PFAS and Cancer: Which Diseases Are Linked to Forever Chemical Exposure?

PFAS and Cancer: What the Research Shows

The link between PFAS exposure and cancer has been established through multiple lines of scientific evidence: occupational studies of workers at PFAS manufacturing facilities, community health studies of residents with PFAS-contaminated drinking water, and animal toxicology studies. The National Cancer Institute (NCI) recognizes kidney cancer and testicular cancer as having the strongest evidence linking them to PFAS exposure.^[1]

Much of the foundational epidemiological research on PFAS health effects comes from studies of communities near DuPont's Washington Works plant in Parkersburg, West Virginia. A landmark 2005 class action settlement between DuPont and affected community members created a Science Panel that conducted the most comprehensive community health study of PFOA exposure ever conducted. The C8 Science Panel examined health data for over 69,000 people and in 2012 found that PFOA exposure was more likely than not to cause six diseases: kidney cancer, testicular cancer, ulcerative colitis, thyroid disease, high cholesterol, and pregnancy-induced hypertension.^[2]

Scientific understanding of PFAS toxicity continues to evolve. While PFOA and PFOS are the most studied, newer replacement PFAS chemicals are raising new concerns. The 2024 EPA drinking water standards reflect the current scientific consensus, but research on PFAS health effects is an active and rapidly developing field.^[1]

Kidney Cancer and PFAS

Kidney cancer (renal cell carcinoma) is one of the two malignancies most strongly associated with PFAS exposure. NCI research and the C8 Science Panel both identified PFOA exposure as likely causal in the development of kidney cancer. PFAS accumulate in the kidneys as the body attempts to filter and excrete them, which may explain the organ's particular vulnerability.^[1]

The American Cancer Society estimates approximately 81,000 new kidney cancer cases will be diagnosed in the U.S. in 2024. Studies of workers at PFAS manufacturing facilities have found approximately two times the expected rate of kidney cancer. Community studies near contaminated water sources have also found elevated rates, particularly in populations with long-term high-level exposure.^[3]

PFOA was classified by IARC as a Group 2B carcinogen (possibly carcinogenic to humans) in 2017, primarily based on kidney cancer evidence. Ongoing review of PFAS as a class may result in reclassification to more concerning categories as new studies are completed.^[5]

Testicular Cancer and PFAS

Testicular cancer, while relatively rare, disproportionately affects young men and is the cancer with the strongest documented link to PFAS exposure in some studies. The C8 Science Panel found that PFOA exposure was more likely than not to cause testicular cancer among highly exposed community members.^[2]

Research on military personnel stationed at PFAS-contaminated bases has found significantly elevated testicular cancer rates compared to unexposed military populations. Studies of PFAS workers at 3M and DuPont facilities have similarly shown elevated testicular cancer incidence. The mechanism may involve PFAS disruption of androgen (testosterone) signaling.^[4]

Testicular cancer is notable in the context of PFAS litigation because it typically affects men in their 20s, 30s, and 40s, meaning that men exposed to PFAS during childhood or military service may develop this cancer decades later. Affected individuals include both military veterans and civilians from contaminated communities.^[2]

Thyroid Disease and Thyroid Cancer

PFAS are known endocrine disruptors, meaning they interfere with hormone signaling. The thyroid gland, which regulates metabolism and development through thyroid hormones, is particularly vulnerable. NIEHS research has documented associations between PFAS exposure and both hypothyroidism (underactive thyroid) and hyperthyroidism, as well as thyroid cancer.^[5]

PFAS appear to disrupt thyroid hormone transport and metabolism. Several large epidemiological studies have found that people with higher blood PFAS levels are more likely to have thyroid disease. A 2010 study in Environmental Health Perspectives found that adults with higher PFOS serum levels had significantly greater odds of thyroid disease.^[5]

Thyroid disease from PFAS exposure can have cascading health effects, as thyroid hormones regulate metabolism, heart rate, bone density, cholesterol levels, and numerous other physiological processes. Pregnant women with thyroid disruption from PFAS may also have children with developmental effects, as thyroid hormones are critical for fetal brain development.^[5]

Other PFAS-Linked Conditions

Beyond cancer, extensive research has linked PFAS exposure to a range of other serious health conditions:

• High cholesterol (hypercholesterolemia): One of the most consistently replicated PFAS health effects. Multiple studies across different PFAS-exposed populations have found that higher PFAS blood levels are associated with elevated LDL cholesterol and total cholesterol. High cholesterol increases cardiovascular disease risk.
• Ulcerative colitis: The C8 Science Panel found a more likely than not causal link between PFOA exposure and ulcerative colitis, a chronic inflammatory bowel disease. The mechanism may involve PFAS suppression of the gut immune response.
• Immune system dysfunction: Studies of children and adults have found that PFAS exposure reduces the immune response to vaccines, suggesting that PFAS may generally impair immune function. A 2020 National Academies report highlighted immune suppression as a key PFAS health concern.
• Pregnancy-induced hypertension and preeclampsia: Pregnant women with higher PFAS blood levels have elevated rates of pregnancy-induced hypertension and preeclampsia, which carry risks for both mother and child.
• Low birth weight and developmental effects: Prenatal PFAS exposure has been associated with lower birth weight, reduced gestational age, and potential effects on child development.
• Non-alcoholic fatty liver disease (NAFLD): PFAS accumulate in the liver and research has associated higher PFAS levels with elevated liver enzymes and NAFLD.

IARC and NCI Research on PFAS Cancer Risk

The International Agency for Research on Cancer (IARC), part of the World Health Organization, evaluates the carcinogenicity of substances through its Monographs program. PFOA has been evaluated and classified as a Group 2B carcinogen (possibly carcinogenic to humans). PFAS as a class are under ongoing evaluation, and reclassification to higher hazard categories is anticipated as the evidence base grows.^[5]

The National Cancer Institute conducts and funds research on environmental contributors to cancer, including PFAS. NCI's PFAS research page compiles current scientific findings and highlights kidney cancer and testicular cancer as the conditions with the most consistent evidence. NCI researchers are also investigating potential PFAS links to bladder cancer, prostate cancer, and non-Hodgkin lymphoma.^[1]

The scientific consensus on PFAS cancer risk has strengthened significantly over the past decade. What began as findings in occupational cohorts has been replicated in community-based studies and is now supported by sufficient evidence to underpin federal regulatory action, large-scale litigation, and substantial settlements.^[1]

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