Cancer Risk Assessment with Intermittent Exposure

Applications of methods for carcinogenic risk assessment often focus one estimating lifetime cancer risk. With intermittent or time-dependent exposures, lifetime risk is often approximated on the basis of a lifetime average daily dose (LADD). In this article, we show that there exists a lifetime equ...

Full description

Saved in:
Bibliographic Details
Main Authors: Murdoch, Duncan J, Krewski, Daniel, Wargo, John
Format: Report
Language:English
Subjects:
CANCER
Component Reports
Medicine and Medical Research
ONCOGENESIS
RISK
Stress Physiology
Online Access:Request full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Applications of methods for carcinogenic risk assessment often focus one estimating lifetime cancer risk. With intermittent or time-dependent exposures, lifetime risk is often approximated on the basis of a lifetime average daily dose (LADD). In this article, we show that there exists a lifetime equivalent constant dose (LECD) which leads to the same lifetime risk as the actual time-dependent exposure pattern. The ratio C = LECD/LADD then provides a measure of accuracy of risk estimates based on the LADD and a basis for correcting such estimates. Theoretical results derived under the classical multistage model and the two-stage birth-death-mutation model suggest that maximum value of C, which represents the factors by which the LADD may lead to underestimates of risk, will often lie in the range of two to five fold. The practical application of these results is illustrated in the case of astronauts subjected to relatively short-term exposure to volatile organics in a closed space station environment and in the case of the ingestion of pesticide residues in food where consumption patterns vary with age This article is from 'Proceedings of The Conference on Chemical Risk Assessment in the DoD: Science, Policy and Practice, Held in Dayton, OH on April 8 - 11, 1991. AD-A268 643, p119 - 129.