Editing DDT (section)

=== Carcinogenicity ===
In 2015, the [[International Agency for Research on Cancer]] classified DDT as Group 2A "probably carcinogenic to humans".<ref>{{Cite web|url=http://www.iarc.fr/en/media-centre/pr/2015/pdfs/pr236_E.pdf|title=IARC Monographs evaluate DDT, lindane, and 2,4-D|access-date=August 13, 2015|archive-date=April 13, 2020|archive-url=https://web.archive.org/web/20200413043943/http://www.iarc.fr/en/media-centre/pr/2015/pdfs/pr236_E.pdf|url-status=live}}</ref> Previous assessments by the U.S. [[National Toxicology Program]] classified it as "reasonably anticipated to be a carcinogen" and by the EPA classified DDT, DDE and DDD as class B2 "probable" [[carcinogen]]s; these evaluations were based mainly on animal studies.<ref name="ATSDRc5"/><ref name=Rogan05/> <!--In 2002, the [[Centers for Disease Control and Prevention]] reported, "Overall, in spite of some positive associations for some cancers within certain subgroups of people, there is no clear evidence that exposure to DDT/DDE causes cancer in humans."<ref name="ATSDRc5"/> -->

A 2005 Lancet review stated that occupational DDT exposure was associated with increased [[pancreatic cancer]] risk in 2 case control studies, but another study showed no DDE dose-effect association. Results regarding a possible association with [[liver cancer]] and biliary tract cancer are conflicting: workers who did not have direct occupational DDT contact showed increased risk. White men had an increased risk, but not white women or black men. Results about an association with multiple myeloma, prostate and testicular cancer, endometrial cancer and colorectal cancer have been inconclusive or generally do not support an association.<ref name=Rogan05/> A 2017 review of liver cancer studies concluded that "organochlorine pesticides, including DDT, may increase [[hepatocellular carcinoma]] risk".<ref>{{cite journal | vauthors = VoPham T, Bertrand KA, Hart JE, Laden F, Brooks MM, Yuan JM, Talbott EO, Ruddell D, Chang CH, Weissfeld JL | title = Pesticide exposure and liver cancer: a review | journal = Cancer Causes & Control | volume = 28 | issue = 3 | pages = 177–190 | date = March 2017 | pmid = 28194594 | pmc = 5336347 | doi = 10.1007/s10552-017-0854-6 }}</ref>

A 2009 review, whose co-authors included persons engaged in DDT-related litigation, reached broadly similar conclusions, with an equivocal association with testicular cancer. [[Case–control studies]] did not support an association with leukemia or lymphoma.<ref name="PineRiver"/>

====Breast cancer====
The question of whether DDT or DDE are [[Risk factors for breast cancer|risk factors in breast cancer]] has not been conclusively answered. Several meta analyses of observational studies have concluded that there is no overall relationship between DDT exposure and breast cancer risk.<ref>{{cite journal | vauthors = Park JH, Cha ES, Ko Y, Hwang MS, Hong JH, Lee WJ | title = Exposure to Dichlorodiphenyltrichloroethane and the Risk of Breast Cancer: A Systematic Review and Meta-analysis | journal = Osong Public Health and Research Perspectives | volume = 5 | issue = 2 | pages = 77–84 | date = April 2014 | pmid = 24955316 | pmc = 4064641 | doi = 10.1016/j.phrp.2014.02.001 }}</ref><ref>{{cite journal | vauthors = Ingber SZ, Buser MC, Pohl HR, Abadin HG, Murray HE, Scinicariello F | title = DDT/DDE and breast cancer: a meta-analysis | journal = [[Regulatory Toxicology and Pharmacology]] | volume = 67 | issue = 3 | pages = 421–433 | date = December 2013 | pmid = 24021539 | doi = 10.1016/j.yrtph.2013.08.021 | doi-access = free | pmc = 11298241 }}</ref> The United States Institute of Medicine reviewed data on the association of breast cancer with DDT exposure in 2012 and concluded that a causative relationship could neither be proven nor disproven.<ref>{{cite journal | vauthors = Smith-Bindman R | title = Environmental causes of breast cancer and radiation from medical imaging: findings from the Institute of Medicine report | journal = Archives of Internal Medicine | volume = 172 | issue = 13 | pages = 1023–1027 | date = July 2012 | pmid = 22688684 | pmc = 3936791 | doi = 10.1001/archinternmed.2012.2329 }}</ref>

A 2007 case-control study<ref name="Cohn07"/> using archived blood samples found that breast cancer risk was increased 5-fold among women who were born prior to 1931 and who had high serum DDT levels in 1963. Reasoning that DDT use became widespread in 1945 and peaked around 1950, they concluded that the ages of 14–20 were a critical period in which DDT exposure leads to increased risk. This study, which suggests a connection between DDT exposure and breast cancer that would not be picked up by most studies, has received variable commentary in third-party reviews. One review suggested that "previous studies that measured exposure in older women may have missed the critical period".<ref name="PineRiver"/><ref>{{cite journal | vauthors = Clapp RW, Jacobs MM, Loechler EL | title = Environmental and occupational causes of cancer: new evidence 2005–2007 | journal = Reviews on Environmental Health | volume = 23 | issue = 1 | pages = 1–37 | year = 2008 | pmid = 18557596 | pmc = 2791455 | doi = 10.1515/REVEH.2008.23.1.1 | bibcode = 2008RvEH...23....1C }}</ref> The National Toxicology Program notes that while the majority of studies have not found a relationship between DDT exposure and breast cancer that positive associations have been seen in a "few studies among women with higher levels of exposure and among certain subgroups of women".<ref name=NTP-DDT/>

A 2015 case control study identified a link (odds ratio 3.4) between ''in-utero'' exposure (as estimated from archived maternal blood samples) and [[breast cancer]] diagnosis in daughters. The findings "support classification of DDT as an endocrine disruptor, a predictor of breast cancer, and a marker of high risk".<ref>{{cite journal | vauthors = Cohn BA, La Merrill M, Krigbaum NY, Yeh G, Park JS, Zimmermann L, Cirillo PM | title = DDT Exposure in Utero and Breast Cancer | journal = The Journal of Clinical Endocrinology and Metabolism | volume = 100 | issue = 8 | pages = 2865–2872 | date = August 2015 | pmid = 26079774 | pmc = 4524999 | doi = 10.1210/jc.2015-1841 }}</ref>