Cancer Risks

Avila-Vazquez et al., 2015

Medardo Avila-Vazquez, Agustina Etchegoyen, Eduardo Maturano and Luciana Ruderman, “Cancer and detrimental reproductive effects in an Argentine agricultural community environmentally exposed to glyphosate,” The Journal of Biological Physics and Chemistry, 2015, 15:3, DOI: 10.4024/09VA15A.jbpc.15.03


Argentina utilizes about 200 000 tonnes of glyphosate for its agriculture each year. People living near the fields treated with glyphosate often mention an increase in cancer and reproductive alterations. In Monte Maiz, an agricultural settlement with approximate population 8000, we conducted an environmental test assessing water, soil and particulate material contamination as well as an epidemiological study to detect and locate cases of cancer, abortion and genetic abnormality. The site utilizes annually 650 tonnes of glyphosate applied over an area of 65 000 ha. The glyphosate is concentrated and prepared for dispersal in the settlement. We detected glyphosate in particulate material and grain husks and it was found to be present at an even higher concentration on the ground in the village than in the surrounding rural area. The rate of spontaneous abortion in Monte Maiz is three times higher than the national average and the rate of occurrence of genetic abnormality is about twice the national average. Cancer occurrence is between two and three times the reference values for the entire nation with regard to incidence, prevalence and mortality. Although it is of course impossible to establish direct causality, the indicators that emerge from the correlated variables strongly suggest a public health problem of significant proportions, requiring immediate attention.


Avila-Vazquez et al., 2017

Medardo Avila-Vazquez, Eduardo Maturano, Agustina Etchegoyen, Flavia Silvina Difilippo, Bryan Maclean, “Association between Cancer and Environmental Exposure to Glyphosate,” International Journal of Clinical Medicine, 2017, 8:2, DOI: 10.4236/ijcm.2017.82007


BACKGROUND: Argentina, Brazil, Paraguay and Uruguay farm transgenic seeds glyphosate resistant. Argentina annually utilizes 240,000 tonnes of glyphosate in agriculture. A change in the profile of morbidity and mortality is perceived in agricultural areas; cancer seems to prevail. Monte Maíz is a typical argentine agricultural town with 8000 inhabitants; the Mayor and residents of Monte Maiz requested an environmental health study due to perceived increase in cancer frequencies.

METHODS: An exploratory ecological study was developed to assess the urban environmental contamination and the frequencies and distribution of cancer through an environmental analysis of pollution sources including measurements of pesticides in water, soil and grain dust, and a cross-sectional study of cancer patients that explore associations with different variables.

RESULTS: Glyphosate was detected in soil and grain dust and was found to be at an even higher concentration in the village soil than in the rural area. 650 tonnes are used annually in the region and manipulated inner town. We do not find other relevant sources of pollution. Cancer incidence, prevalence, and mortality are between two and three times higher than the reference values (Globocan 2012, WHO) for the entire nation (706/100,000 persons vs. 217/100,000; 2123/100,000 persons vs. 883.82/100,000 and 383/100,000 persons vs. 115.13/100,000, respectively).

CONCLUSION: This study detects high glyphosate pollution in association with increased frequencies of cancer in a typical argentine agricultural village, and by design, cannot make claims of causality. Other study designs are required, but if we corroborate the concrescence of high exposure to glyphosate and cancer. FULL TEXT

Band et al., 2011

Band PR, Abanto Z, Bert J, Lang B, Fang R, Gallagher RP, Le ND., “Prostate cancer risk and exposure to pesticides in British Columbia farmers,” Prostate, 2011, 71:2, DOI: 10.1002/pros.21232.


BACKGROUND: Several epidemiologic studies have reported an increased risk of prostate cancer among farmers. Our aim was to assess the risk of developing prostate cancer in relation to exposure to specific active compounds in pesticides.

METHOD: A case-control approach was used with 1,516 prostate cancer patients and 4,994 age-matched internal controls consisting of all other cancer sites excluding lung cancer and cancers of unknown primary site. Lifetime occupational history was obtained through a self-administered questionnaire and used in conjunction with a job exposure matrix to estimate the participants’ lifetime cumulative exposure to approximately 180 active compounds in pesticides. Conditional logistic regression was used to assess prostate cancer risk, adjusting for potential confounding variables and effect modifiers. These include age, ethnicity, alcohol consumption, smoking, education, and proxy respondent.

RESULTS AND CONCLUSIONS: The significant association between prostate cancer risk and exposure to DDT (OR = 1.68; 95% CI: 1.04-2.70 for high exposure), simazine (OR = 1.89; 95% CI: 1.08-3.33 for high exposure), and lindane (OR = 2.02; 95% CI: 1.15-3.55 for high exposure) is in keeping with those previously reported in the literature. We also observed a significant excess risk for several active ingredients that have not been previously reported in the literature such as dichlone, dinoseb amine, malathion, endosulfan, 2,4-D, 2,4-DB, and carbaryl. Some findings in our study were not consistent with those reported in the literature, including captan, dicamba, and diazinon. It is possible that these findings showed a real association and the inconsistencies reflected differences of characteristics between study populations.

Benbrook, 2016c

John Peterson Myers, Michael N. Antoniou, Bruce Blumberg, Lynn Carroll, Theo Colborn, Lorne G. Everett, Michael Hansen, Philip J. Landrigan, Bruce P. Lanphear, Robin Mesnage, Laura N. Vandenberg, Frederick S. vom Saal, Wade V. Welshons and Charles M. Benbrook. “Concerns over use of glyphosate-based herbicides and risks associated with exposures: a consensus statement,” Environmental Health, 2016, 15:19, DOI: 10.1186/s12940-016-0117-0.


The broad-spectrum herbicide glyphosate (common trade name “Roundup”) was first sold to farmers in 1974. Since the late 1970s, the volume of glyphosate-based herbicides (GBHs) applied has increased approximately 100-fold. Further increases in the volume applied are likely due to more and higher rates of application in response to the widespread emergence of glyphosate-resistant weeds and new, pre-harvest, dessicant use patterns. GBHs were developed to replace or reduce reliance on herbicides causing well-documented problems associated with drift and crop damage, slipping efficacy, and human health risks. Initial industry toxicity testing suggested that GBHs posed relatively low risks to non-target species, including mammals, leading regulatory authorities worldwide to set high acceptable exposure limits. To accommodate changes in GBH use patterns associated with genetically engineered, herbicide-tolerant crops, regulators have dramatically increased tolerance levels in maize, oilseed (soybeans and canola), and alfalfa crops and related livestock feeds. Animal and epidemiology studies published in the last decade, however, point to the need for a fresh look at glyphosate toxicity. Furthermore, the World Health Organization’s International Agency for Research on Cancer recently concluded that glyphosate is “probably carcinogenic to humans.” In response to changing GBH use patterns and advances in scientific understanding of their potential hazards, we have produced a Statement of Concern drawing on emerging science relevant to the safety of GBHs. Our Statement of Concern considers current published literature describing GBH uses, mechanisms of action, toxicity in laboratory animals, and epidemiological studies. It also examines the derivation of current human safety standards. We conclude that: (1) GBHs are the most heavily applied herbicide in the world and usage continues to rise; (2) Worldwide, GBHs often contaminate drinking water sources, precipitation, and air, especially in agricultural regions; (3) The half-life of glyphosate in water and soil is longer than previously recognized; (4) Glyphosate and its metabolites are widely present in the global soybean supply; (5) Human exposures to GBHs are rising; (6) Glyphosate is now authoritatively classified as a probable human carcinogen; (7) Regulatory estimates of tolerable daily intakes for glyphosate in the United States and European Union are based on outdated science. We offer a series of recommendations related to the need for new investments in epidemiological studies, biomonitoring, and toxicology studies that draw on the principles of endocrinology to determine whether the effects of GBHs are due to endocrine disrupting activities. We suggest that common commercial formulations of GBHs should be prioritized for inclusion in government-led toxicology testing programs such as the U.S. National Toxicology Program, as well as for biomonitoring as conducted by the U.S. Centers for Disease Control and Prevention.  FULL TEXT

Cabello et al., 2001

Gertrudis Cabello, Mario Valenzuela, Arnaldo Vilaxa, Viviana Durán, Isolde Rudolph, Nicolas Hrepic, and Gloria Calaf, “A Rat Mammary Tumor Model Induced by the Organophosphorous Pesticides Parathion and Malathion, Possibly through Acetylcholinesterase Inhibition,” Environmental Health Perspectives, 2001, 109:5.


Environmental chemicals may be involved in the etiology of breast cancers. Many studies have addressed the association between cancer in humans and agricultural pesticide exposure. Organophosphorous pesticides have been used extensively to control mosquito plagues. Parathion and malathion are organophosphorous pesticides extensively used to control a wide range of sucking and chewing pests of field crops, fruits, and vegetables. They have many structural similarities with naturally occurring compounds, and their primary target of action in insects is the nervous system; they inhibit the release of the enzyme acetylcholinesterase at the synaptic junction. Eserine, parathion, and malathion are cholinesterase inhibitors responsible for the hydrolysis of body choline esters, including acetylcholine at cholinergic synapses. Atropine, a parasympatholytic alkaloid, is used as an antidote to acetylcholinesterase inhibitors. The aim of this study was to examine whether pesticides were able to induce malignant transformation of the rat mammary gland and to determine whether alterations induced by these substances increase the cholinergic activation influencing such transformation. These results showed that eserine, parathion, and malathion increased cell proliferation of terminal end buds of the 44-day-old mammary gland of rats, followed by formation of 8.6, 14.3, and 24.3% of mammary carcinomas, respectively, after about 28 months. At the same time, acetylcholinesterase activity decreased in the serum of these animals from 9.78 +/- 0.78 U/mL in the control animals to 3.05 +/- 0.06 U/mL; 2.57 +/- 0.15 U/mL; and 3.88 +/- 0.44 U/mL in the eserine-, parathion-, and malathion-treated groups, respectively. However, atropine alone induced a significant (p < 0.05) decrease in the acetylcholinesterase activity from the control value of 9.78 +/- 0.78 to 4.38 +/- 0.10 for atropine alone, to 1.32 +/- 0.06 for atropine in combination with eserine, and 2.39 +/- 0.29 for atropine with malathion, and there was no mammary tumor formation. These results indicate that organophosphorous pesticides induce changes in the epithelium of mammary gland influencing the process of carcinogenesis, and such alterations occur at the level of nervous system by increasing the cholinergic stimulation. FULL TEXT

Clausing et al., 2018

Clausing, P., Robinson, C., & Burtscher-Schaden, H., “Pesticides and public health: an analysis of the regulatory approach to assessing the carcinogenicity of glyphosate in the European Union,” Journal of Epidemiology and Community Health, 2018, 72(8), 668-672, DOI:10.1136/jech-2017-209776.


The present paper scrutinises the European authorities’ assessment of the carcinogenic hazard posed by glyphosate based on Regulation (EC) 1272/2008. We use the authorities’ own criteria as a benchmark to analyse their weight of evidence (WoE) approach. Therefore, our analysis goes beyond the comparison of the assessments made by the European Food Safety Authority and the International Agency for Research on Cancer published by others. We show that not classifying glyphosate as a carcinogen by the European authorities, including the European Chemicals Agency, appears to be not consistent with, and in some instances, a direct violation of the applicable guidance and guideline documents. In particular, we criticise an arbitrary attenuation by the authorities of the power of statistical analyses; their disregard of existing dose-response relationships; their unjustified claim that the doses used in the mouse carcinogenicity studies were too high and their contention that the carcinogenic effects were not reproducible by focusing on quantitative and neglecting qualitative reproducibility. Further aspects incorrectly used were historical control data, multisite responses and progression of lesions to malignancy. Contrary to the authorities’ evaluations, proper application of statistical methods and WoE criteria inevitably leads to the conclusion that glyphosate is ‘probably carcinogenic’ (corresponding to category 1B in the European Union). FULL TEXT

Cocco et al., 2013

Cocco, Pierluigi, Satta, Giannina, Dubois, Stefania, Pili, Claudia, Pilleri, Michela, Zucca, Mariagrazia, ‘t Mannetje, Andrea Martine, Becker, Nikolaus, Benavente, Yolanda, de Sanjosé, Silvia, Foretova, Lenka, Staines, Anthony, Maynadié, Marc, Nieters, Alexandra, Brennan, Paul, Miligi, Lucia, Ennas, Maria Grazia, & Boffetta, Paolo, “Lymphoma risk and occupational exposure to pesticides: results of the EPILYMPH study,” Occupational and Environmental Medicine, 2013, 70(2), 91, DOI: 10.1136/oemed-2012-100845.


OBJECTIVES: We investigated the role of occupational exposure to specific groups of agrochemicals in the aetiology of lymphoma overall, B cell lymphoma and its most prevalent subtypes.

METHODS: In 1998–2003, 2348 incident lymphoma cases and 2462 controls were recruited to the EPILYMPH case-control study in six European countries. A detailed occupational history was collected in cases and controls. Job modules were applied for farm work including specific questions on type of crop, farm size, pests being treated, type and schedule of pesticide use. In each study centre, industrial hygienists and occupational experts assessed exposure to specific groups of pesticides and individual compounds with the aid of agronomists. We calculated the OR and its 95% CI associated with lymphoma and the most prevalent lymphoma subtypes with unconditional logistic regression, adjusting for age, gender, education and centre.

RESULTS: Risk of lymphoma overall, and B cell lymphoma was not elevated, and risk of chronic lymphocytic leukaemia (CLL) was elevated amongst those ever exposed to inorganic (OR=1.6, 95% CI 1.0 to 2.5) and organic pesticides (OR=1.5, 95% CI 1.0 to 2.1). CLL risk was highest amongst those ever exposed to organophosphates (OR=2.7, 95% CI 1.2 to 6.0). Restricting the analysis to subjects most likely exposed, no association was observed between pesticide use and risk of B cell lymphoma.

CONCLUSIONS: Our results provide limited support to the hypothesis of an increase in risk of specific lymphoma subtypes associated with exposure to pesticides.

Cohn et al., 2007

Cohn BA, Wolff MS, Cirillo PM, Sholtz RI, “DDT and breast cancer in young women: new data on the significance of age at exposure,” Environmental  Health Perspectives, 2007, 115:10.


BACKGROUND: Previous studies of DDT and breast cancer assessed exposure later in life when the breast may not have been vulnerable, after most DDT had been eliminated, and after DDT had been banned.

OBJECTIVES: We investigated whether DDT exposure in young women during the period of peak DDT use predicts breast cancer.

METHODS: We conducted a prospective, nested case-control study with a median time to diagnosis of 17 years using blood samples obtained from young women during 1959-1967. Subjects were members of the Child Health and Development Studies, Oakland, California, who provided blood samples 1-3 days after giving birth (mean age, 26 years). Cases (n = 129) developed breast cancer before the age of 50 years. Controls (n = 129) were matched to cases on birth year. Serum was assayed for p,p’-DDT, the active ingredient of DDT; o,p’-DDT, a low concentration contaminant; and p,p’-DDE, the most abundant p,p’-DDT metabolite.

RESULTS: High levels of serum p,p’-DDT predicted a statistically significant 5-fold increased risk of breast cancer among women who were born after 1931. These women were under 14 years of age in 1945, when DDT came into widespread use, and mostly under 20 years as DDT use peaked. Women who were not exposed to p,p’-DDT before 14 years of age showed no association between p,p’-DDT and breast cancer (p = 0.02 for difference by age).

CONCLUSIONS: Exposure to p,p’-DDT early in life may increase breast cancer risk. Many U.S. women heavily exposed to DDT in childhood have not yet reached 50 years of age. The public health significance of DDT exposure in early life may be large.  FULL TEXT

Cohn et al., 2015

Cohn BA, La Merrill M, Krigbaum NY, Yeh G, Park JS, Zimmermann L, Cirillo PM, “DDT Exposure in Utero and Breast Cancer,” Journal of Clinical Endocrinology and Metabolism, 2015, 100:8, doi: 10.1210/jc.2015-1841.


CONTEXT: Currently no direct evidence links in utero dichlorodiphenyltrichloroethane (DDT) exposure to human breast cancer. However, in utero exposure to another xenoestrogen, diethylstilbestrol, predicts an increased breast cancer risk. If this finding extends to DDT, it could have far-reaching consequences. Many women were heavily exposed in utero during widespread DDT use in the 1960s. They are now reaching the age of heightened breast cancer risk. DDT exposure persists and use continues in Africa and Asia without clear knowledge of the consequences for the next generation.

HYPOTHESIS: In utero exposure to DDT is associated with an increased risk of breast cancer.

DESIGN: This was a case-control study nested in a prospective 54-year follow-up of 9300 daughters in the Child Health and Development Studies pregnancy cohort (n = 118 breast cancer cases, diagnosed by age 52 y and 354 controls matched on birth year).

SETTING AND PARTICIPANTS: Kaiser Foundation Health Plan members who received obstetric care in Alameda County, California, from 1959 to 1967, and their adult daughters participated in the study.

MAIN OUTCOME MEASURE: Daughters’ breast cancer diagnosed by age 52 years as of 2012 was measured.

RESULTS: Maternal o,p’-DDT predicted daughters’ breast cancer (odds ratio fourth quartile vs first = 3.7, 95% confidence interval 1.5-9.0). Mothers’ lipids, weight, race, age, and breast cancer history did not explain the findings.

CONCLUSIONS: This prospective human study links measured DDT exposure in utero to risk of breast cancer. Experimental studies are essential to confirm results and discover causal mechanisms. Findings support classification of DDT as an endocrine disruptor, a predictor of breast cancer, and a marker of high risk.  FULL TEXT

Davoren and Schiestl, 2018

Davoren, Michael J, & Schiestl, Robert H., “Glyphosate-based herbicides and cancer risk: a post-IARC decision review of potential mechanisms, policy and avenues of research,” Carcinogenesis,  2018, 39:10, 1207-1215. DOI:10.1093/carcin/bgy105.


Since its initial sales in the 1970s, the herbicide glyphosate attained widespread use in modern agriculture, becoming the most commercially successful and widely used herbicide of all time as of 2016. Despite a primary mechanism that targets a pathway absent from animal cells and regulatory studies showing safety margins orders of magnitude better than many other, more directly toxic herbicides, the safety status of glyphosate has recently been brought into question by a slow accumulation of studies suggesting more subtle health risks, especially when considered in combination with the surfactants it is usually applied with. Current, official views of respected international regulatory and health bodies remain divided on glyphosate’s status as a human carcinogen, but the 2015 International Agency for Research on Cancer decision to reclassify the compound as Category 2A (probably carcinogenic to humans) marked a sea change in the scientific community’s consensus view. The goal of this review is to consider the state of science regarding glyphosate’s potential as a human carcinogen and genotoxin, with particular focus on studies suggesting mechanisms that would go largely undetected in traditional toxicology studies, such as microbiome disruption and endocrine mimicry at very low concentrations. FULL TEXT