates. However, when such an interaction exists, it is necessary to include the interaction effect in the model to control the type I error rate. Finally, we analyze the KCS data and find a significant interaction between (current) smoking and a specific rHTV in the N-acetyltransferase 2 gene.

Predictors of growth kinetics and outcomes in small renal masses (SRM ≤4 cm in size): Tayside Active Surveillance Cohort (TASC) Study

OBJECTIVE

To determine outcomes of small renal masses (≤4 cm) on active surveillance and explore factors which can influence their growth.

PATIENTS AND METHODS

Two hundred twenty six patients between January 2007 and December 2014 were analysed using cross-linked methodology of healthcare data and independent review. Cancer specific and non-specific survival were the primary outcomes. Growth kinetics, factors influencing growth and need for interventions were secondary outcomes.

RESULTS

101 (64.4%) solid and 4 (5.9%) cystic SRMs showed growth. 43 (19.02%) of SRMs required treatment interventions. Seven patients (7/158; 4.4%) died due to renal cancer at a median follow-up of 21.7 (SD 10.6, min 6-42) months, all in solid category. Independent review of serial radiological imaging of these seven cases showed two patients had subtle metastatic disease at the initial presentation, and 5 of the 7 did not adhere to recommended imaging regime. 33 (33/158; 20.8%) died due to other causes including non-renal cancers (14/158; 8.8%). Multivariate analyses showed that lower eGFR at baseline, co-morbidities and tumour location were independently associated with growth in size.

CONCLUSIONS

A higher cancer-specific mortality was seen in the present study compared to the reported literature. Independent critical review of imaging of cases with poor outcome underscored the importance of adherence to a robust protocol including follow up. Comorbid conditions had a significant impact on growth and overall survival of patients with SRMs.

Review of renal cell carcinoma and its common subtypes in radiology

Representing 2%-3% of adult cancers, renal cell carcinoma (RCC) accounts for 90% of renal malignancies and is the most lethal neoplasm of the urologic system. Over the last 65 years, the incidence of RCC has increased at a rate of 2% per year. The increased incidence is at least partly due to improved tumor detection secondary to greater availability of high-resolution cross-sectional imaging modalities over the last few decades. Most RCCs are asymptomatic at discovery and are detected as unexpected findings on imaging performed for unrelated clinical indications. The 2004 World Health Organization Classification of adult renal tumors stratifies RCC into several distinct histologic subtypes of which clear cell, papillary and chromophobe tumors account for 70%, 10%-15%, and 5%, respectively. Knowledge of the RCC subtype is important because the various subtypes are associated with different biologic behavior, prognosis and treatment options. Furthermore, the common RCC subtypes can often be discriminated non-invasively based on gross morphologic imaging appearances, signal intensity on T2-weighted magnetic resonance images, and the degree of tumor enhancement on dynamic contrast-enhanced computed tomography or magnetic resonance imaging examinations. In this article, we review the incidence and survival data, risk factors, clinical and biochemical findings, imaging findings, staging, differential diagnosis, management options and post-treatment follow-up of RCC, with attention focused on the common subtypes.

Racial disparities in renal cell carcinoma: a single-payer healthcare experience

Significant racial disparities in survival for renal cell carcinoma (RCC) exist between white and black patients. Differences in access to care and comorbidities are possible contributors. To investigate if racial disparities persist when controlling for access to care, we analyzed data from a single-payer healthcare system. As part of a case-control study within the Kaiser Permanente Northern California system, pathologic and clinical records were obtained for RCC cases (2152 white, 293 black) diagnosed from 1998 to 2008. Patient demographics, comorbidities, tumor characteristics, and treatment status were compared. Overall survival and disease-specific survival (DSS) were calculated by the Kaplan-Meier method. A Cox proportion hazards model estimated the independent associations of race, comorbidity, and clinicopathologic variables with DSS. We found that compared to white patients, black patients were diagnosed at a younger age (median 62 vs. 66 years, P < 0.001), were more likely to have papillary RCC (15% vs. 5.2%, P < 0.001), and had similar rates of surgical treatment (78.8% vs. 77.9%, P = 0.764). On multivariate analysis, advanced American Joint Committee on Cancer (AJCC) stage, lack of surgical treatment, larger tumor size, and higher grade were predictors of worse DSS. Race was not an independent predictor of survival. Therefore, we conclude that within a single healthcare system, differences in characteristics of black and white patients with RCC persist; black patients had different comorbidities, were younger, and had decreased tumor stage. However, unlike other series, race was not an independent predictor of DSS, suggesting that survival differences in large registries may result from barriers to healthcare access and/or comorbidity rather than disease biology.

Does beer, wine or liquor consumption correlate with the risk of renal cell carcinoma? A dose-response meta-analysis of prospective cohort studies

Despite plenty of evidence supports an inverse association between alcohol drinking and risk of renal cell carcinoma (RCC), sex-specific and beverage-specific dose-response relationships have not been well established. We examined this association by performing a systematic review and meta-analysis of prospective studies. Studies were identified by comprehensively searching PubMed and EMBASE databases through February 21, 2015. Categorical and dose-response meta-analyses were conducted to identify the effects of alcohol on RCC. A total of eight publications (including seven cohort studies and one pooled analysis of 12 cohort studies) were eligible for this meta-analysis. Dose-response analysis showed that each 5 g/day increment of alcohol intake corresponded to a 5% decrease in risk of RCC for males and 9% for females. Alcohol intakes from wine, beer, and liquor were each associated with a reduced risk of RCC. When these associations were examined separately by gender, statistically significant inverse associations were restricted to alcohol from wine among females (RR = 0.82, 95% CI 0.73–0.91) and to alcohol from beer and from liquor among males (RR = 0.87, 95% CI 0.83–0.91 and RR = 0.95, 95% CI 0.92–0.99, respectively). In conclusion, there exist gender-specific and beverage-specific differences in the association between alcohol intake and RCC risk.

Racial disparities in overall survival among renal cell carcinoma patients with young age and small tumors

We examined the overall survival of a population‐based cohort of black and white patients with renal cell carcinoma (RCC) to better understand the paradox of poorer RCC survival despite more frequent diagnosis at lower stage among blacks. Renal cell carcinoma patients (699 white, 252 black) diagnosed between 2002 and 2007 in metropolitan Detroit were followed for vital status in the Detroit Surveillance, Epidemiology and End Results (SEER) registry. Hazard ratios (HR) of death for black versus white race and 95% confidence intervals (CIs) were calculated using Cox proportional hazard models stratified by demographic and prognostic factors, and in models successively adjusted for clinical factors, comorbidities, and socioeconomic factors. Mean follow‐up time was 88.4 months for white patients and 89.6 months for black patients (P = 0.49), with 202 white deaths and 89 black deaths (P = 0.06). While black race was weakly associated with poorer overall survival (P = 0.053), black patients <65 years at diagnosis or with tumors <4 cm in size had significantly poorer survival than their white counterparts (HR = 1.46, 95% CI 1.06–2.01 and HR = 2.15, 95% CI 1.51–3.06, respectively). The racial disparities within these two subgroups were minimally affected by adjustment for clinical/treatment factors (HR = 1.49, 95% CI 1.01–2.19 and HR = 1.95, 95% CI 1.27–2.99), but were substantially reduced when renal‐relevant comorbidities were added (HR = 1.30, 95% CI 0.89–1.91 and HR = 1.76, 95% CI 1.16–2.66). After further adjustment for socioeconomic factors, the survival disparities were essentially null (HR = 1.14, 95% CI 0.71–1.85 and HR = 1.15, 95% CI 0.67–1.98). In this population‐based sample of RCC patients, younger black patients and those with small tumors had poorer overall survival than whites. The disparity was explained primarily by racial differences in renal‐relevant comorbidities, particularly chronic renal failure, and socioeconomic deprivation. Future research should focus on younger patients and those with smaller tumors to better understand how these factors may contribute to the survival disparity.

Geographic Variation of Chronic Kidney Disease Prevalence: Correlation with the Incidence of Renal Cell Carcinoma or Urothelial Carcinoma?

Background. The aim of this study is to evaluate whether geographic variations in the prevalence of late-stage chronic kidney disease (CKD) exist and are associated with incidence rates of renal cell carcinoma (RCC), upper tract urothelial carcinoma (UTUC), or lower tract urothelial carcinoma (LTUC). Methods. Prevalence rates of late-stage CKD for 366 townships (n > 30) in Taiwan were calculated for 1,518,241 and 1,645,151 subjects aged 40 years or older in years 2010 and 2009, respectively. Late-stage CKD prevalence in year 2010 was used as a training set and its age-adjusted standardized morbidity rates (ASMR) were divided into three groups as defined <1.76%, 1.76% ≤ ASMR < 2.64%, and ≥2.64%, respectively. Year 2009, defined as the validation set, was used to validate the results. Results. The ASMR of late-stage CKD in years 2010 and 2009 were 1.76%, and 2.09%, respectively. Geographic variations were observed, with notably higher rates of disease in areas of the central, southwestern mountainside, and southeastern seaboard. There were no significant differences among different combined risk groups of RCC, UTUC, and LTUC incidence. Conclusion. The substantial geographic variations in the prevalence of late-stage CKD exist, but are not correlated with RCC, UTUC, or LTUC incidence.

Chronic kidney disease and risk of renal cell carcinoma: differences by race

BACKGROUND

The incidence of renal cell carcinoma in the United States differs by race/ethnicity. To better understand these disparities, we conducted a nested case-control study investigating renal cell carcinoma risk factors across racial/ethnic groups within the Kaiser Permanente Northern California health care network.

METHODS

Our study included 3136 renal cell carcinoma cases (2152 whites, 293 blacks, 425 Hispanics, and 255 Asians) diagnosed between 1998 and 2008 and 31031 individually matched controls (21478 whites, 2836 blacks, 4147 Hispanics, and 2484 Asians). Risk of renal cell carcinoma was assessed in relation to smoking status, body mass index (BMI), hypertension, and chronic kidney disease. We calculated odds ratios (ORs) and 95% confidence intervals (CIs) using conditional logistic regression, and population attributable risk (PAR) to estimate by race the proportion of cases attributable to hypertension and chronic kidney disease.

RESULTS

The association between chronic kidney disease and renal cell carcinoma differed markedly by race (Pinteraction < 0.001), with associations observed among blacks (OR = 10.4 [95% CI = 6.0-17.9]), Asians (5.1 [2.2-11.7]), and Hispanics (2.3 [1.1-4.6]) but not whites (1.1 [0.6-1.9]). Hypertension, high BMI, and smoking were associated with renal cell carcinoma, but findings generally did not differ by race. Relative to other racial/ethnic groups, blacks had the highest proportion of renal cell carcinoma incidence attributable to hypertension and chronic kidney disease (combined, PAR = 37%; hypertension only, PAR = 27%; chronic kidney disease, PAR = 10%).

CONCLUSIONS

Our findings suggest that hypertension and chronic kidney disease likely have contributed to the observed excess in renal cell carcinoma incidence among blacks compared with whites.

Survival among Black and White patients with renal cell carcinoma in an equal-access health care system

PURPOSE

Unequal access to health care may be a reason for shorter survival among Black patients with renal cell carcinoma (RCC) than among their White counterparts. No studies have investigated survival disparity among RCC patients in an equal-access health care delivery system. This study aimed to examine racial differences in survival among clear cell RCC patients in the Department of Defense's (DoD) Military Health System (MHS), which provides equal access to care to all persons.

METHODS

The study used the DoD's Automated Central Tumor Registry to identify 2056 White patients and 370 Black patients diagnosed with clear cell RCC between 1988 and 2004. The subjects were followed through 2007 with a median follow-up time of 4.8 years. Kaplan-Meier survival curves were compared and a Cox model was used to estimate the hazard ratios (HRs) associated with survival by race.

RESULTS

During follow-up, 1,027 White and 158 Black patients died. The Kaplan-Meier curves showed that Black patients had more favorable overall survival than did White patients (log rank p = 0.031). After adjustment for demographic, tumor, and treatment variables, the Cox model showed no statistically significant racial difference overall (adjusted HR 1.07, 95 % CI 0.90-1.28) or stratified by age, sex or tumor stage. However, among patients who did not undergo surgery, Black patients had poorer survival than White patients.

CONCLUSIONS

The lack of racial difference in survival among RCC patients in the MHS may be related to equal access to health care. Improved access could reduce the survival disparity among RCC patients in the general population.

Physical activity and renal cell carcinoma among black and white Americans: a case-control study

Background

Renal cell carcinoma (RCC) has a higher incidence in blacks than in whites. Physical activity may influence the risk of renal cell cancer, but the evidence is inconsistent. No previous study has investigated this relationship in the black population.

Methods

We examined the association between self-reported physical activity at different ages and risk of RCC in a population based case-control study of 1217 cases (361 black, 856 white) and 1235 controls (523 black, 712 white) frequency-matched on age, race, and gender. Multivariate-adjusted odds ratios (OR) and 95% confidence intervals (CI) were estimated using unconditional logistic regression.

Results

Among whites, increased risks of RCC were observed among participants reporting low levels of transportation-related activity in their 20’s (OR _{<1 hr/wk vs >7 hr/wk} (95% CI): 1.42 (1.10, 1.83)) and leisure time activity in their 50’s (OR _{<1 hr/wk vs >7 hr/wk} (95% CI): 1.49 (1.00, 2.20)). We found no association between physical activity and RCC risk among blacks.

Conclusion

Our results suggest that physical activity may be inversely associated with RCC risk in whites, but there was no evidence of such an association in blacks. As this is the first study evaluating the effect of physical activity on RCC risk among blacks, further investigations are needed to clarify the relationship in this population.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2407-14-707) contains supplementary material, which is available to authorized users.

Renal insufficiency is associated with an increased risk of papillary renal cell carcinoma histology

PURPOSE

End-stage renal disease (ESRD) and acquired renal cystic disease associated with dialysis are known risk factors of papillary renal cell carcinoma (pRCC); however, it is not known whether renal insufficiency alone is a risk factor for pRCC. Our aim was to test whether renal insufficiency is associated with an increased preponderance of pRCC.

METHODS

Retrospective review of institutional database to identify all patients who underwent extirpative renal surgery for renal cell carcinoma (RCC) with complete records from 1992 to 2012. We excluded those patients with preoperative ESRD as defined by GFR < 15 mL/min/1.73 m(2). The dependent variable was histologic RCC subtype. Independent variables included demographic data, comorbidities, and renal functional data. Multivariate analysis by binary logistic regression was used to determine factors that independently were associated with pRCC development.

RESULTS

A total of 1,226 patients met inclusion criteria, of which 15 % were pRCC. There was a positive association between likelihood of pRCC histology of RCC and increasing preoperative chronic kidney disease (CKD) stage (p = 0.021). Multivariate regression analysis indicated that male gender, race, and declining renal function categorized both by GFR and CKD stage were independently associated with a higher likelihood of pRCC histology as compared to other RCC histology.

CONCLUSIONS

Within a large cohort of patients with a diagnosis of RCC, declining renal function was independently associated with an increased likelihood of pRCC histology. This finding and the available molecular evidence indicating protein expression similarity between pRCC and resident stem cells, which appear to be upregulated with kidney damage, suggest a possible causal relationship between renal injury and pRCC.