Cancer risk assessment process

Several assays have been developed for assessing genetic alterations in germ cells. The information developed can be used for hazard identification in the cancer risk assessment process or, more appropriately, in the development of a genetic risk assessment. The decision of when to conduct a germ cell assay is an important one because the assays are generally expensive and time-consuming. An exception is the use of Drosophila in assays that can serve as a substitute for mammalian assays. 

Most scientists would hold that these unknowns and uncertainties in the regulatory risk-assessment model would tend to favor risk overestimation rather than underestimation or accurate prediction. While this view seems correct, it must be admitted that there is no epidemiological method available to test the hypothesis of an extra lifetime cancer risk of about 10 per 1000 000 from methylene chloride in drinking water. The same conclusion holds for most environmental carcinogens. It is also the case that more uncertainties attend the risk assessment process than we have indicated above. 

In some instances, the specific data on a given chemical or pollutant source will replace conservative defanlt options used in earlier assignments. The report includes two authored appendices that address issues related to the use of default options and their replacement by specific scientific information. One appendix (by Finkel) advocates a principle of plausible conservatism for choosing and altering default options and in making cancer risk estimates. The second appendix (by McClellan and North) advocates the full use of scientific information in the risk assessment process. 

Kimmel GL (1995) Exposure-duration relationships The risk assessment process for health effects other than cancer. Inhal Toxicol, 7 873-880. 

The concept of how data from genotoxicity assays can be used in both cancer and genetic risk assessments was introduced in Section 25.2. This concept is expanded here to provide a broader rationale for the collection of genotoxicity data in support of these risk assessment processes. 

Farland WH. Cancer risk assessment Evolution of the process. Prev Med... 

Food products contain thousands of compounds — some of nutritive value — nonnutritive components, numerous additives, substances formed during processing, and pesticide residues. Their safety is of utmost importance for human health protection, including cancer risk assessment. In order to evaluate the carcinogenicity of individual food constituents and their mixtures, often of unknown chemical structure, as well as the impact of cooking procedures, short-term reliable and inexpensive tests are necessary. Since cancer risk associated with chemical compounds is thought to stem mainly from their ability to induce mutations, mutagenicity... 

The purpose of these guidehnes was to outline a procedure that EPA scientists could use to assess the cancer risk associated with exposure to chemicals in the environment. This document was also used to inform the public about the process of cancer risk assessment. 

Judicial decisions in nonregulatory contexts such as toxic tort and product liability suits are likewise inconsistent in their consideration of the linear, no threshold model. As in the regulatory context, most cases find no problem with an expert s reliance on a risk assessment using the linear model. In a handful of cases, however, the court rejects reliance on a linear dose-response assumption. Eor example, one court in addressing the cancer risks from a low concentration of benzene in Perrier held that there is no scientific evidence that the linear no-safe threshold analysis is an acceptable scientific technique used by experts in determining causation in an individual instance (Sutera 1997). Another court decision concluded that [t]he linear non-threshold model cannot be falsified, nor can it be validated. To the extent that it has been subjected to peer review and publication, it has been rejected by the overwhelming majority of the scientific community. It has no known or potential rate of error. It is merely an hypothesis (Whiting 1995). The inconsistency and unpredictability of judicial review of risk assessments adds an additional element of uncertainty into the risk assessment process. 

Application of cancer risk assessment values in the context of soil contamination is conducted in the United States under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) of 1980, also known as the Superfund program. This law was enacted to address abandoned hazardous waste sites through development of a mechanism to provide funding and a process to rate the hazard of... 

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