Diabetes and kidney cancer outcomes: a propensity score analysis

Effect of smoking, hypertension and lifestyle factors on kidney cancer - perspectives for prevention and screening programmes

Renal cell carcinoma (RCC) incidence has doubled over the past few decades. However, death rates have remained stable as the number of incidental renal mass diagnoses peaked. RCC has been recognized as a European health care issue, but to date, no screening programmes have been introduced. Well-known modifiable risk factors for RCC are smoking, obesity and hypertension. A direct association between cigarette consumption and increased RCC incidence and RCC-related death has been reported, but the underlying mechanistic pathways for this association are still unclear. Obesity is associated with an increased risk of RCC, but interestingly, improved survival outcomes have been reported in obese patients, a phenomenon known as the obesity paradox. Data on the association between other modifiable risk factors such as diet, dyslipidaemia and physical activity with RCC incidence are conflicting, and potential mechanisms underlying these associations remain to be elucidated.

Cause-specific mortality among patients with renal cell carcinoma in the United States from 2000 to 2018

OBJECTIVES

There has been little focus on the non-cancer causes of death in patients with renal cell carcinoma (RCC). Therefore, we aimed to assess the frequency and risk of different causes of death, stratified by tumor stage, and demographics, after a diagnosis of RCC in the United States.

MATERIALS AND METHODS

Data on eligible patients with RCC from January 1, 2000, to December 31, 2018, in the United States were retrieved from the Surveillance, Epidemiology, and End Results (SEER) database. Standardized mortality ratios for causes of death were calculated using the SEER*Stat software 8.3.9.2 for the overall population and stratified subgroups.

RESULTS

A total of 165,969 patients with RCC were included and 60,290 (36.3%) died during follow-up. The majority of deaths were due to kidney cancer (51.3%) but a significant proportion was non-cancer causes (37.6%). The proportion of deaths attributed to RCC decreased with increasing follow-up with non-cancer causes becoming dominant after the fifth year following RCC diagnosis. Overall, cardiovascular diseases and cerebrovascular diseases were the most common non-RCC-related causes of death. AJCC stage I and localized RCC had the most deaths attributed to non-cancerous causes (66.2% and 61.2%, respectively) while AJCC stage IV and distant RCC had the most deaths due to RCC (86.2% and 86.5%, respectively).

CONCLUSION

A large proportion of RCC patients die of non-cancerous causes especially early-stage patients and advanced-stage patients who survive >5 years. Coordination of multidisciplinary care with relevant specialists depending on the stage of the disease is needed to better prevent death overtime from non-cancer causes.

Diabetes and kidney cancer survival in patients undergoing nephrectomy: A Canadian multi-center, propensity score analysis

INTRODUCTION

Diabetes has been associated with worse survival outcomes in various malignancies; however, there are conflicting data in kidney cancer. Determining whether diabetes is associated with survival in kidney cancer may help guide treatment in a comorbid patient population.

METHODS

We used the Canadian Kidney Cancer information system database to identify patients undergoing partial or radical nephrectomy between 1989 and 2017 for localized renal cell carcinoma at 16 institutions across Canada. We derived inverse probability of treatment weights (IPTW) from a propensity score model based on various clinical, surgical, and pathological characteristics. We used Cox proportional hazard models to evaluate the association between diabetes and cancer-specific and overall survival, in the sample weighted by the IPTW.

RESULTS

4828 patients met inclusion criteria, of whom 948 (19.6%) were diabetic. Median follow-up in those without death was 26.6 months (interquartile range 9.7-53.8). Among the entire cohort, 901 deaths were from any cause, and 299 deaths from kidney cancer. Before propensity score methods, diabetics were older, more likely to have comorbidities and clear cell histopathology. After propensity score adjustment, all characteristics were balanced between groups (standardized difference <0.10). IPTW-adjusted Cox proportional hazard models demonstrated no significant association between diabetes and cancer-specific (hazard ratio 1.13, 95% confidence interval 0.78-1.62), or overall survival (hazard ratio 1.14, 95% confidence interval 0.94-1.38).

CONCLUSIONS

Our multi-centre study found that diabetes and nondiabetics have similar survival following nephrectomy for kidney cancer.

Type 2 Diabetes in Relation to the Risk of Renal Cell Carcinoma Among Men and Women in Two Large Prospective Cohort Studies

OBJECTIVE

We assessed whether type 2 diabetes is associated with renal cell carcinoma (RCC), independent of key potential confounders, in two large prospective cohorts with biennially updated covariate data.

RESEARCH DESIGN AND METHODS

A total of 117,570 women from the Nurses' Health Study (NHS) and 48,866 men from the Health Professionals Follow-Up Study (HPFS) were followed from 1976 and 1986, respectively, through 2014. Multivariable Cox proportional hazards models were used to calculate hazard ratios (HRs) and 95% CIs for associations between type 2 diabetes and pathology-confirmed RCC, overall and by stage, grade, and histologic subtype.

RESULTS

During 38 years of follow-up in the NHS, we confirmed 418 RCC case subjects, including 120 fatal cases. Over 28 years in the HPFS, we confirmed 302 RCC case subjects, including 87 fatal cases. Women with type 2 diabetes had a significantly increased risk of RCC compared with women without type 2 diabetes (multivariable HR 1.53; 95% CI 1.14-2.04), with some evidence that the association was stronger for ≤5 (HR 2.15; 95% CI 1.44-3.23) than >5 (HR 1.22; 95% CI 0.84-1.78) years' duration of type 2 diabetes (P_difference 0.03). Among men, type 2 diabetes was not associated with total RCC (HR 0.89; 95% CI 0.56-1.41) or with RCC defined by stage, grade, or subtype. Sample sizes for analyses by stage, grade, and subtype were limited.

CONCLUSIONS

We found that type 2 diabetes was independently associated with a greater risk of RCC in women but not in men.

The value of complementing administrative data with abstracted information on smoking and obesity: A study in kidney cancer

INTRODUCTION

Variables, such as smoking and obesity, are rarely available in administrative databases. We explored the added value of including these data in an administrative database study evaluating the association of statin use with survival in kidney cancer.

METHODS

We linked administrative data with chart-abstracted data on smoking and obesity for 808 patients undergoing nephrectomy for kidney cancer. Base models consisted of variables from administrative databases (age, sex, year of surgery, and different measures of comorbidity [to compare their sensitivity to smoking and obesity data]); extended models added chart-abstracted data. We compared coefficients for statin use with overall (OS) and cancer-specific survival (CSS), and used the c-statistic and net reclassification improvement (NRI) to compare predications of five-year survival obtained from Cox proportional hazard models.

RESULTS

The coefficient for statin use changed minimally following addition of abstracted data (<6% for OS, <2% for CSS). Base models performed similarly for OS, with c-statistics of 0.75 (95% confidence interval [CI] 0.72-0.79) for Charlson score and 0.73 (95% CI 0.69-0.78) for John Hopkins Aggregated Diagnosis Groups score. After including abstracted data, c-statistics modestly improved (change <0.02); CSS demonstrated similar findings. NRIs were 0.210 (95% CI 0.062-0.297) and 0.186 (-0.031-0.387) when using the Charlson score, and 0.207 (0.068-0.287) and 0.197 (0.007-0.399) when using the Aggregated Diagnosis Groups score, for OS and CSS, respectively.

CONCLUSIONS

The inclusion of data on smoking and obesity marginally influences survival models in kidney cancer studies using administrative data.

Metabolic Syndrome Negatively Impacts the Outcome of Localized Renal Cell Carcinoma

The aim of this study was to analyze the impact of metabolic syndrome (MetS) on outcome of patients with localized renal cell carcinoma (RCC). A retrospective database was compiled consisting of 646 patients who underwent surgery for localized RCC between 2005 and 2014. A total of 439 patients were eligible for final analysis. For diagnosis of MetS, the WHO criteria of 1998 were used. Median follow-up was 32 months (ranging from 2 to 119). Kaplan-Meier and log-rank analyses were performed to compare patients with and without MetS or its components. Univariate and multivariate logistic regression identified prognostic factors for progression-free survival (PFS), cancer-specific survival (CSS), and overall survival (OS). In our cohort, 9.8% (n = 43) of patients were diagnosed with MetS. There were no differences between patients with and without MetS regarding clinicopathological parameters with the exception of patients' age (p = 0.002). Kaplan-Meier and log-rank analyses revealed a shorter PFS for patients with MetS (p = 0.018), whereas no differences were found for each of the single components of MetS, namely, diabetes mellitus (DM) (p = 0.332), BMI >30 kg/m² (p = 0.753), hypertension (p = 0.451), and hypertriglyceridemia (p = 0.891). Logistic regression identified age (HR = 1.92, p = 0.03), tumor stage (HR = 4.37, p < 0.001), grading (HR = 4.57, p < 0.001), nodal status (HR = 3.73, p = 0.04), surgical margin (HR = 1.96, p = 0.04), concomitant sarcomatoid differentiation (HR = 5.06, p < 0.001), and MetS (HR = 1.98, p = 0.04) as independent factors for PFS. For CSS, only age (HR = 2.62, p = 0.035), tumor stage (HR = 3.06, p < 0.02), and grading (HR = 6.83, p < 0.001) were significant. In conclusion, patients with localized RCC and MetS show significantly reduced PFS and might profit from specific consultation and follow-up.