Pesticides, soft-tissue sarcoma and non-Hodgkin lymphoma--historical aspects on the precautionary principle in cancer prevention

Exposure to phenoxyacetic acids and glyphosate as risk factors for non-Hodgkin lymphoma- pooled analysis of three Swedish case-control studies including the sub-type hairy cell leukemia

The association between pesticide exposure and non-Hodgkin lymphoma (NHL) including hairy cell leukemia (HCL) was analyzed in a pooled study of three case-control studies. Results on exposure to pesticides were based on 1,425 cases and 2,157 controls participating in the studies. Exposures were assessed by self-administered questionnaires completed as needed by phone. In the pooled univariate analyses adjusted by age, gender and year of diagnosis, exposure to herbicides of the phenoxyacetic acid type yielded statistically significant increased risk with odds ratio (OR) = 1.9, 95% confidence interval CI) = 1.4-2.5. The herbicide glyphosate gave OR = 2.2, 95% CI = 1.3-3.8. Impregnating agents increased the risk. No clear dose-response effect was seen. OR was highest in the >10-20 years latency group for herbicides and impregnating agents. In the multivariate analysis including main pesticide groups, statistically significant increased risk was found for herbicides, OR = 1.6, 95% CI = 1.2-2.1 and impregnating agents with OR = 1.4, 95% CI = 1.1-1.8. This analysis confirmed an association between NHL including HCL and exposure to certain herbicides.

Odor emissions: A public health concern for health risk perception

The olfactory nuisance, due to the emissions of active molecules, is mainly associated with unproperly managed waste disposal and animal farming. Volatile compounds e.g., aromatics, organic and inorganic sulfide compounds, as well as nitrogen and halogenated compounds are the major contributor to odor pollution generated by waste management plants; the most important source of atmospheric ammonia is produced by livestock farming. Although an odorous compound may represent a nuisance rather than a health risk, long-term exposure to a mixture of volatile compounds may represent a risk for different diseases, including asthma, atopic dermatitis, and neurologic damage. Workers and communities living close to odor-producing facilities result directly exposed to irritant air pollutants through inhalation and for this reason the cumulative health risk assessment is recommended. Health effects are related to the concentration and exposure duration to the odorants, as well as to their irritant potency and/or biotransformation in hazardous metabolites. The health effects of a single chemical are well known, while the interactions between molecules with different functional groups have still to be extensively studied. Odor emissions are often due to airborne pollutants at levels below the established toxicity thresholds. The relationship between odor and toxicity does not always occurs but depends on the specific kind of pollutant involved. Indeed, some toxic agents does not induce odor nuisance while untoxic agents do. Accordingly, the relationship between toxicity and odor nuisance should be always analyzed in detail evaluating on the characteristics of the airborne mixture and the type of the source involved.

Lost opportunities for cancer prevention: historical evidence on early warnings with emphasis on radiofrequency radiation

Some historical aspects on late lessons from early warnings on cancer risks with lost time for prevention are discussed. One current example is the cancer-causing effect from radiofrequency (RF) radiation. Studies since decades have shown increased human cancer risk. The fifth generation, 5G, for wireless communication is about to be implemented world-wide despite no comprehensive investigations of potential risks to human health and the environment. This has created debate on this technology among concerned people in many countries. In an appeal to EU in September 2017, currently endorsed by more than 400 scientists and medical doctors, a moratorium on the 5G deployment was required until proper scientific evaluation of negative consequences has been made (www.5Gappeal.eu). That request has not been taken seriously by EU. Lack of proper unbiased risk evaluation of the 5G technology makes adverse effects impossible to be foreseen. This disregard is exemplified by the recent report from the International Commission on non-ionizing radiation protection (ICNIRP) whereby only thermal (heating) effects from RF radiation are acknowledged despite a large number of reported non-thermal effects. Thus, no health effects are acknowledged by ICNIRP for non-thermal RF electromagnetic fields in the range of 100 kHz-300 GHz. Based on results in three case-control studies on use of wireless phones we present preventable fraction for brain tumors. Numbers of brain tumors of not defined type were found to increase in Sweden, especially in the age group 20-39 years in both genders, based on the Swedish Inpatient Register. This may be caused by the high prevalence of wireless phone use among children and in adolescence taking a reasonable latency period and the higher vulnerability to RF radiation among young persons.

Wartime toxin exposure: recognising the silent killer

Wartime toxin exposures have been implicated in the genesis of malignancy in war veterans. Agent Orange, one toxin among many, has been linked to malignancy and the subcomponent phenoxyacetic acid has been associated with soft tissue sarcomas (STSs). This case demonstrates the association between a wartime toxin exposure (Agent Orange) and subsequent cancer development. Ultimately, we aim to highlight the importance of simple, specific questions in the patient history to account for previous wartime toxin exposures.

Does 2,4-dichlorophenoxyacetic acid (2,4-D) induce genotoxic effects in tissue cultured Allium roots?

2,4-Dichlorophenoxyacetic acid (2,4-D) is a synthetic plant growth regulator that is highly toxic to most broad leaved plants and relatively nontoxic to monocotyledonous plants; is frequently used as weed killer. The study aimed to investigate cytogenetic effects of different concentrations of 2,4-D (0.67, 1.34, 2.01, 2.68, 3.35 and 4.02 mg/L) on Allium cepa bulblets' root tips treated for 24 and 48 h. The results showed six types of structural aberrations: C-mitosis, stickiness, laggards, bridges, fragments and multipolarity that varied numerically compared to control. It significantly affected mitotic index (MI) at 24 and 48 h treatment. In the Allium test, MI increased significantly at three lower concentrations (0.67, 1.34, 2.01 mg/L) after treatment with 2,4-D for 24 h and decreased significantly at higher concentration. Whereas, 2,4-D treatment for 48 h increased MI at all concentrations with significantly decreased MI at the highest concentration. The experiment was extended using comet test that did not reveal significant difference among treatments except for application of 4.02 mg/L 2,4-D for 48 h; where cell damages were verified by comet test. Rest of the concentrations for any duration of time were not damaging and toxic to cells. The results showed, visible mitodepressive action of 4.02 mg/L 2,4-D when treated for 48 h that had tendency to become toxic if the roots had been in touch with 2,4-D for a longer time.

An Italian population-based case-control study on the association between farming and cancer: Are pesticides a plausible risk factor?

This population-based case-control study investigated the association between farming (a proxy for pesticide exposure) and cancer in the Vercelli suburban area (northwest Italy). The residents, aged 25 to 79 years, in the above-mentioned area during the period 2002-2009 were considered. Cases were all the first hospital admissions for cancer. Controls were all the subjects not included in the cases and not excluded from the study. Cases and controls were classified according to whether they occupationally resulted farmers or nonfarmers during the period 1965-2009. Cancer odds ratios (ORs) between farmers and nonfarmers were calculated with generalized linear mixed models adjusted by gender and age. Farmers showed higher odds for all cancers (OR=1.459; p < .001), nonmelanoma skin cancer, colorectal cancer, and breast cancer. The results suggest a plausible association between pesticide exposure and cancer occurrence.

Increased incidence of malignant melanoma and other rare cutaneous cancers in the setting of chronic lymphocytic leukemia

BACKGROUND

Patients with chronic lymphocytic leukemia (CLL), small lymphocytic lymphoma (SLL), or non-Hodgkin lymphoma (NHL) are at increased risk for the development of skin malignancies.

OBJECTIVES

This study was conducted to estimate the incidences of rare skin malignancies in patients with CLL/SLL or NHL.

METHODS

Patients with a diagnosis of CLL/SLL or NHL recorded in the Surveillance, Epidemiology and End Results (SEER) database during 1992-2007 were identified. Diagnoses of specific skin malignancies were identified from SEER files.

RESULTS

During 1992-2007, a total of 128,674 patients with first diagnoses of CLL/SLL or NHL were recorded in SEER; 4743 were excluded because follow-up data were unavailable. Among the remaining 123,931 patients, 28,964 had CLL/SLL and 94,967 had NHL. Standardized incidence ratios (SIRs) for invasive malignant melanoma, Merkel cell carcinoma, malignant fibrous histiocytoma, dermatofibrosarcoma protuberans, Kaposi's sarcoma, and sebaceous carcinoma were 2.3, 8.2, 3.6, 2.5, 2.9, and 1.4, respectively, in CLL/SLL patients and 1.6, 3.2, 1.5, 1.3, 17.6, and 0.8, respectively, in NHL patients. When invasive melanoma was stratified by patient age and sex, the highest SIR (17.8) was found in men aged 0-49 years with CLL (P < 0.001).

CONCLUSIONS

Patients with CLL/SLL or NHL have a higher risk for the subsequent development of rare skin cancers. Given the more aggressive nature of these malignancies in this setting, regular monitoring for the development and prompt treatment of cutaneous malignancy is prudent in patients with NHL and particularly in patients with CLL. Regular use of sun protection may decrease the morbidity associated with skin cancer in this immunosuppressed population.

Gastrointestinal stromal tumors: a case-only analysis of single nucleotide polymorphisms and somatic mutations

Background

Gastrointestinal stromal tumors are rare soft tissue sarcomas that typically develop from mesenchymal cells with acquired gain-in-function mutations in KIT or PDGFRA oncogenes. These somatic mutations have been well-characterized, but little is known about inherited genetic risk factors. Given evidence that certain susceptibility loci and carcinogens are associated with characteristic mutations in other cancers, we hypothesized that these signature KIT or PDGFRA mutations may be similarly fundamental to understanding gastrointestinal stromal tumor etiology. Therefore, we examined associations between 522 single nucleotide polymorphisms and seven KIT or PDGFRA tumor mutations types. Candidate pathways included dioxin response, toxin metabolism, matrix metalloproteinase production, and immune and inflammatory response.

Methods

We estimated odds ratios and 95% confidence intervals for associations between each candidate SNP and tumor mutation type in 279 individuals from a clinical trial of adjuvant imatinib mesylate. We used sequence kernel association tests to look for pathway-level associations.

Results

One variant, rs1716 on ITGAE, was significantly associated with KIT exon 11 non-codon 557–8 deletions (odds ratio = 2.86, 95% confidence interval: 1.71-4.78) after adjustment for multiple comparisons. Other noteworthy associations included rs3024498 (IL10) and rs1050783 (F13A1) with PDGFRA mutations, rs2071888 (TAPBP) with wild type tumors and several matrix metalloproteinase SNPs with KIT exon 11 codon 557–558 deletions. Several pathways were strongly associated with somatic mutations in PDGFRA, including defense response (p = 0.005) and negative regulation of immune response (p = 0.01).

Conclusions

This exploratory analysis offers novel insights into gastrointestinal stromal tumor etiology and provides a starting point for future studies of genetic and environmental risk factors for the disease.

Detection of herbicides in the urine of pet dogs following home lawn chemical application

Exposure to herbicide-treated lawns has been associated with significantly higher bladder cancer risk in dogs. This work was performed to further characterize lawn chemical exposures in dogs, and to determine environmental factors associated with chemical residence time on grass. In addition to concern for canine health, a strong justification for the work was that dogs may serve as sentinels for potentially harmful environmental exposures in humans. Experimentally, herbicides [2,4-dichlorophenoxyacetic acid (2,4-D), 4-chloro-2-methylphenoxypropionic acid (MCPP), dicamba] were applied to grass plots under different conditions (e.g., green, dry brown, wet, and recently mowed grass). Chemicals in dislodgeable residues were measured by LC-MS at 0.17, 1, 24, 48, 72 h post treatment. In a separate study, 2,4-D, MCPP, and dithiopyr concentrations were measured in the urine of dogs and in dislodgeable grass residues in households that applied or did not apply chemicals in the preceding 48 h. Chemicals were measured at 0, 24, and 48 h post application in treated households and at time 0 in untreated control households. Residence times of 2,4-D, MCPP, and dicamba were significantly prolonged (P<0.05) on dry brown grass compared to green grass. Chemicals were detected in the urine of dogs in 14 of 25 households before lawn treatment, in 19 of 25 households after lawn treatment, and in 4 of 8 untreated households. Chemicals were commonly detected in grass residues from treated lawns, and from untreated lawns suggesting chemical drift from nearby treated areas. Thus dogs could be exposed to chemicals through contact with their own lawn (treated or contaminated through drift) or through contact with other grassy areas if they travel. The length of time to restrict a dog's access to treated lawns following treatment remains to be defined. Further study is indicated to assess the risks of herbicide exposure in humans and dogs.

Gastrointestinal stromal tumors, somatic mutations and candidate genetic risk variants

Gastrointestinal stromal tumors (GISTs) are rare but treatable soft tissue sarcomas. Nearly all GISTs have somatic mutations in either the KIT or PDGFRA gene, but there are no known inherited genetic risk factors. We assessed the relationship between KIT/PDGFRA mutations and select deletions or single nucleotide polymorphisms (SNPs) in 279 participants from a clinical trial of adjuvant imatinib mesylate. Given previous evidence that certain susceptibility loci and carcinogens are associated with characteristic mutations, or "signatures" in other cancers, we hypothesized that the characteristic somatic mutations in the KIT and PDGFRA genes in GIST tumors may similarly be mutational signatures that are causally linked to specific mutagens or susceptibility loci. As previous epidemiologic studies suggest environmental risk factors such as dioxin and radiation exposure may be linked to sarcomas, we chose 208 variants in 39 candidate genes related to DNA repair and dioxin metabolism or response. We calculated adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for the association between each variant and 7 categories of tumor mutation using logistic regression. We also evaluated gene-level effects using the sequence kernel association test (SKAT). Although none of the association p-values were statistically significant after adjustment for multiple comparisons, SNPs in CYP1B1 were strongly associated with KIT exon 11 codon 557-8 deletions (OR = 1.9, 95% CI: 1.3-2.9 for rs2855658 and OR = 1.8, 95% CI: 1.2-2.7 for rs1056836) and wild type GISTs (OR = 2.7, 95% CI: 1.5-4.8 for rs1800440 and OR = 0.5, 95% CI: 0.3-0.9 for rs1056836). CYP1B1 was also associated with these mutations categories in the SKAT analysis (p = 0.002 and p = 0.003, respectively). Other potential risk variants included GSTM1, RAD23B and ERCC2. This preliminary analysis of inherited genetic risk factors for GIST offers some clues about the disease's genetic origins and provides a starting point for future candidate gene or gene-environment research.

Risk factors for gliomas. An extensive review

Primary brain tumors consist are a heterogenic group of malignancies. Gliomas represent subtypes which include all tumors arising from glial cells. The risk factors for gliomas are until today unclear. The aim of this study was to summarize all possible connections between suspected risk factors and glial brain tumors.

Long-term toxicology and carcinogenicity of 2,4,6-trichlorophenol

Carcinogenesis bioassays were conducted by giving 2,4,6-trichlorophenol [2,4,6-TCP] in feed to groups of 50 male and female Fischer rats and male B6C3F1 mice for two years. Dietary concentrations were 0 [20/group], 5000 [0.5%], or 10,000 [1%] ppm. Female mice began with 10,000 and 20,000 ppm but after 38 weeks were lowered due to reduced body weights to 2500 and 5000 ppm for 67 weeks; exposures averaged 5200 and 10,400 ppm. Adverse effects at two years were leukocytosis and monocytosis of peripheral blood and hyperplasia of bone marrow in both sexes of rats. In mice, liver toxicity, including individual liver cell abnormalities, focal areas of cellular alteration, and focal and nodular areas of hyperplasia were commonly present. Regarding carcinogenic activity, TCP caused leukemias/lymphomas in male rats, and possibly in female rats and female mice as well, and induced liver tumors in male and female mice. Using NTP categories of evidence indicates 'clear evidence of carcinogenicity' for male rats [hematopoietic system tumors]; 'equivocal evidence of carcinogenicity' for female rats [hematopoietic system tumors]; 'clear evidence of carcinogenicity' for male and female mice [liver tumors].

Nutrition in complementary and alternative medicine

OBJECTIVES

To review the prevalence of nutrition-related complementary and alternative medicine (CAM) used by patients with cancer, to discuss nutrition issues commonly raised by cancer survivors, and to describe how the oncology health care practitioner can best address these issues.

DATA SOURCES

Journal articles, texts, and personal oncology nutrition clinical experience.

CONCLUSION

The interest in and use of special diets and nutrition-related CAM is prevalent in oncology patients. While some nutrition interventions may offer benefit, not all are without risk.

IMPLICATIONS FOR NURSING PRACTICE

Every patient must be assessed for the use of special diets and nutrition-related CAM, any use must be documented, and the person counseled about the pros and cons of these approaches.

Soft-tissue sarcoma and pesticides exposure in men: results of a Canadian case-control study

OBJECTIVES

The objective was to investigate the putative associations of specific pesticides with soft-tissue sarcoma (STS).

METHODS

A Canadian population-based case-control study conducted in six provinces was used in this analysis. The study design consisted of two stages: a self-administered postal questionnaire and a telephone interview for those reporting pesticides exposure of 10 hours per year or more; and a 15% random sample of the remainder. Conditional logistic regression was used to fit the statistical models.

RESULTS

A positive history of cancer among first-degree relatives and exposure to aldrin and diazinon were statistically significant independent predictors of an increased risk for STS, whereas diagnosis of whopping cough lowered the risk of STS.

CONCLUSIONS

The incidence of STS was associated with specific insecticides after adjustment for other independent predictors.

Plasma levels of polychlorinated biphenyls, non-Hodgkin lymphoma, and causation

Polychlorinated biphenyls (PCBs) are synthetic chlorinated hydrocarbons that have extensively polluted the environment and bioaccumulated in the food chain. PCBs have been deemed to be probable carcinogens by the Environmental Protection Agency, and exposure to high levels of PCBs has been consistently linked to increased risk of non-Hodgkin lymphoma (NHL). In the present article we present a forensic epidemiologic evaluation of the causal relationship between NHL and elevated PCB levels via application of the Bradford-Hill criteria. Included in the evaluation is a meta-analysis of the results of previously published case-control studies in order to assess the strength of association between NHL and PCBs, resulting in an odds ratio in which the lowest percentile PCB concentration (quartile, quintile, or tertile) has been compared with the highest percentile concentration in the study groups. The weight-adjusted odds ratio for all PCB congeners was 1.43 with a 95% confidence interval of 1.31 to 1.55, indicating a statistically significant causal association with NHL. Because of the lack of an unexposed comparison group, a rationale for the use of a less than 2.0 relative risk causal contribution threshold is presented herein, including an ecologic analysis of NHL incidence and PCB accumulation (as measured by sales volume) over time. The overall results presented here indicate a strong general causal association between NHL and PCB exposure.

Is the fear of dioxin cancer more harmful than dioxin?

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a proven animal carcinogen. Occupational cohorts with the highest exposures imply that there is a small risk of all cancers combined, but it is difficult to pinpoint the confounding effect of the main chemicals. Studies after major accidents do not unequivocally confirm this risk. The risks to populations at the current dioxin levels seem trivial if present at all. There is increasing evidence that the aryl hydrocarbon receptor (AhR), i.e. the so called "dioxin receptor", is a physiological transcription factor exerting important functions in the body. Consequently a certain level of AhR activation may be beneficial rather than harmful. This challenges the wisdom of excessive regulation of dioxin levels in certain foods and nutrients. This could pose indirect nutritional risks, in fact being more harmful than even the worst case predictions of the putative cancer risks attributable to dioxins.

Soft tissue sarcoma diagnosed subsequent to lymphoma is associated with prior radiotherapy and decreased survival

BACKGROUND

Cancer survivors are at increased risk for second malignancies, and vigilance is thus required. The authors sought to determine whether there was an association among lymphoma, sarcoma, and the associated treatments for these diseases.

METHODS

From the authors' prospective soft tissue sarcoma (STS) database of 8240 patients, they identified 112 patients with STS and lymphoma treated from 1982 to 2009 who had complete follow-up data. They examined the importance of the initial diagnosis in patients with both STS and lymphoma, in addition to determining the role of radiation therapy, a known inducer of sarcoma.

RESULTS

Review of their sarcoma, gastric, urology, breast, and gynecology databases revealed that lymphoma (95%) or leukemia (5%) occurred in 1.6% of STS patients in comparison to 0.5% of patients in the other databases (P < .01; odds ratio, 3.1; 95% confidence interval, 2.6-3.8). Patients diagnosed with STS only were more likely to die of disease at 10 years compared with those with STS and lymphoma (P = .006), but this difference was not significant when patients presenting with recurrence or metastases were excluded. Among patients with lymphoma and STS, lymphoma was the first diagnosis in 71% of patients. Median survival after STS diagnosis was shorter when lymphoma was the initial diagnosis (67 vs 170 months, P = .002), and these patients were more likely to have radiation-associated STS (44% vs 3%, P < .001).

CONCLUSIONS

There was a 3-fold higher incidence of lymphoma in STS patients compared with other solid tumors. The poor prognosis of those diagnosed with both STS and lymphoma was most likely a consequence of prior irradiation.

Mortality of US pentachlorophenol production workers through 2005

A cohort of 2122 US pentachlorophenol (PCP) production workers from four plants in the National Institute for Occupational Safety and Health Dioxin Registry was exposed to PCP and to polychlorinated dibenzo-p-dioxin and dibenzofuran contaminants of PCP production. A subcohort of 720 was also exposed to 2,3,7,8-tetrachlorodibenzodioxin, a contaminant of trichlorophenol (TCP) while using TCP or a TCP derivative. PCP and several production contaminants have been implicated as animal carcinogens. A priori hypotheses were that the cohort would have elevated standardized mortality ratios (SMRs) for aplastic anemia, soft-tissue sarcoma, and non-Hodgkin lymphoma, as suggested by human studies, and for leukemia and liver, adrenal, thyroid, and parathyroid cancer, as suggested by animal studies. From 1940 to 2005 1165 deaths occurred with an overall SMR of 1.01 [95% confidence limits (CI), 0.95-1.07]. Overall cancer mortality (326 deaths, SMR 1.17, CI 1.05-1.31) was in statistically significant excess. There were excess deaths for trachea, bronchus and lung cancers (126 deaths, SMR 1.36, CI 1.13-1.62), non-Hodgkin lymphoma (17 deaths, SMR 1.77, CI 1.03-2.84), chronic obstructive pulmonary disease (63 deaths, SMR 1.38, CI 1.06-1.77), and medical complications (5 deaths, SMR 3.52, CI 1.14-8.22). In race- and sex-specific analyses, white males had increased non-Hodgkin lymphoma mortality (17 deaths, SMR 1.98, CI 1.15-3.17) and males of other races had increased leukemia mortality (four deaths, SMR 4.57, CI 1.25-11.7). The excess of cancers of a priori interest, non-Hodgkin lymphoma and leukemia, provide some support for the carcinogenicity of PCP, however, further studies with more detailed exposure assessment are needed.

Bibliography. Current world literature

This bibliography is compiled by clinicians from the journals listed at the end of this publication. It is based on literature entered into our database between 1 November 2007 and 31 October 2008 (articles are generally added to the database about two and a half months after publication). In addition, the bibliography contains every paper annotated by reviewers; these references were obtained from a variety of bibliographic databases and published between the beginning of the review period and the time of going to press. The bibliography has been grouped into topics that relate to the reviews in this issue.

Rare skin cancer: a population-based cancer registry descriptive study of 151 consecutive cases diagnosed between 1980 and 2004

BACKGROUND

There are few epidemiological data available on rare skin cancer, including Merkel cell carcinoma, Paget's disease, adnexal carcinoma, and sarcoma. We conducted this study to investigate the epidemiology of rare skin cancer diagnosed in the department of Doubs from 1980 to 2004.

METHODS

Data were collected from a population-based cancer registry from 1980 to 2004. Diagnosis was based on the 3(rd) edition of the International Classification of Diseases for Oncology. The incidence rates were standardized on world population.

RESULTS

One hundred and fifty one patients were investigated (88 women and 63 men). Median age for the diagnosed disease was 63 years. The standardized incidence rate was 0.82/100 000 person-year (95% CI = 0.68-0.96) and increased from 0.25 in 1980-1984 to 1.50 in 2000-2004. Fifty nine cases (39%) were sarcomas, 35 (23%) adnexal carcinomas, 27 (18%) Merkel cell carcinoma and 27 (18%) Paget's disease. The standardized incidence rates were 0.37/100 000 (0.27-0.47) for sarcomas, 0.16 (0.10-0.22) for adnexal tumors, 0.13 (0.08-0.18) for Merkel cell carcinoma, and 0.15 (0.09-0.21) for Paget's disease.

CONCLUSIONS

Our results based on a population-based cancer registry showed an increase of the standardized incidence rate for all types of rare skin tumors. These results may be useful when considering the growing interest in rare diseases in identifying risk factors and planning scientific research programmes.