Obesity and renal cell carcinoma: epidemiology, underlying mechanisms and management considerations

Therapeutic strategies and predictive models for Xp11.2 translocation/TFE3 gene fusion renal cell carcinoma in adults based on data of two Chinese medical centers

OBJECTIVE

This study aims to establish an effective predictive model for predicting Xp11.2 translocation/TFE3 gene fusion renal cell carcinoma (TFE3-RCC) and develop optimal therapeutic strategies.

METHODS

Data from 4961 patients diagnosed with renal cell carcinoma at two medical centers in China were retrospectively analyzed. A cohort of 1571 patients from Zhejiang Provincial People's Hospital (Ra cohort) was selected to construct the model. Another cohort of 1124 patients from the Second Affiliated Hospital of Zhejiang Chinese Medical University was used for external validation (the Ha cohort). All patients with TFE3-RCC in both cohorts were included in the Ta cohort for the prognostic analysis. Univariate and multivariate binary logistic regression analyses were performed to identify independent predictors of the predictive nomogram. The apparent performance of the model was validated. Decision curve analysis was also performed to assess the clinical utility of the developed model. Factors associated with progression and prognosis in the Ta cohort were analyzed using the log-rank method, and Cox regression analysis and Kaplan-Meier survival curves were used to describe the effects of factors on prognosis and progression.

RESULTS

Univariate and multivariate logistic regression analyses demonstrated that age, sex, BMI, smoking, eosinophils, and LDL were independent predictors of TFE3-RCC. Therefore, a predictive nomogram for TFE3-RCC, which had good discriminatory power (AUC = 0.796), was constructed. External validation (AUC = 0.806) also revealed good predictive ability. The calibration curves displayed good consistency between the predicted and observed incidences of TFE3-RCC. Invasion of regional lymph nodes, tyrosine kinase inhibitors, and surgical methods were independent factors associated with progression. Tyrosine kinase inhibitors are independent prognostic factors.

CONCLUSION

This study not only proposed a high-precision clinical prediction model composed of various variables for the early diagnosis of Xp11.2 translocation/TFE3 gene fusion renal cell carcinoma but also optimized therapeutic strategies through prognostic analysis.

Hsa_circ_0003596 enhances the development of cell renal clear cell carcinoma through the miR-502-5p/IGF1/PI3K/AKT axis

Accumulating research findings have shown that circular RNAs (circRNAs) play an indispensable role in tumorigenesis and tumor progression. The current study aimed to explore the role and modulatory mechanism of hsa_circ_0003596 in clear cell renal cell carcinoma (ccRCC). Quantitative real-time polymerase chain reaction was adopted to detect the expression of hsa_circ_0003596 in ccRCC tissue and cell lines. 5-Ethynyl-2'-deoxyuridine, cell counting kit 8 and the colony formation assay were utilized to assess the proliferation potential of the ccRCC cells. Transwell along with wound healing assays were adopted to quantify infiltration coupled with the migration potential of the cells. The current research study found that the circRNA hsa_circ_0003596 was overexpressed in ccRCC tissue and cell lines. Further, result showed that hsa_circ_0003596 was associated with distant metastasis of renal cancer. Notably, the knockdown of hsa_circ_0003596 can lower the proliferation, infiltration and migration potential of ccRCC cells. The results of in vivo experiments found that the reduction of hsa_circ_0003596 significantly hampered the growth of tumors in mice. In addition, it was evident that hsa_circ_0003596 acts as a "molecular sponge" for miR-502-5p to upregulate the expression of the microRNA-502-5p (miR-502-5p) target insulin-like growth factor 1 (IGF1R). Furthermore, it was found that the phosphatidylinositol 3-kinase (PI3K)/AKT signaling was the downstream cascade of hsa_circ_0003596/miR-502-5p/IGF1R cascade, which is partly responsible for the cancer-promoting effect. Overall, the results of the present study showed that hsa_circ_0003596 facilitated the proliferation, infiltration and migration of ccRCC through the miR-502-5p/IGF1R/PI3K/AKT axis. Therefore, it was evident that hsa_circ_0003596 can serve as a possible biomarker and therapeutic target against ccRCC.

Tivozanib for the treatment of advanced renal cell carcinoma

INTRODUCTION

Renal cell carcinoma (RCC) accounts for 2.4% of cancers, with clear cell kidney cancer being the most common histologic subtype. Despite recent therapeutic advances, the prognosis for patients with advanced disease remains poor, with a 5-year survival rate of only 13.9% reported in the United States. Tivozanib is a novel inhibitor of vascular endothelial growth factor (VEGF) receptor (VEGFR) -1, -2, and -3 and has recently been approved by the US FDA for use in patients with relapsed or recurrent advanced RCC following 2 or more prior systemic therapies.

AREAS COVERED

Here, the authors provide a review focusing on the development of tivozanib, compare tivozanib to other agents in the VEGFR inhibitor class, detail how tivozanib fits into current treatment landscape, and describe ongoing studies involving this agent.

EXPERT OPINION

Given tivozanib's excellent safety profile and demonstrated clinical benefit in patients with pretreated disease, tivozanib is likely to be heavily utilized in the later line setting. The ongoing TINIVO-2 study may further impact the treatment landscape by evaluating the use of tivozanib plus nivolumab in patients who have progressed on an immune checkpoint inhibitor.

Renal Cell Cancer and Obesity

Cancers are a frequent cause of morbidity and mortality. There are many risk factors for tumours, including advanced age, personal or family history of cancer, some types of viral infections, exposure to radiation and some chemicals, smoking and alcohol consumption, as well as obesity. Increasing evidence suggest the role of obesity in the initiation and progression of various cancers, including renal cell carcinoma. Since tumours require energy for their uncontrollable growth, it appears plausible that their initiation and development is associated with the dysregulation of cells metabolism. Thus, any state characterised by an intake of excessive energy and nutrients may favour the development of various cancers. There are many factors that promote the development of renal cell carcinoma, including hypoxia, inflammation, insulin resistance, excessive adipose tissue and adipokines and others. There are also many obesity-related alterations in genes expression, including DNA methylation, single nucleotide polymorphisms, histone modification and miRNAs that can promote renal carcinogenesis. This review focuses on the impact of obesity on the risk of renal cancers development, their aggressiveness and patients’ survival.

Risk Factors for the Comorbidity of Hypertension and Renal Cell Carcinoma in the Cardio-Oncologic Era and Treatment for Tumor-Induced Hypertension

Advances in tumor diagnosis and treatment, especially the use of targeted therapies, have remarkably improved the survival rate of patients with renal cell carcinoma (RCC), accompanied by higher hypertension (HTN) incidence among patients with RCC, reflecting the coming of a cardio-oncologic era. Therefore, for patients with RCC and HTN simultaneously, finding risk factors for the comorbidity and giving better clinical treatment have been urgent problems. In this review, we thoroughly investigated risk factors for the comorbidity of HTN and RCC based on preclinical and clinical studies. Firstly, RCC and HTN may have common risk factors, such as obesity, smoking, and other modifiable lifestyles. Secondly, RCC and HTN may lead to each other directly or indirectly by their therapies. We then discussed measures of reducing the comorbidity and treatment of HTN in patients with RCC. We also discussed the deficiency of current studies and pointed out future directions. In conclusion, this review aims to deepen the understanding of cardio-oncology and bring benefit to the population who are at high risk of getting or have already got RCC and HTN simultaneously.

Short-Term and Long-Term Renal Outcomes in Patients With Obesity After Minimally Invasive Versus Open Partial Nephrectomy for the Treatment of Renal Cancer: Retrospective Study

Background

Obesity is significantly associated with renal cell carcinoma. Surgery is the preferred treatment for demarcated lesions of renal cell carcinoma; however, obesity increases the complexity of surgical outcomes. Minimally invasive surgical techniques are preferred over open partial nephrectomy (OPN), but controversy remains regarding the most efficacious technique in patients with obesity.

Objective

This study aims to determine whether minimally invasive partial nephrectomy (MIPN) or OPN better preserves renal function and investigate short- and long-term renal outcomes in patients with obesity undergoing a partial nephrectomy.

Methods

We conducted a retrospective chart review of 242 adult patients aged ≥18 years who underwent MIPN or OPN between January 1, 2005, and December 31, 2016, at the University of Arkansas for Medical Sciences. Using creatinine as a measure of kidney function, patients’ preoperative levels were compared with their postoperative levels in 2-time frames: short (3-6 months postsurgery) or long (>6 months). The primary outcome was the change in creatinine values from preoperative to >6 months postoperatively in patients with obesity. Secondary outcomes included the change in creatinine values from preoperative to 3 to 6 months postoperatively in patients with obesity who underwent MIPN versus OPN. We also analyzed the creatinine values of nonobese patients (BMI <30) who underwent partial nephrectomy using the same time frames. Unconditional logistic regression was used to estimate crude and multivariable-adjusted odds ratios (ORs) and 95% CI to observe associations between surgery type and changes in creatinine values from while stratifying for obesity.

Results

A total of 140 patients were included in the study, of whom 75 were obese and 65 were nonobese. At >6 months after MIPN (n=20), the odds of patients with obesity having a decrease or no change in creatinine values was 1.24 times higher than those who had OPN (n=13; OR 1.24, 95% CI 0.299-6.729; P=.80). At 3 to 6 months after MIPN (n=27), the odds were 0.62 times lower than those after OPN (n=17; OR 0.62, 95% CI 0.140-2.753; P=.56). In the nonobese group, at 3 to 6 months after undergoing minimally invasive surgery (n=18), the odds of having a decrease or no change in creatinine values was 4.86 times higher than those who had open surgery (n=21; OR 4.86, 95% CI 1.085-21.809; P=.04). At more than 6 months after MIPN (n=14), the odds were 4.13 times higher than those after OPN (n=11; OR 4.13, 95% CI 0.579-29.485; P=.16).

Conclusions

We observed a nonstatistically significant preservation of renal function in patients with obesity who underwent OPN at 3 to 6 months postoperatively. Conversely, after 6 months, the same was true for MIPN, indicating the long-term benefit of MIPN. In the nonobese group, MIPN was favored over OPN. 

Differences in risk factors for molecular subtypes of clear cell renal cell carcinoma

The ccA and ccB molecular subtypes of clear cell renal cell carcinoma (ccRCC) have well-characterized prognostic relevance. However, it is not known whether they possess distinct etiologies. We investigated the relationships between these subtypes and RCC risk factors within a case-control study conducted in Eastern Europe. We analyzed risk factor data for ccA (n = 144) and ccB (n = 106) cases and 1476 controls through case-only and case-control comparisons to assess risk factor differences across subtypes using logistic and polytomous regression models. We also performed a meta-analysis summarizing case-only results from our study and three patient cohorts. Patients with ccB tumors had poorer survival than those with ccA tumors and were more likely to be male (case-only odds ratio [OR] 2.68, 95% confidence interval [CI] 1.43-5.03). In case-control analyses, body mass index was significantly associated with ccA tumors (OR 2.45, 95% CI 1.18-5.10 for ≥35 vs <25 kg/m2 ) but not with ccB tumors (1.52, 0.56-4.12), while trichloroethylene was associated with ccB but not ccA (OR 3.09, 95% CI 1.11-8.65 and 1.25, 0.36-4.39 respectively for ≥1.58 ppm-years vs unexposed). A polygenic risk score of genetic variants identified from genome-wide association studies was associated with both ccA and, in particular, ccB (OR 1.82, 1.11-2.99 and 2.87, 95% CI 1.64-5.01 respectively for 90th vs 10th percentile). In a meta-analysis of case-only results including three patient cohorts, we still observed the ccB excess for male sex and the ccA excess for obesity. In conclusion, our findings suggest the existence of etiologic heterogeneity across ccRCC molecular subtypes for several risk factors.

Perioperative impact of body mass index on upper urinary tract and renal robot-assisted surgery: a single high-volume centre experience

To assess the impact of body mass index (BMI) on peri-operative outcomes of kidney and upper tract robot-assisted surgery. Medical audit of patients who underwent robot-assisted kidney and upper tract cancer surgery at a single institution between 2017 and 2019, categorized on BMI into obese patients with a BMI ≥ 30 kg/m² and a control group with BMI < 25 kg/m². Patient and tumour characteristics, surgery time, intraoperative blood loss, intraoperative adverse events (AE) according to the European Association of Urology Intraoperative Adverse Incidents Classification (EAUiaiC), conversion- to-open/radical rate as well as 30-day postoperative AE according to Clavien-Dindo (CD) and length of inpatient stay were analyzed. 366 patients were identified, 141 with a BMI < 25 (normal-weight) and 225 BMI ≥ 30 (obesity). There were no significant differences between the groups in terms of age, gender, comorbidities, tumour size, TNM stage and type of surgery. Obese patients had a higher estimated blood loss (198.05 ml), surgery time (171.75 min), intraoperative AE (all grades) (14.67%, 95% CI (0.10-0.19) as well as adherent perinephric fat (APF) (14.22%, 95% CI (0.09-0.19)) in contrast to the control group (86.85 ml, 148.29 min, 7.04% and 2.12%, respectively). Hospital stay, major intraoperative AE (≥ 3) and major postoperative AE (CD > 2) distributed equally between groups. Robotic kidney and upper tract surgery in obese patients showed an increase in surgery time and blood loss potentially related to APF. However, obesity was not associated with conversion to open surgery or radical nephrectomy in nephron-sparing procedures, length of stay, major intraoperative AE or postoperative complications.

Adaptive Magnetic Resonance-Guided Stereotactic Body Radiotherapy: The Next Step in the Treatment of Renal Cell Carcinoma

Adaptive MR-guided radiotherapy (MRgRT) is a new treatment paradigm and its role as a non-invasive treatment option for renal cell carcinoma is evolving. The early clinical experience to date shows that real-time plan adaptation based on the daily MRI anatomy can lead to improved target coverage and normal tissue sparing. Continued technological innovations will further mitigate the challenges of organ motion and enable more advanced treatment adaptation, and potentially lead to enhanced oncologic outcomes and preservation of renal function. Future applications look promising to make a positive clinical impact and further the personalization of radiotherapy in the management of renal cell carcinoma.

Patient-reported Quality of Life following Stereotactic Body Radiation Therapy for Primary Kidney Cancer - Results from a Prospective Cohort Study

AIMS

We report on the first prospective series of patient-reported quality of life (QoL) following stereotactic body radiation therapy (SBRT) for primary kidney cancer.

MATERIALS AND METHODS

Patients were treated on a multi-institutional prospective cohort study with 30-42 Gy SBRT in three or five fractions. QoL assessments were carried out using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core-15 Palliative (EORTC-QLQ-C15-PAL), the Functional Assessment of Cancer Therapy-Kidney Symptom Index-19 (FACT FKSI-19) and the EuroQol-5D-3L tools at baseline, 1 week, and 1, 3 and 6 months post-treatment. QoL over time was analysed using linear mixed modelling, pairwise and anchor-based analyses.

RESULTS

Twenty-eight patients were included. No significant reduction in any QoL metric was observed on repeated measures. However, a trend to reduced EORTC global QoL and fatigue was observed at 1 week, with improvement over time in other symptom scores such as pain, appetite and nausea. On pairwise analysis, there were statistically significant reductions in global QoL at 1 week (with subsequent recovery) and dyspnoea at 6 months post-SBRT. Trends to improved pain, appetite and nausea were observed following SBRT. Less than half of patients reported stable or better EORTC global QoL at 1 week. For all other QoL and symptom scales, most patients had reported stable or better scores at all times, with a slight proportional improvement in emotional functioning, nausea, fatigue, pain and appetite, and a slight worsening of physical functioning and dyspnoea over time.

CONCLUSIONS

SBRT results in well-preserved QoL in the weeks to months following treatment for primary kidney cancer.

A Study on the Immunohistochemical Expressions of Leptin and Leptin Receptor in Clear Cell Renal Cell Carcinoma

Background

The mechanisms that link obesity and cancer development are not well-defined. Investigation of leptin and leptin receptor expressions may help define some of the mechanisms. These proteins are known for associating with the immune response, angiogenesis and, signalling pathways such as JAK2/STAT3, PI3K, and AKT pathways. Tissue proteins can be easily detected with immunohistochemistry (IHC), a technique widely used both in diagnostic and research laboratories. The identification of altered levels of leptin and leptin receptor proteins in tumour tissues may lead to targeted treatment for cancer.

Objective

The objective of this study was to use IHC to compare leptin and leptin receptor expressions in clear cell renal cell carcinomas (ccRCC) in non-obese and obese patients to determine the association between these proteins with the clinicopathological features and prognosis of ccRCC. Patients and Methods. The study involved 60 patients who underwent nephrectomy of which 34 were obese, as assessed using body mass index (BMI). Nephrectomy samples provided tissues of ccRCC and adjacent non-cancerous kidney. The intensity and localization of leptin and leptin receptor protein expressions were evaluated using IHC and correlated with clinicopathological features and clinical outcomes. Aperio ImageScope morphometry and digital pathology were applied to assess the IHC results. The chi-square test was used to determine if there was any significant association between the proteins and the clinicopathological features. The Kaplan-Meier test was used to determine the overall survival, disease-free survival, and recurrence-free survival. A value of p < 0.05 was considered significant.

Results

There was neither significant difference in the overall cellular and nuclear expressions of leptin and leptin receptor between non-cancerous kidney and ccRCC tissues nor in non-obese and obese individuals with ccRCC.

Conclusion

In this present study, it was revealed that leptin and leptin receptor were not associated with tumour characteristics and progression of ccRCC patients. Interestingly, nuclear expression of leptin was significantly associated with overall survival. However, the significance of these proteins as biomarkers in other RCC histotypes is still unclear.

Role of leptin as a biomarker for early detection of renal cell carcinoma? No evidence from a systematic review and meta-analysis

Renal cell carcinoma (RCC) is the commonest from of renal neoplasm. Although surgery is a successful curative treatment for localized RCC, most patients are diagnosed with advanced or metastatic RCC, which has poor prognosis. RCC is classified by stage and grade using tissue samples. Whilst these provide good prognostic information, they are not very useful for early detection. Proteins that are dysregulated in patient's serum can be a valuable alternative and less invasive biomarker for early detection of the disease. For this reason, a hypothesis was formed that leptin is a possible biomarker for early detection and prognostication of RCC. The literature has disparate results on the usefulness of leptin as a biomarker for the early detection of RCC. Hence, a systematic review and a meta-analysis was carried out to investigate whether serum leptin could be a reliable diagnostic and prognostic factor in RCC patients. Literature on the available cohort and case-control studies on serum leptin in RCC was searched in electronic databases and included to evaluate this adipokine in the progression of RCC. The relevant studies were evaluated for the diagnostic and prognostic value of leptin in RCC patients. Overall, only 6 original research studies matched selection criteria and were included for meta-analysis. This study was hypothesised that; leptin might be a useful biomarker for early detection and prognostication of RCC. However, the data were presented in this study did not support our hypothesis. Serum leptin levels in RCC patients do not strongly associate with the development or progression of RCC, thus cannot act as a biomarker for early detection in RCC in patients. Extending our hypothesis further to include levels of obesity and RCC development may be worthwhile, but studies are currently limited.

Obesity, abdominal obesity and subsequent risk of kidney cancer: a cohort study of 23.3 million East Asians

Background

Limited evidence exists regarding associations between obesity and kidney cancer among Asians. We examined the associations between obesity measures and risk of kidney cancer.

Methods

We included 23,313,046 adults who underwent health examinations provided by the Korean National Health Insurance Service 2009–2012 and performed multivariable Cox proportional hazards regression analyses.

Results

During 5.4 years of follow-up, 18,036 cases of kidney cancer were recorded, and cumulative incidence was 0.12%. General and abdominal obesity were associated with 1.32-fold increased risk of kidney cancer compared with groups without either obesity status. Underweight individuals showed decreased adjusted hazard ratio (HR) for kidney cancer (0.76, 95% confidence interval: 0.68–0.85) compared to those with normal body mass index (BMI), while the HRs increased among individuals with BMI 23–24.9 kg/m² (1.23, 1.18–1.28), 25–29.9 kg/m² (1.41, 1.36–1.46) and ≥30 kg/m² (1.77, 1.65–1.90) (P for trend < 0.001). HRs of kidney cancer increased with increasing waist circumference (WC) (P for trend < 0.001). Compared to non-obese condition, the coexistence of general and abdominal obesity increased the HR (1.45, 1.40–1.50).

Conclusions

This study demonstrated positive associations of BMI and WC with kidney cancer risk. General and abdominal obesity may be risk factors of kidney cancer.

Prognostic biomarkers in renal cell carcinoma: is there a relationship with obesity?

Obesity is a recognized risk factor for renal cell carcinoma (RCC) the commonest form of kidney cancer. Both obesity and RCC are serious diseases with increasing incidence yearly. This review examined certain obesity associated measurements and adipokines as detection/prognostic indicators for RCC. The obesity related measurements such as body mass index (BMI), waist circumstance (WC), waist-hip ratio (WHR) in predicting RCC are valid when used in conjunction with other risk factors such as age and sex or with histological findings. The adipokine adiponectin holds promising outcomes as a predictive marker in assessing the risk of developing RCC. In addition, tissue leptin/leptin receptor may be a distinguishing marker for RCC subtypes. However, circulating leptin may not be a suitable detection or prognostic biomarker for RCC. The other less investigated adipokines; omentin, visfatin, apelin and resistin are also expressed in RCC but their prognostic capabilities are still inconclusive. BMI, WC and adipokines may be useful additions in a nomogram which includes TNM staging and pathological grading system to detect, confirm and follow-up RCC cases.

The impact of body mass index on perioperative outcomes after robotic liver resection

High body mass index (BMI) is associated with other multiple comorbidities such as non-alcoholic fatty liver disease, steatohepatitis, liver cirrhosis, and cardiopulmonary diseases, which can impact the perioperative outcomes following liver resection. We aimed to study the impact of BMI on perioperative outcomes after robotic liver resection. All the patients undergoing robotic liver resection between 2013 and 2017 were prospectively followed. The patients were divided into three groups (BMI < 25, BMI 25-35, BMI > 35 kg/m²) for illustrative purposes. Demographic and perioperative outcome data were compared. Data are presented as median (mean ± SD). Thirty-eight patients underwent robotic hepatectomy, 73% were women, age was 58 (57 ± 17.6) years, and ASA class was 3 (3 ± 0.5). Indications for surgery were neoplastic lesions in 34 patients (89%), hemangioma in two patients (6%), fibrous mass in one patient (2.5%), and focal nodular hyperplasia in one patient (2.5%). 32% of the patients underwent right or left hemihepatectomy, 21% underwent sectionectomy, 5% underwent central hepatectomy and the reminder underwent non-anatomical liver resection. Operative time was 261 (254.6 ± 94.3) min. Estimated blood loss was 175 (276 ± 294.8) ml. Length of hospital stay was 3 (5 ± 4.9) days. By regression analysis of the three BMI groups, estimated blood loss, rate of postoperative complication, rate of conversion, need for transfusion, length of ICU stay, and length of hospital stay did not have a significant relationship with BMI. A total of five patients (13%) experience complications. Four patients had complications that were nonspecific to liver resection, including acute renal injury, respiratory failure, and enterocutaneous fistula. One patient had bile leak, treated with ERCP stenting. No mortality was seen in this study. Obesity should not dissuade surgeons from utilizing minimally invasive robotic approach for liver resection. Robotic technique is a safe and feasible in patients with high BMI. The impact of BMI on outcomes is insignificant.

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.

Obesity and renal cell carcinoma risk by histologic subtype: A nested case-control study and meta-analysis

BACKGROUND

Although obesity is an established risk factor for renal cell carcinoma (RCC), it is unclear whether this relationship varies across histologic subtypes.

METHODS

We conducted a nested case-control study within the Kaiser Permanente Northern California (KPNC) health care network, and meta-analysis combining our results with those of previously published studies. Our KPNC study included 685 RCC cases [421 clear cell; 65 papillary; 24 chromophobe; 35 other; 141 not otherwise specified (NOS)] and 4266 controls. Subtype-specific odds ratios (ORs) and 95% confidence intervals (CIs) for categories of body mass index (BMI) and were computed from the case-control data using polytomous logistic regression. Findings from this and other relevant studies were combined by meta-analysis using a random effects model.

RESULTS

In the KPNC study, obesity (BMI ≥ 30 kg/m²) was associated with clear cell RCC (OR 1.5, 95% CI 1.1-2.1) and chromophobe RCC (OR 2.5, 95%CI 0.8-8.1), but not with papillary RCC (OR 1.0, 95% CI 0.5-1.9). In meta-analysis including three additional studies, a similar pattern of summary relative risks (SRR) for obesity was observed across subtypes (clear cell: SRR 1.8, 95% CI 1.5-2.2; chromophobe: SRR 2.2, 95% CI 1.3-3.7; papillary, SRR 1.2, 95% CI 0.8-1.6).

CONCLUSIONS

These findings support the hypothesis that histologic subtypes of RCC possess distinct etiologic pathways, with obesity important for the development of clear cell and, possibly, chromophobe RCC, but not papillary RCC.

Lifestyle Risk Factors in the Development of Kidney Cancer: A Russian Experience

The objective of our study was the evaluation of major lifestyle risk factors for the development of renal cell carcinoma (RCC) and the assessment of chances of developing this disease among inhabitants in the region, in the presence of and with combinations of the studied risk factors. Risk factors for developing RCC that are associated with lifestyle (smoking, obesity and hypertension) were observed in 500 patients with RCC aged 30-64 years who were investigated at the Krasnoyarsk Oncology Dispensary (study group) and 858 participants in the Krai (control group). The results of our study showed that smoking increases the risk of developing RCC 2.9 times and arterial hypertension 3.3 times in men; in women, obesity and hypertension increased these risks 2.6 and 3.2 times, respectively. All three risk factors were combined in 13.6% of men and in 8.4% of women with RCC. Our data may be useful for the prevention, development of screening programmes and early diagnosis of RCC.

TIKI2 is upregulated and plays an oncogenic role in renal cell carcinoma

TIKI2 is a negative regulator of the Wnt family. Although many Wnt antagonists play important roles in renal cell carcinoma (RCC), the molecular function of TIKI2 in human RCC has not been fully elucidated. Here, we analyzed TIKI2 mRNA level in RCC specimens, the corresponding non-tumor tissues, RCC cell lines, and human proximal tubule epithelial cell line HK-2 using qPCR. We demonstrated that TIKI2 was highly expressed in RCC tissue (P < 0.05) and most RCC cell lines. In vitro, TIKI2 knockdown significantly inhibited proliferation, invasion, and clone formation ability of 769-P cells compared with controls, while ectopic TIKI2 expression enhanced A498 cell proliferation, invasion, and clone formation ability. In vivo, the average tumor volume was significantly increased in mice injected with A498-Tiki2 cells (P < 0.05). In the 769-P cell TIKI2 knockdown group, the average tumor volume was not significantly different compared to that of the control group (P = 0.08). Moreover, Wnt/β-catenin signaling was not affected by TIKI2 knockdown or overexpression. Results of the present study indicate that TIKI2 is upregulated in RCC tissues and plays an oncogenic role in RCC.

Renal cell carcinoma: links and risks

This review provides an overview of the incidence of renal cell carcinoma (RCC) and a summary of the most commonly associated risk factors. A literature review was performed with a focus on recent studies with a high level of evidence (large prospective cohort studies and meta-analyses). The incidence rate of RCC varies globally, with the rate rising rapidly in more developed regions, demonstrating the effects of increased use of diagnostic imaging and prevalence of modifiable risk factors. Based on the current evidence, cigarette smoking, obesity, and hypertension are the most well-established risk factors for sporadic RCC worldwide. Acquired cystic kidney disease is also a significant risk factor, specifically in dialysis patients. There is increasing evidence for an inverse association between RCC risk and moderate alcohol consumption. Certain analgesics and occupational exposure have been linked to an increased risk of RCC, although data are limited. Diets rich in fruits and vegetables may provide a protective effect.

Robotic partial nephrectomy for renal tumours in obese patients: Perioperative outcomes in a multi-institutional analysis

INTRODUCTION

We sought to evaluate the association of obesity with surgical outcomes of robotic partial nephrectomy (RPN) using a large, multicentre database.

METHODS

We identified 1836 patients who underwent RPN from five academic centres from 2006-2014. A total of 806 patients were obese (body mass index [BMI] ≥30 kg/m(2)). Patient characteristics and outcomes were compared between obese and non-obese patients. Multivariable analysis was used to assess the association of obesity on RPN outcomes.

RESULTS

A total of 806 (44%) patients were obese with median BMI of 33.8kg/m(2). Compared to non-obese patients, obese patients had greater median tumour size (2.9 vs. 2.5cm, p<0.001), mean RENAL nephrometry score (7.3 vs. 7.1, p=0.04), median operating time (176 vs. 165 min, p=0.002), and median estimated blood loss (EBL, 150 vs. 100 ml, p=0.002), but no difference in complications. Obesity was not an independent predictor of operative time or EBL on regression analysis. Among obese patients, males had a greater EBL (150 vs. 100 ml, p<0.001), operative time (180 vs. 166 min, p<0.001) and warm ischemia time (WIT, 20 vs. 18, p=0.001), and male sex was an independent predictor of these outcomes on regression analysis.

CONCLUSIONS

In this large, multicentre study on RPN, obesity was not associated with increased complications and was not an independent predictor of operating time or blood loss. However, in obese patients, male gender was an independent predictor of greater EBL, operative time, and WIT. Our results indicate that obesity alone should not preclude consideration for RPN.

Association of Vitamin E Intake with Reduced Risk of Kidney Cancer: A Meta-Analysis of Observational Studies

Background

Several observational studies suggested that vitamin E intake is related to the risk of kidney cancer; however, the results of published studies are inconsistent.

Material/Methods

A meta-analysis was performed to assess the relationship between vitamin E intake and the risk of kidney cancer by searching PubMed and Medline through August 2015. We computed pooled relative risks (RR) and 95%CI of kidney cancer for the highest versus lowest level of vitamin E intake.

Results

A total of 13 observational studies (7 case-control and 6 cohort) were included. The pooled RR (95%CI) of kidney cancer for the highest vs. the lowest level of vitamin E intake was 0.81 (0.69–0.94). In subgroup-analysis, this study found an inverse relationship between vitamin E intake and kidney cancer risk, which was not significantly modified by study design, study population, or sex distribution except in the cohort studies.

Conclusions

Results of the present study suggest an inverse relationship between vitamin E intake and kidney cancer risk. However, additional well designed cohort studies and randomized controlled trials that focus on the relationship between vitamin E intake and kidney cancer risk are needed.

Association of hypertension and obesity with renal cell carcinoma risk: a report from the Shanghai Men's and Women's Health Studies

PURPOSE

Consistently reported associations between hypertension and obesity and renal cell carcinoma (RCC) risk have largely come from studies in Western populations. These associations were examined in a case-control study nested in the Shanghai Women's Health Study (SWHS, 1996-2000) and Shanghai Men's Health Study (SMHS, 2001-2006).

METHODS

Overall, 271 incident RCC cases (124 women, 147 men) were identified through 31 December 2011, and 2,693 controls were individually matched by sex, age, and calendar time at cohort enrollment, and menopausal status (for women). Participants completed a structured questionnaire by in-person interview at baseline, and conditional logistic regression was used to estimate odds ratios (ORs) and 95 % confidence intervals (CIs).

RESULTS

Self-reported hypertension was associated with a significant 40 % increased risk of RCC among women and men (95 % CI 1.1, 1.9). Body mass index (BMI), modeled continuously, was associated with an elevated risk of RCC among men, with an OR of 1.5 (95 % CI 1.1, 2.0) per 5 kg/m(2) increase in BMI, but not among women.

CONCLUSIONS

Hypertension is independently associated with risk of RCC among both women and men in Shanghai, while overweight and obesity appear to be associated with risk of RCC in Chinese men only.

Obesity is not associated with increased operative complications in single-site robotic partial nephrectomy

PURPOSE

To evaluate the impact of high body mass index (BMI) on outcomes following robotic laparoendoscopic single-site surgery (R-LESS) robotic-assisted laparoscopic partial nephrectomy (RPN).

MATERIALS AND METHODS

Data from 83 Korean patients who had undergone robotic partial nephrectomy from 2006 to 2014 were retrospectively analyzed. The subjects were stratified into two groups according to WHO definitions for the Asian population, consisting of 56 normal range (BMI=18.5-24.99 kg/m²) and 27 obese (≥25 kg/m²) patients. Outcome measurements included Trifecta achievement and the perioperative and postoperative comparison between high and normal BMI series. The measurements were estimated and analyzed with SPSS version 17.

RESULTS

Tumor's complexity characteristics (R.E.N.A.L. score, tumor size) of both groups were similar. No significant differences existed between the two groups with regard to operative time (p=0.27), warm ischemia time (p=0.35) estimated blood loss (p=0.42), transfusion rate (p=0.48) renal function following up for 1 year, positive margins (p=0.24) and postoperative complication rate (p=0.34). Trifecta was achieved in 5 (18.5%) obese and 19 (33.9%) normal weight patients, respectively (p=0.14). In multivariable analysis, only tumor size was significantly correlated with the possibility of Trifecta accomplishment.

CONCLUSION

Our findings suggest that R-LESS RPN can be effectively and safely performed in patients with increased BMI, since Trifecta rate, and perioperative and postoperative outcomes are not significantly different in comparison to normal weight subjects.

Antioxidant micronutrients and the risk of renal cell carcinoma in the Women's Health Initiative cohort

BACKGROUND

Renal cell carcinoma (RCC) is the eighth leading cancer among women in incidence and commonly is diagnosed at a more advanced stage. Oxidative stress has been considered to play an important role in the pathogenesis of RCC. Various dietary micronutrients have antioxidant properties, including carotenoids and vitamins C and E; thus, diets rich in these nutrients have been evaluated in relation to RCC prevention. The objective of this study was to explore the correlation between antioxidant micronutrients and the risk of RCC.

METHODS

In total, 96,196 postmenopausal women who enrolled in the Women's Health Initiative (WHI) between 1993 and 1998 and were followed through July 2013 were included in this analysis. Dietary micronutrient intake was estimated from the baseline WHI food frequency questionnaire, and data on supplement use were collected using an interview-based inventory procedure. RCC cases were ascertained from follow-up surveys and were centrally adjudicated. The risks for RCC associated with intake of α-carotene, β-carotene, β-cryptoxanthin, lutein plus zeaxanthin, lycopene, vitamin C, and vitamin E were analyzed using Cox proportional hazards regression adjusted for confounders.

RESULTS

Two hundred forty women with RCC were identified during follow-up. Lycopene intake was inversely associated with RCC risk (P = .015); compared with the lowest quartile of lycopene intake, the highest quartile of intake was associated with a 39% lower risk of RCC (hazard ratio, 0.61; 95% confidence interval, 0.39-0.97). No other micronutrient was significantly associated with RCC risk.

CONCLUSIONS

The current results suggest that further investigation into the correlation between lycopene intake and the risk of RCC is warranted.

Endoplasmic reticulum protein ERp46 in renal cell carcinoma

An established inverse clinical correlation between serum adiponectin levels and renal cell carcinoma (RCC) aggressiveness exists. We have recently demonstrated that adiponectin suppresses clear cell RCC (ccRCC) progression through interaction with its receptor, adiponectin receptor 1 (AdipoR1). ERp46 has been shown to inhibit adiponectin signaling via interaction with AdipoR1 in HeLa cells. However, the expression of ERp46 in RCC has not been described thus far. The objectives of this study were to investigate ERp46 in RCC, its expression, its effects on RCC growth in a mouse model and whether it interacts with AdipoR1. We demonstrated a higher ERp46/AdipoR1 expression ratio in metastatic compared to non-metastatic ccRCC, as determined by immunohistochemistry of tissue microarrays and subsequent image analysis. When ERp46 was stably knocked down using shRNA or overexpressed in murine RCC RAG cells, RCC growth after subcutaneous injection in BALB/c nude mice was inhibited and accelerated, respectively. In vitro analysis to determine the molecular interaction between AdipoR1 and ERp46 included co-immunoprecipitation using human ccRCC 786-O cells and a bacterial adenylate cyclase-based two hybrid system and demonstrated no sustained AdipoR1-ERp46 interaction. This is the first report to suggest a role for ERp46 as a potential therapeutic target in RCC given its expression profile in human RCC samples and its effect on in vivo RCC growth. Since a stable interaction with AdipoR1 could not be established, we suggest that the tumorigenic properties of ERp46 in RCC cells are not related to an inhibitory modulation of AdipoR1.

An epidemiologic and genomic investigation into the obesity paradox in renal cell carcinoma

BACKGROUND

Obesity increases risk for clear-cell renal cell carcinoma (ccRCC), yet obese patients appear to experience longer survival than nonobese patients. We examined body mass index (BMI) in relation to stage, grade, and cancer-specific mortality (CSM) while considering detection bias, nutritional status, and molecular tumor features.

METHODS

Data were available from 2119 ccRCC patients who underwent renal mass surgery at Memorial Sloan-Kettering Cancer Center between 1995 and 2012. Logistic regression models produced associations between BMI and advanced disease. Multivariable competing risks regression models estimated associations between BMI and CSM. Somatic mutation, copy number, methylation, and expression data were examined by BMI among a subset of 126 patients who participated in the Cancer Genome Atlas Project for ccRCC using the Kruskal-Wallis or Fisher exact tests. All statistical tests were two-sided.

RESULTS

Obese and overweight patients were less likely to present with advanced-stage disease compared with normal-weight patients (odds ratio [OR] = 0.61, 95% confidence interval [CI] = 0.48 to 0.79 vs OR = 0.65, 95% CI = 0.51 to 0.83, respectively). Higher BMI was associated with reduced CSM in univariable analyses (P < .005). It remained statistically significant after adjustment for comorbidities and albumin level, but it became non-statistically significant after adjusting for stage and grade (P > .10). Genome-wide interrogation by BMI suggested differences in gene expression of metabolic and fatty acid genes, including fatty acid synthase (FASN), consistent with the obesity paradox.

CONCLUSIONS

Our findings suggest that although BMI is not an independent prognostic factor for CSM after controlling for stage and grade, tumors developing in an obesogenic environment may be more indolent.

Body mass index and renal cell cancer: the influence of race and sex

BACKGROUND

Obesity is a risk factor for renal cell (or renal) cancer. The increasing prevalence of obesity may be contributing to the rising incidence of this cancer over the past several decades. The effects of early-age obesity and change in body mass index (BMI) on renal cancer have been studied less thoroughly, and the influence of race has never been formally investigated.

METHODS

Using data gathered as part of a large case-control study of renal cancer (1214 cases and 1234 controls), we investigated associations with BMI at several time points, as well as with height. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were computed using logistic regression modeling. Race- and sex-stratified analyses were conducted to evaluate subgroup differences.

RESULTS

Obesity (BMI ≥ 30 kg/m) early in adulthood (OR = 1.6 [95% CI = 1.1 to 2.4]) and 5 years before diagnosis (1.6 [1.1 to 2.2]) was associated with renal cancer. The association with early-adult obesity was stronger among whites than blacks (test for interaction, P = 0.006), whereas the association with obesity near diagnosis was marginally stronger in women than men (test for interaction, P = 0.08). The strongest association with renal cancer was observed for obese whites both in early adulthood and before interview (2.6 [1.5 to 4.4]); this association was not present among blacks. Estimates of the annual excess rate of renal cancer (per 100,000 persons) attributed to both overweight and obesity (BMI > 25 kg/m) ranged from 9.9 among black men to 5.6 among white women.

CONCLUSION

Obesity, both early and later in life, is associated with an increased risk of renal cancer. The association with early obesity seems to be stronger among whites than blacks.

Diet-induced obesity alters dendritic cell function in the presence and absence of tumor growth

Obesity is a mounting health concern in the United States and is associated with an increased risk for developing several cancers, including renal cell carcinoma (RCC). Despite this, little is known regarding the impact of obesity on antitumor immunity. Because dendritic cells (DC) are critical regulators of antitumor immunity, we examined the combined effects of obesity and tumor outgrowth on DC function. Using a diet-induced obesity (DIO) model, DC function was evaluated in mice bearing orthotopic RCC and in tumor-free controls. Tumor-free DIO mice had profoundly altered serum cytokine and chemokine profiles, with upregulation of 15 proteins, including IL-1α, IL-17, and LIF. Tumor-free DIO mice had elevated percentages of conventional splenic DC that were impaired in their ability to stimulate naive T cell expansion, although they were phenotypically similar to normal weight (NW) controls. In DIO mice, intrarenal RCC tumor challenge in the absence of therapy led to increased local infiltration by T cell-suppressive DC and accelerated early tumor outgrowth. Following administration of a DC-dependent immunotherapy, established RCC tumors regressed in normal weight mice. The same immunotherapy was ineffective in DIO mice and was characterized by an accumulation of regulatory DC in tumor-bearing kidneys, decreased local infiltration by IFN-γ-producing CD8 T cells, and progressive tumor outgrowth. Our results suggest that the presence of obesity as a comorbidity can impair the efficacy of DC-dependent antitumor immunotherapies.

Obesity is associated with an improved cancer-specific survival, but an increased rate of postoperative complications after surgery for renal cell carcinoma

OBJECTIVE

This study aimed to assess the impact of preoperative body mass index (BMI) on postoperative complications, cancer-specific survival (CSS) and overall survival (OS) in patients operated for renal cell carcinoma (RCC).

MATERIAL AND METHODS

The study included 397 patients with BMI values, who underwent surgery for RCC between 1 January 1997 and 31 December 2010. Obese patients (BMI > 30 kg/m(2)) were compared to non-obese patients (BMI < 30 kg/m(2)) in regard to CSS and OS. A Cox proportional hazard model was used for the multivariate survival analyses. The mean age of the patients was 62.1 years. There were 259 males (65%) and 325 patients (82%) were non-obese. Mean BMI was 26 kg/m(2).

RESULTS

In the total material, CSS was 94.7% for obese patients and 74.8% for non-obese patients (p = 0.06). The obese group had significantly better CSS in univariate analysis for presumed radically treated disease (pT1-3N0M0). Obesity was a significant protective prognostic factor in multivariate analysis. An accelerating protective effect for CSS was found with increasing levels of BMI. In regard to OS, no difference was found between the two groups. Obese patients had a significantly lower age, and a higher rate of diabetes mellitus, hypertension and incidental detection. Obese patients had a significantly higher total incidence of postoperative complications, but not surgery-related complications.

CONCLUSIONS

In this material, increasing BMI was associated with improved CSS for presumed radically treated patients. However, obese patients had a higher total rate of postoperative complications.

BMI and the risk of renal cell carcinoma

PURPOSE OF REVIEW

Incidence of obesity and renal cell carcinoma (RCC) are increasing, and RCC remains a lethal disease if not identified at an early stage. There is an increasing body of evidence linking obesity to the risk of developing RCC.

RECENT FINDINGS

There is a wealth of epidemiological evidence supporting a higher risk of developing RCC in obese individuals, and in a dose-response manner. This is particularly pertinent in the development of the clear cell subtype (ccRCC), in which there appears to be a special interplay between ccRCC, obesity and von Hippel-Lindau (VHL) gene defects, driving the proangiogenic/proliferative pathway as a result of metabolites produced by adipose tissue, the epigenetic silencing of a tumour suppressor in close proximity to the VHL gene, hypoxia, obesity-related hypertension, lipid peroxidation and increased insulin-like growth factor-1.

SUMMARY

Obesity-related diseases, including cancers, are increasing. There are many complex biomolecular pathways interacting in obesity, especially in ccRCC in which there appears to be a specific interplay in VHL mutations.

Epidemiology and risk factors for kidney cancer

After more than two decades of rising rates, in recent years the total kidney cancer incidence worldwide has shown signs of stabilizing, or even decreasing. In adults, kidney cancer consists of renal cell carcinoma (RCC), the predominant form, and renal transitional cell carcinoma (RTCC); these types primarily arise in the renal parenchyma and renal pelvis, respectively. Although temporal trends by kidney cancer type are not well established worldwide, incidence of RCC in the US has continued to rise, mainly for early-stage tumors, while that of RTCC has declined, and total kidney cancer mortality rates have leveled. Stabilization of kidney cancer mortality rates has also been reported in Europe. These trends are consistent with reports of increasing incidental diagnoses and a downward shift in tumor stage and size in clinical series. The changing prevalence of known risk factors for RCC, including cigarette smoking, obesity, and hypertension, is also likely to affect incidence trends, although their relative impact may differ between populations. Accumulating evidence suggests an etiologic role in RCC for physical activity, alcohol consumption, occupational exposure to trichloroethylene, and high parity among women, but further research is needed into the potential causal effects of these factors. Genetic factors and their interaction with environmental exposures are believed to influence risk of developing RCC, but a limited number of studies using candidate-gene approaches have not produced conclusive results. Large consortium efforts employing genome-wide scanning technology are underway, which hold promise for novel discoveries in renal carcinogenesis.

Minimally invasive treatment of small renal tumors: trends in renal cancer diagnosis and management

Renal cell carcinoma is a common malignancy causing significant mortality. In recent years abdominal imaging, often for alternate symptomatology, has led the trend toward the detection and confirmation of smaller renal tumors. This has permitted the greater use of localized and nephron-sparing techniques including partial nephrectomy and image-guided ablation. This article aims to review the current role of image-guided biopsy and ablation in the management of small renal tumors. The natural history of renal cell carcinoma, the role of renal biopsy, the principles and procedural considerations of thermal energy ablation, and the oncological outcomes of these minimally invasive treatments are discussed and illustrated with cases from the authors' institution. Image-guided ablation, in particular, has changed the treatment paradigm and, by virtue of its increasingly evident efficacy and low morbidity, now favors the treatment of smaller tumors in patients previously unfit for surgery.

Obesity, cholesterol, and clear-cell renal cell carcinoma (RCC)

Multiple epidemiologic studies have linked the development of renal cancer to obesity. In this chapter, we begin with a review of selected population studies, followed by recent mechanistic discoveries that further link lipid deregulation to the RCC development. The upregulation of leptin and downregulation of adiponectin pathways in obesity fit well with our molecular understanding of RCC pathogenesis. In addition, two forms of hereditary RCC involve proteins, Folliculin and TRC8, that are positioned to coordinately regulate lipid and protein biosynthesis. Both of these biosynthetic pathways have important downstream consequences on HIF-1/2alpha levels and angiogenesis, key aspects in the disease pathogenesis. The role of lipid biology and its interface with protein translation regulation represents a new dimension in RCC research with potential therapeutic implications.