Making Use of Cancer Risk Assessment

By Omenn, Gilbert S. | Issues in Science and Technology, Summer 1996 | Go to article overview

Making Use of Cancer Risk Assessment


Omenn, Gilbert S., Issues in Science and Technology


To be effective, EPA's proposed new guidelines must be integrated into a comprehensive framework for risk management.

Risk is the coin of the realm in environmental, health, and safety regulation, and the nation is currently caught up in a heated debate about the uses and limitations of risk assessment and the benefits and costs of risk-reduction options. The Environmental Protection Agency's (EPA) proposed new guidelines for risk, as summarized in the accompanying article by Huggett and Wiltse, take an important step in the right direction by moving to incorporate emerging scientific advances. I point out some areas in which the guidelines can be improved, but the more important consideration is how to use them to improve risk management.

The first EPA guidelines, issued in 1976, were updated in 1986, largely in response to the 1983 National Research Council (NRC) report Risk Assessment in the Federal Government: Managing the Process (popularly known as the Red Book). The current proposal incorporates many of the recommendations of the 1994 NRC report Science and Judgment in Risk Assessment. The Red Book as well as the preceding work of the Interagency Regulatory Liaison Group and the Office of Science and Technology Policy in the Carter administration sought to stimulate development of more scientific evidence about chemical mechanisms and exposure patterns and individual variation in susceptibility. It was hoped that standard default assumptions and conversion factors would be overridden by chemical-specific data and new knowledge about rodent/human similarities and differences. It has been a slow process, both in eliciting data sets with sufficiently firm conclusions and in changing regulatory agency risk assessments.

Scientists in the many fields on which risk assessments draw are confident that understanding modes of action, variation in metabolism, pathways of exposure, effects of genes and nutrition, and new testing strategies, such as use of transgenic mice, will substantially enhance our ability to evaluate the carcinogenicity of chemicals. The proposed guidelines would use such information in an attempt to override routine extrapolations to the extent justifiable, thus strengthening the science base for regulation. To help users understand the risk assessments, EPA is requiring that each assessment be presented as a two-page narrative that sums up the supporting science rather than as a simple classification.

The plan to provide detailed characterizations of the evidence at each step in the risk assessment is wise. The differentiation of the dose-response relationship into what is observable and what is an extrapolation is also laudable. We must find ways to help all interested persons realize that the scientific method of observation and experimentation is at play in the observable range, which means studies in which there is at least 10 percent incidence of cancers, birth defects, or other adverse consequences. This rate of incidence is necessary to detect a statistically significant increase in incidence in comparison with that in unexposed groups of people or animals. In contrast, the extrapolation to upper-bound, lifetime risk estimates of 1 in 100,000 or 1 in 1,000,000 persons goes far outside the observable range and rests on scientific inference, assumptions, models, and speculation. Even in occupational settings, where lifetime risk estimates from chronic exposures may be on the order of 1 in 1,000, the small number of workers actually exposed to particular chemicals and the limited periods of exposure and follow-up put heavy burdens on inferences used in the epidemiologic methods.

Risky categories

One of the more controversial aspects of the proposed guidelines will be the definition of the three risk categories into which all substances will be grouped. Despite EPA's emphasis on the need for narratives to adequately communicate the nature of risk and to reflect the strength of the scientific evidence, it is inevitable that users of the information, ranging from California officials who implement the Proposition 65 program that requires warning labels on all potentially carcinogenic products to program officers in EPA itself, will continue to compile simple lists of carcinogenic chemicals from these characterizations. …

The rest of this article is only available to active members of Questia

Sign up now for a free, 1-day trial and receive full access to:

  • Questia's entire collection
  • Automatic bibliography creation
  • More helpful research tools like notes, citations, and highlights
  • Ad-free environment

Already a member? Log in now.

Notes for this article

Add a new note
If you are trying to select text to create highlights or citations, remember that you must now click or tap on the first word, and then click or tap on the last word.
One moment ...
Default project is now your active project.
Project items

Items saved from this article

This article has been saved
Highlights (0)
Some of your highlights are legacy items.

Highlights saved before July 30, 2012 will not be displayed on their respective source pages.

You can easily re-create the highlights by opening the book page or article, selecting the text, and clicking “Highlight.”

Citations (0)
Some of your citations are legacy items.

Any citation created before July 30, 2012 will labeled as a “Cited page.” New citations will be saved as cited passages, pages or articles.

We also added the ability to view new citations from your projects or the book or article where you created them.

Notes (0)
Bookmarks (0)

You have no saved items from this article

Project items include:
  • Saved book/article
  • Highlights
  • Quotes/citations
  • Notes
  • Bookmarks
Notes
Cite this article

Cited article

Style
Citations are available only to our active members.
Sign up now to cite pages or passages in MLA, APA and Chicago citation styles.

(Einhorn, 1992, p. 25)

(Einhorn 25)

1

1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

Cited article

Making Use of Cancer Risk Assessment
Settings

Settings

Typeface
Text size Smaller Larger Reset View mode
Search within

Search within this article

Look up

Look up a word

  • Dictionary
  • Thesaurus
Please submit a word or phrase above.
Print this page

Print this page

Why can't I print more than one page at a time?

Full screen

matching results for page

Cited passage

Style
Citations are available only to our active members.
Sign up now to cite pages or passages in MLA, APA and Chicago citation styles.

"Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn, 1992, p. 25).

"Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn 25)

"Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences."1

1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

Cited passage

Welcome to the new Questia Reader

The Questia Reader has been updated to provide you with an even better online reading experience.  It is now 100% Responsive, which means you can read our books and articles on any sized device you wish.  All of your favorite tools like notes, highlights, and citations are still here, but the way you select text has been updated to be easier to use, especially on touchscreen devices.  Here's how:

1. Click or tap the first word you want to select.
2. Click or tap the last word you want to select.

OK, got it!

Thanks for trying Questia!

Please continue trying out our research tools, but please note, full functionality is available only to our active members.

Your work will be lost once you leave this Web page.

For full access in an ad-free environment, sign up now for a FREE, 1-day trial.

Already a member? Log in now.