Kidney cancer represents an increasing global public health challenge, with its incidence rising due to aging populations, lifestyle transitions, and advances in diagnostic technologies. However, this growth is unevenly distributed across regions, driven by disparities in healthcare access, socioeconomic conditions, and lifestyle factors such as smoking and hypertension.
In China specifically, kidney cancer incidence and mortality have escalated significantly, fueled by an aging population, urbanization, and higher prevalence of risk factors. Rural areas face disproportionately late-stage diagnoses due to healthcare inequities, while urban centers benefit from improved diagnostic capabilities including CT and MRI imaging.
Globally, notable gender differences persist, as men consistently exhibit higher rates of both incidence and mortality compared to women. Men aged 60 and older are especially likely to develop kidney cancer, though the reasons for this gender gap are not fully understood. Genetic, environmental, and hormonal factors may all contribute to this disparity.
The Global Burden of Disease (GBD) database provides standardized data on kidney cancer trends across countries and time periods. This study leveraged GBD 2021 data to analyze kidney cancer trends and risk factor contributions in China and globally from 1990 to 2021, aiming to inform targeted public health strategies.
This study utilized data from the Global Burden of Disease (GBD) 2021 database to explore trends in kidney cancer between 1990 and 2021. Critical indicators examined included age-standardized rates (ASRs) for incidence, prevalence, mortality, and disability-adjusted life years (DALYs), allowing for fair comparisons across populations with different age structures.
Data were stratified by age, gender, and geographic region to explore potential disparities in kidney cancer burden. Age groups were categorized into 5-year intervals from 0 to 95+ years. The study also investigated modifiable risk factors including smoking, occupational exposure to trichloroethylene, and high body mass index (BMI).
Joinpoint regression analysis was applied to examine temporal changes in kidney cancer burden, fitting multiple line segments to the data to identify periods with distinct trends. Annual percentage change (APC) was computed for each period, with statistical significance tested at a 0.05 threshold.
Advanced modeling approaches were employed, including Disease Modeling-Meta-Regression (DisMod-MR) and the Cause of Death Ensemble model (CODEm), to synthesize and standardize data across multiple sources, accounting for discrepancies in reporting and providing robust estimates even for countries with incomplete data.
From 1990 to 2021, kidney cancer in China exhibited substantial increases across all metrics. The age-standardized incidence rate (ASIR) grew from 1.794 to 3.319 per 100,000, representing an average annual percentage change (AAPC) of 1.98%. The prevalence rate rose even more dramatically from 7.191 to 17.754 per 100,000, with an AAPC of 2.95%.
Mortality rates experienced a more moderate rise, with the age-standardized mortality rate (ASMR) increasing from 1.14 to 1.246 per 100,000. The AAPC for mortality was 0.22%, suggesting a relatively slower rate of increase in mortality compared to incidence and prevalence, likely reflecting improvements in treatment and early detection.
Although DALYs rose significantly in absolute numbers (from 346,829 to 663,805), the age-standardized DALY rate actually declined marginally from 35.838 to 34.176 per 100,000, indicating a modest decrease in DALY burden relative to population growth and changes in age structure over three decades.
In China, contributions of smoking and high BMI to kidney cancer mortality and DALYs increased substantially over the study period, while occupational exposure to trichloroethylene remained stable. These findings highlight the growing influence of modifiable lifestyle risk factors on China's kidney cancer burden.
Globally, kidney cancer incidence increased from 159,774 cases in 1990 to 387,829 in 2021, with the ASIR rising from 3.886 to 4.524 per 100,000. The total number of prevalent cases more than doubled, from 751,618 to 1,961,211, reflecting both rising new diagnoses and improved survival rates leading to more people living with the disease.
In contrast to rising incidence, the global ASMR showed a slight decrease from 1.994 to 1.912 per 100,000, yielding a negative AAPC of -0.13%. This divergence between increasing incidence and stable or declining mortality suggests progress in early detection, treatment modalities, and disease management, particularly in high-income countries.
The global age-standardized DALY rate declined from 53.017 to 47.327 per 100,000, with an AAPC of -0.37%. This steady reduction indicates overall improvements in managing kidney cancer globally, though the benefits have not been uniformly distributed, as low- and middle-income countries (LMICs) continue to face barriers to advanced diagnostic and therapeutic options.
Globally, high BMI surpassed smoking as the leading modifiable risk factor for kidney cancer mortality and DALYs. The proportion of deaths attributable to high BMI rose steadily, while smoking's contribution remained relatively stable. Occupational trichloroethylene exposure played a minimal role at the global level.
Joinpoint regression revealed noteworthy fluctuations in kidney cancer trends in both China and worldwide. In China, the ASIR exhibited marked increases during 1997-2004, 2004-2011, and 2016-2021, while the ASPR followed a similar pattern of elevation between 1998-2002 and 2002-2009, interspersed with intervals of non-significant changes.
China's ASMR declined from 1990 to 1997 (APC = -1.21) but then underwent significant increases from 1997 to 2002 and continued a gradual upward trend from 2014 to 2021. The ASDR decreased during the early 1990s and again from 2003 to 2021, except for a brief increase between 1997 and 2003.
Globally, the ASIR increased from 1990 to 1995 (APC = 1.89) but showed a notable decrease from 2015 to 2021 (APC = -0.84). The global ASMR showed early increases from 1990 to 1994 but subsequently declined significantly from 2003 to 2021, paralleled by a downward trend in ASDR beginning in 1994.
These temporal patterns underscore both regional and global shifts in kidney cancer epidemiology, with China showing persistent upward trends in incidence and prevalence while global mortality and DALY rates have begun stabilizing or declining, reflecting differential progress in cancer control strategies across regions.
The kidney cancer burden disproportionately affects older populations. By 2021, incidence numbers had surged across all age brackets in China, particularly among individuals aged 55 to 84 years, with the highest rates in the 75-79 age group. Prevalence peaked in the 65-74 age range, while mortality was highest among those aged 75-79.
Significant gender disparities were observed in both China and globally. Males consistently exhibited higher incidence, prevalence, mortality, and DALY rates compared to females across all time periods and age groups. In China, the incidence disparity between genders widened with increasing age, peaking in the 70-74 age group.
While biological factors such as hormonal differences and genetic predispositions may partly explain the gender gap, behavioral and environmental risk factors likely play significant roles. Men tend to have higher smoking rates and greater occupational exposure to nephrotoxic agents like trichloroethylene, contributing to their elevated burden.
The peak DALY burden shifted from younger populations and older adults in 1990 to individuals aged 55-79 contributing the most by 2021, highlighting the growing impact of kidney cancer on working-age and early-retirement populations in terms of both health and productivity losses.
The rising kidney cancer burden in China is linked to multiple factors including population aging, urbanization, and increased prevalence of lifestyle-related risks such as smoking, hypertension, and obesity. Improved diagnostic capabilities in urban areas have contributed to increased detection rates, but this improvement has not been evenly distributed across regions.
Rural areas in China continue to experience healthcare disparities that delay diagnosis and result in poorer outcomes. These results underscore the pressing need for equitable healthcare initiatives to address disparities and enhance access to early detection and treatment in underserved regions.
Globally, while high-income countries have seen declining mortality through advances in imaging technologies and targeted therapies including immune checkpoint inhibitors, LMICs continue to face barriers to accessing advanced diagnostic and therapeutic options, leading to higher mortality rates in these regions.
The study also highlights that the GBD database, while comprehensive, synthesizes estimates from diverse sources that may introduce variability. It does not account for certain risk factors such as dietary habits, physical activity levels, and environmental exposures, which may also influence kidney cancer trends.
Addressing the rising kidney cancer burden requires targeted public health interventions. In China, reducing urban-rural gaps in healthcare access and improving early diagnosis capabilities in underserved areas are critical priorities. Metabolic interventions targeting high BMI and smoking cessation programs are essential given the increasing contribution of these modifiable risk factors.
Gender-specific prevention strategies are needed, including targeted smoking cessation programs for men and workplace safety regulations to reduce occupational trichloroethylene exposure. Integrating cancer screening and management into geriatric care frameworks is also important given the aging demographics of kidney cancer patients.
Future research should focus on identifying additional modifiable risk factors, exploring genetic and environmental determinants, and evaluating the cost-effectiveness of various prevention and treatment strategies. Longitudinal studies are needed to assess the long-term impact of emerging therapies and public health interventions.
The findings carry important implications for public health policy and resource distribution globally. Early intervention strategies appear effective at reducing DALY rates among younger age groups, but sustaining these gains will require ongoing investment in public health initiatives and healthcare infrastructure worldwide.
This comprehensive analysis of kidney cancer trends from 1990 to 2021 reveals a rising burden in both China and globally, with notable disparities by region, gender, and age group. In China, incidence and prevalence have increased substantially, while globally, mortality and DALY rates have begun to stabilize or decline in response to improved detection and treatment.
The results highlight the critical need for targeted prevention, early diagnosis, and equitable access to advanced treatments, especially in LMICs and underserved populations. High BMI has emerged as the leading global risk factor, surpassing smoking, which signals a shift in the modifiable risk landscape for kidney cancer.
Tackling kidney cancer effectively will require a multi-pronged approach: public health campaigns targeting obesity and smoking, equitable distribution of diagnostic technologies, gender-specific intervention strategies, and sustained investment in healthcare infrastructure. Reducing disparities in cancer care remains the most pressing challenge.