A UCLA study recently linked increased physical activity at work with a decreased chance of developing prostate cancer. In addition, it linked exposure to TCE (amongst a handful of other chemicals) with increased rates of prostate cancer. According to UCLA's Johnson Cancer Center:

Researchers studied more than 2,100 men who worked at the Rocketdyne facility in the San Fernando Valley, many of whom were exposed to radiation and chemicals that may have increased their risk for certain cancers. The research team identified 362 men who developed prostate cancer and compared them to 1,805 men of similar age and socioeconomic status who did not get prostate cancer.

The study, done in conjunction with researchers at the Olive View-UCLA Education and Research Institute and the University of Michigan, appears in the February issue of the journal Cancer Causes Control.

"The message from this study for today is that if you're more active, you may be able to prevent this cancer from happening," said Beate Ritz, a Jonsson Cancer Center researcher, an associate professor of epidemiology in the UCLA School of Public Health and the study's senior author. "If you have a desk job, do something physically active to counterbalance it."

[...]

The study found that the men who developed prostate cancer were less likely to hold the more physically active jobs. Those that got cancer also were more likely than the control group to be highly exposed to the chemicals that were evaluated, including hydrazine, benzene, mineral oil, polycyclic aromatic hydrocarbons (PAHs) and trichloroethylene (TCE), which are known or suspected carcinogens.

Though the focus on physical activity appears to be the main thrust of this research, we think the TCE-related finding is worth highlighting.

Read the news about the study here. For the study itself ("Nested case–control study of occupational physical activity and prostate cancer among workers using a job exposure matrix"), see here.

When this blog first launched, we created a topic category called "Health Effects". This was one of many topic categories we included to enable readers to find pertinent information more easily (see the list of "Topics" to the left).

Over time, we have realized that many of our readers have a particular interest in the way TCE (or related solvents) impacts specific organs in the body — and what is known about its relationship to particular diseases. As such, we've decided to begin categorizing health effects information (articles, studies, resources, etc) by target site/organ in the body. In doing so, we've created a number of new Health Effects categories. In a few cases, we've created specific disease categories, such as Lymphomas or Leukemia.

Want to know how TCE effects the brain? Click on Health Effects - Brain. The heart? Click on Health Effects - Heart. Want to to see all posts related to all health effects? Choose Health Effects - All.

At the moment, you'll notice these categories are relatively empty. It may take us a few days or more to re-categorize all of our old health effects-related posts. In addition, as we publish new items related to specific health effects in the future, you will be able to find them in these new categories. Over time, we hope to add as many resources as possible in each category so that the TCE Blog continues to be a useful online resource.

Note: If there are resources (or categories) you would like to see added to our library of health effects information, please don't hesitate to contact us. Also, please don't hesitate to shout if you think there is a better/easier way to organize this information.

This article was made available online yesterday by Environmental Health Perspectives. From the abstract [PDF]:

Trichloroethylene Monograph
Trichloroethylene Cancer Epidemiology: A Consideration of Select Issues
Cheryl Siegel Scott and Weihsueh A. Chiu

A large body of epidemiologic evidence exists for exploring causal associations between cancer and trichloroethylene (TCE) exposure. The U.S. Environmental Protection Agency’s 2001 draft TCE health risk assessment concluded that epidemiologic studies, on the whole, support associations between TCE exposure and excess risk of kidney cancer, liver cancer, and lymphomas, and, to a lesser extent, cervical cancer and prostate cancer. As part of a minimonograph on key issues in the health risk assessment of TCE, this article reviews recently published scientific literature examining cancer and TCE exposure and identifies four issues that are key to interpreting the larger body of epidemiologic evidence: (1) relative sensitivity of cancer incidence and mortality data; (2) different classifications of lymphomas, including non-Hodgkin’s lymphoma; (3) differences in data and methods for assigning TCE exposure status; and (4) different methods employed for causal inferences, including statistical or meta-analysis approaches. The recent epidemiologic studies substantially expand the epidemiologic database, with seven new studies available on kidney cancer and somewhat fewer studies available that examine possible associations at other sites. Overall, recently published studies appear to provide further support for the kidney, liver, and lymphatic systems as targets of TCE toxicity, suggesting, as do previous studies, modestly elevated (typically 1.5 to 2.0) site-specific relative risks, given exposure conditions in these studies. However, there are a number of challenging issues that need to be considered before drawing causal conclusions about TCE exposure and cancer from these data.

Download the full version here [PDF]

The International Agency for Research on Cancer classifies Trichloroethylene (TCE) as probably carcinogenic to humans (Group 2A). Here's a direct link to IARC's summary and evaluation (Updated 1997).



Update: The direct link above is no longer active. Try here.

Direct link here. Also added as permanent link in the right column under Science/Agency sites (------>)

Update:

ATSDR's full Toxicological profile of TCE (1997) is here.

Since approximately 1993, the ATSDR has been tracking the health effects reported by discreet communities exposed to Trichloroethylene. Their National Exposure Registry (NER) basically tracks this kind of data for well-identified communities who have been exposed to it (there are myriad qualification requirements, I'm simplifying here).

The NER for TCE has some interesting data and discussion. It raises questions about elevated cancer findings among the TCE-exposed population. Unfortunately, the detailed comparison of cancer types by age/sex for the exposed population vs. the general population never actually appears in the reports (despite references to appendices with this data in 3 separate reporting years: 1994, 1996, and 1999). Maybe I just can't find it. To be sure, in May of 2004, I wrote the ATSDR to request the missing data/appendices. I received this response:

Mr. Fischbein:

The TCE Subregistry cancer outcomes analyses are slated to be released under a separate study. The results are not publically available at this time. Please do keep tabs on our publications for future releases.

I confess, I'm not sure what to make of this. If anybody has any thoughts, please let me know or feel free to use the comments feature below.

In 2002, the EPA's Science Advisory Board (SAB) reviewed the EPA's 2001 draft health assessment of TCE. The SAB "commends the [EPA] for its groundbreaking work [...] in several important new areas of risk assessment" while also providing suggestions "to strengthen and provide confidence in the assessment."

Here is the full SAB review. Thanks to reader VJ for the link.

Here's a direct link to the EPA's 2001 Document: Trichloroethylene Health Risk Assessment: Synthesis and Characterization (external review draft)

From the EPA's abstract:

This assessment presents EPA's most current evaluation of the potential health risks from exposure to trichloroethylene (TCE). TCE exposure is associated with several adverse health effects, including neurotoxicity, immunotoxicity, developmental toxicity, liver toxicity, kidney toxicity, endocrine effects, and several forms of cancer. Mechanistic research indicates that TCE-induced carcinogenesis is complex, involving multiple carcinogenic metabolites acting through multiple modes of action. Under EPA's proposed (1996, 1999) cancer guidelines, TCE can be characterized as "highly likely to produce cancer in humans."

Update:

I'm trying to find the published responses to this document. I know the Halogenated Solvents Industry (along with several others, if I recall correctly) filed a rather lengthy response. If anyone knows where I can find these, please email me.