Occupational risk factors for renal cell carcinoma: a case-control study

Racial Disparities and Preventive Measures to Renal Cell Carcinoma

Kidney cancer ranks among the top 10 cancers in the United States. Although it affects both male and female populations, it is more common in males. The prevalence rate of renal cell carcinoma (RCC), which represents about 85% of kidney cancers, has been increasing gradually in many developed countries. Family history has been considered as one of the most relevant risk factors for kidney cancer, although most forms of an inherited predisposition for RCC only account for less than four percent. Lifestyle and other factors such as occupational exposure, high blood pressure, poor diet, and heavy cigarette smoking are highly associated with its incidence and mortality rates. In the United States, White populations have the lowest prevalence of RCC compared to other ethnic groups, while Black Americans suffer disproportionally from the adverse effects of RCC. Hence, this review article aims at identifying the major risk factors associated with RCC and highlighting the new therapeutic approaches for its control/prevention. To achieve this specific aim, articles in peer-reviewed journals with a primary focus on risk factors related to kidney cancer and on strategies to reduce RCC were identified. The review was systematically conducted by searching the databases of MEDLINE, PUBMED Central, and Google Scholar libraries for original articles. From the search, we found that the incidence and mortality rates of RCC are strongly associated with four main risk factors, including family history (genetics), lifestyle (poor diet, cigarette smoking, excess alcohol drinking), environment (community where people live), and occupation (place where people work). In addition, unequal access to improvement in RCC cancer treatment, limited access to screening and diagnosis, and limited access to kidney transplant significantly contribute to the difference observed in survival rate between African Americans and Caucasians. There is also scientific evidence suggesting that some physicians contribute to racial disparities when performing kidney transplant among minority populations. New therapeutic measures should be taken to prevent or reduce RCC, especially among African Americans, the most vulnerable population group.

Occupation and renal cell cancer in Central and Eastern Europe

OBJECTIVE

Central and Eastern Europe has among the highest rates of renal cell cancer worldwide. Few studies have been conducted in these areas to investigate the possible role of occupational exposures in renal cell cancer aetiology. The purpose of this study was to examine the association of renal cell cancer with employment in specific occupations and industries.

METHODS

From 1999 to 2003, we conducted a hospital-based case-control study in seven areas of the Czech Republic, Poland, Romania and Russia. A detailed occupational history was collected from renal cell cancer cases and controls, together with information on potential confounders. Odds ratios (ORs) and 95% CI of cancer risk were calculated for having ever been employed in selected jobs and industries, with follow-up analyses examining duration of employment.

RESULTS

A total of 992 histologically confirmed incident renal cell cancer cases and 1459 controls were included in the analysis. An increased risk of renal cell cancer was observed for workers in agricultural labour and animal husbandry (OR 1.43; 95% CI 1.05 to 1.93), particularly among women employed as general farm workers (OR 2.73; 95% CI 1.05 to 7.13). Risk gradients for agricultural work increased with longer employment. An overall increased risk of renal cell cancer was seen among architects and engineers (OR 1.89; 95% CI 1.35 to 2.65), and mechanical engineers (OR 1.71; 95% CI 1.03 to 2.84).

CONCLUSIONS

Our data suggest an association between renal cell cancer and agricultural work, particularly among female workers.

Lifestyle Factors, Exposures, Genetic Susceptibility, and Renal Cell Cancer Risk: A Review

Malignant kidney tumors account for approximately 2% of all new primary cancer cases diagnosed in the United States, with an estimated 30,000 cases occurring annually. Although a variety of agents, chemical and biological, have been implicated as causal agents in the development of renal cell carcinoma (RCC), the etiology remains enigmatic. The strongest association has been developed between cigarette smoking and renal cancer however consistent, positive associations between RCC and obesity, diabetes, and hypertension have also been reported. In addition, more recent investigations of familial kidney cancer syndromes indicate that a strong genetic component contributes to RCC development. Several genes have been identified through investigation of familial kidney cancer syndromes. This review article describes recent trends in RCC incidence and the currently identifiable etiological causes that account for approximately half of the RCC cases diagnoses. The remainder of this review then focuses on additional risk factors that have thus far not been well examined but may be helpful in explaining the increasing incidence trends and the geographic or racial variation observed nationally and worldwide.

Renal cancer

In Europe, renal cancer (that is neoplasia of the kidney, renal pelvis or ureter (ICD-9 189 and ICD-10 C64-C66)) ranks as the seventh most common malignancy in men amongst whom there are 29,600 new cases each year (3.5% of all cancers). Tobacco, obesity and a diet poor in vegetables are all acknowledged risk factors, along with specific occupational and environmental factors. A familial history of renal carcinoma is also likely to increase the risk. Renal carcinoma may remain clinically occult for most of its course. The classic presentation of pain, haematuria, and flank mass occurs in only 9% of patients and is often indicative of advanced disease. Approximately 30% of patients with renal carcinoma present with metastatic disease, 25% with locally advanced renal carcinoma and 45% with localized disease. Metastases are typically found in the lung, soft tissue, bone, liver, cutaneous sites, and central nervous system. The most important staging technique is a computed tomography (CT) scan of the whole abdomen. Survival rates are more favourable for patients with tumours confined to the kidney. Five-year survival for patients with metastatic renal carcinoma is comprised between 0 and 20%. Radical nephrectomy is the standard intervention for renal cancer. Intrinsic resistance to chemotherapy has long been a hallmark of renal carcinoma. Limited options are available for the systemic therapy, and no chemotherapeutic regimen is accepted as a standard of care. Biologic agents represent the major effective therapies for widespread metastatic renal cancer. An antiangiogenic strategy, the neutralization of VEGF, can slow the growth rate of advanced cancer.

Occupational risk factors for kidney cancer: a cohort study in Sweden

Although many studies have examined the associations between occupational exposures and kidney cancer, the evidence is not consistent. To examine the risk of occupational exposures on kidney cancer, we carried out a follow-up study on the economically active Swedish population, based on the latest update of the Swedish Family-Cancer Database. We calculated standardized incidence ratios (SIR) and 95% confidence intervals (CIs) for different occupational groups, adjusted for age, period, and socioeconomic status. The reference group was all the economically active population. An increased risk of renal parenchymal cancer was observed for miners and quarry workers, drivers, sales agents, transport workers, and public safety and protection workers among men, and launderers and dry cleaners among women. Significantly increased SIRs of renal pelvical cancer were also observed for the food manufacture workers among men, and journalists and shoe and leather industry workers among women. Male forestry workers, smelters, and metal foundry workers had increased risk for unspecified kidney cancer. Although smoking may explain some of these results, exposure to gasoline, diesel, their exposure products, some metal and chemicals in shoe and leather works, and dry-cleaning products may be associated with kidney cancer.

Risk factors for adult renal cell carcinoma

This study confirmed several independent risk and protective factors for RCC identified in the authors' previous study. Protective factors such as oral contraceptive use and moderate alcohol consumption were identified only in women. Tobacco consumption and severe obesity were the main independent risk factors. There were other modifiable risk markers, however, such as occupational exposure, thiazidic drug intake, and urinary tract infections. The associations between risk factors and RCC were weak, even for tobacco, for which the association was weaker than that for lung cancer. The identified risks involve a large proportion of the population, however, and the risk attributable to these types of exposure is high. The authors' recommendations for the prevention of RCC are therefore similar to those for the prevention of cardiovascular disease and cancer, and should be disseminated to the general population. The high-risk groups identified are too large for a specific early-screening program for RCC, but such screening might be appropriate if restricted to selected age groups.

Critical review of the epidemiological literature on occupational exposure to perchloroethylene and cancer

OBJECTIVES

Of an estimated 500,000 workers in the USA potentially exposed to perchloroethylene (PCE), the largest share is employed in the dry-cleaning industry. PCE, a non-flammable solvent, has commercial applications as a chemical intermediate, metal degreaser and, since the 1950s, primary solvent in the dry-cleaning industry. The International Agency for Research on Cancer (IARC) currently finds sufficient evidence to designate PCE as carcinogenic in animals, with limited evidence in humans. With regard to occupational exposure through dry-cleaning, PCE is considered to be possibly carcinogenic to humans. This review was conducted to assess the current epidemiological literature on PCE and specific cancers.

METHODS

A comprehensive search was conducted to identify all available epidemiological literature pertaining to the carcinogenic effects of PCE. Forty-four papers that provided reasonable data on up to 17 cancer sites were critically reviewed in the context of the available background literature for each cancer site and were assessed on the basis of specified methodological and scientific quality criteria.

RESULTS

While all the epidemiological studies selected for review investigated similar exposure-health outcome relationships, there was a broad diversity of proxy measurements of exposure to PCE, as well as numerous specific cancer outcomes of interest. The widespread lack of valid exposure measurements or other adequate indicators of potential for exposure were consistent limitations. We found no evidence of an association between breast, prostate, skin or brain cancer and exposure to PCE. A relationship between PCE and cancer of the following sites was considered unlikely: oral cavity, liver, pancreas, cervix lung. Scientific evidence was inadequate for laryngeal, kidney, esophageal and bladder cancers.

CONCLUSIONS

The current epidemiological evidence does not support a conclusion that occupational exposure to PCE is a risk factor for cancer of any specific site. Priority areas in which additional data are most needed include cancers of the esophagus and bladder.

Occupational risk factors for renal cell cancer: a case--control study in northern Italy

Relatively little is known about occupational and other risk factors for renal-cell carcinoma (RCC). Associations between RCC and occupations, exposures and other factors were investigated in a hospital-based case-control study in Bologna (central-northern Italy). Between 1986 and 1994, 324 histologically confirmed RCC cases were diagnosed at Policlinico S. Orsola-Malpighi in patients from the Province of Bologna. Corresponding control subjects admitted to the same hospital with any diagnosis except RCC were matched for sex, age, and residency. We studied the 249 cases and 238 controls for whom detailed information on occupational history, diet, smoking habits, alcohol and drug intake was obtained. At conditional logistic regression, among males (167 matched pairs), significant matched odds ratios (OR) were found, after adjusting for cigarette smoking and alcohol intake, for high body-mass index BMI (third quartile: OR, 4.91; confidence interval [95% CI], 1.56-15.5; last quartile: OR, 4.42; 95% CI, 1.48-13.18), railway workers (OR, 10.14; 95% CI, 1.46-70.17) and asbestos exposure (OR, 7.11; 95% CI, 1.46-34.51); nearly significant OR were found for managers (OR, 3.59; 95% CI, 0.82-15.59) and metal workers (OR, 2.21; 95% CI, 0.99-5.37). Among females (52 pairs), significant OR were found for BMI > 25.4 (OR, 8.46; 95% CI, 1.02-68.0). Railway workers (on or near to trains) may have increased risk of developing RCC, possibly due to asbestos exposure. Studies are required on possible risks encountered by railway (and metal) workers and by managers.

Occupational risk factors for renal cell carcinoma: agent-specific results from a case-control study in Germany. MURC Study Group. Multicenter urothelial and renal cancer study

BACKGROUND

This case-control study was conducted to estimate the renal cell cancer (RCC) risk for exposure to occupation-related agents, besides other suspected risk factors.

METHODS

In a population-based multicentre study, 935 incident RCC cases and 4298 controls matched for region, sex, and age were interviewed between 1991 and 1995 for their occupational history and lifestyle habits. Agent-specific exposure was expert-rated with two job-exposure matrices and a job task-exposure matrix. Conditional logistic regression was used to calculate smoking adjusted odds ratios (OR).

RESULTS

Very long exposures in the chemical, rubber, and printing industries were associated with risk for RCC. Males considered as 'substantially exposed to organic solvents' showed a significant excess risk (OR = 1.6, 95% CI : 1.1-2.3). In females substantial exposure to solvents was also a significant risk factor (OR = 2.1, 95% CI : 1.0-4.4). Excess risks were shown for high exposure to cadmium (OR = 1.4, 95% CI : 1.1-1.8, in men, OR = 2.5, 95% CI : 1.2-5.3 in women), for substantial exposure to lead (OR = 1.5, 95% CI : 1.0-2.3, in men, OR = 2.6, 95% CI : 1.2-5.5, in women) and to solder fumes (OR = 1.5, 95% CI : 1.0-2.4, in men). In females, an excess risk for the task 'soldering, welding, milling' was found (OR = 3.0, 95% CI : 1.1-7.8). Exposure to paints, mineral oils, cutting fluids, benzene, polycyclic aromatic hydrocarbons, and asbestos showed an association with RCC development.

CONCLUSIONS

Our results indicate that substantial exposure to metals and solvents may be nephrocarcinogenic. There is evidence for a gender-specific susceptibility of the kidneys.

Occupational risk factors for renal cell carcinoma in Montreal

BACKGROUND

Little is known about the role of workplace exposures on the risk of renal cell cancer.

METHODS

A population-based case-control study was undertaken in Montreal to assess the association between hundreds of occupational circumstances and several cancer sites, including the kidney. A total of 142 male patients with pathologically confirmed renal cell carcinoma, 1900 controls with cancer at other sites and 533 population-based controls were interviewed. Detailed job histories and relevant data on potential confounders were obtained. A group of chemists-hygienists evaluated each job reported and translated them into a history of occupational exposures using a checklist of 294 substances. Multivariate logistic regression models using either population, cancer controls, or a pool of both groups were used to estimate odds ratios.

RESULTS

There were some indications of excess risks among printers, nursery workers (gardening), aircraft mechanics, farmers, and horticulturists, as well as in the following industries: printing-related services, defense services, wholesale trade, and retail trade. Notwithstanding the low precision of many of the odds ratio estimates, the following workplace exposures showed some evidence of excess risk: chromium compounds, chromium (VI) compounds, inorganic acid solutions, styrene-butadiene rubber, ozone, hydrogen sulphide, ultraviolet radiation, hair dust, felt dust, jet fuel engine emissions, jet fuel, aviation gasoline, phosphoric acid and inks.

CONCLUSIONS

For most of these associations there exist no, or very little, previous data. Some associations provide suggestive evidence for further studies.

Trichloroethylene and cancer: epidemiologic evidence

Trichloroethylene is an organic chemical that has been used in dry cleaning, for metal degreasing, and as a solvent for oils and resins. It has been shown to cause liver and kidney cancer in experimental animals. This article reviews over 80 published papers and letters on the cancer epidemiology of people exposed to trichloroethylene. Evidence of excess cancer incidence among occupational cohorts with the most rigorous exposure assessment is found for kidney cancer (relative risk [RR] = 1.7, 95% confidence interval [CI] 1.1-2.7), liver cancer (RR = 1.9, 95% CI(1.0-3.4), and non-Hodgkin's lymphoma (RR = 1.5, 95% CI 0.9-2.3) as well as for cervical cancer, Hodgkin's disease, and multiple myeloma. However, since few studies isolate trichloroethylene exposure, results are likely confounded by exposure to other solvents and other risk factors. Although we believe that solvent exposure causes cancer in humans and that trichloroethylene likely is one of the active agents, we recommend further study to better specify the specific agents that confer this risk and to estimate the magnitude of that risk.

Gender differences in risk of renal cell carcinoma and occupational exposures to chlorinated aliphatic hydrocarbons

BACKGROUND

Organic solvents have been associated with renal cell cancer; however, the risk by gender and type of solvents is nuclear.

METHODS

We evaluated the risk of renal cell carcinoma among men and women exposed to all organic solvents-combined, all chlorinated aliphatic hydrocarbons (CAHC)-combined, and nine individual CAHC using a priori job exposure matrices developed by NCI in a population-based case-control study in Minnesota, U.S. We interviewed 438 renal cell cancer cases (273 men and 165 women) and 687 controls (462 men and 225 women).

RESULTS

Overall, 34% of male cases and 21% of female cases were exposed to organic solvents in general. The risk of renal cell carcinoma was significantly elevated among women exposed to all organic solvents combined (OR = 2.3; 95% CI = 1.3-4.2), to CAHC combined (OR = 2.1; 95% CI = 1.1-3.9), and to trichloroethylene (TCE) (OR = 2.0; 95% CI = 1.0-4.0). Among men, no significant excess risk was observed among men exposed to any of these nine individual CAHCs, all CAHCs-combined, or all organic solvents-combined.

DISCUSSION

These observed gender differences in risk of renal cell carcinoma in relation to exposure to organic solvents may be explained by chance based on small numbers, or by the differences in body fat content, metabolic activity, the rate of elimination of xenobiotics from the body, or by differences in the level of exposure between men and women, even though they have the same job title.