Toxics
Environmental Cancer Risk Scenarios for Lebanon: Quantitative Sensitivity Analysis and a Qualitative Genetic Susceptibility Framework
By Tamraz M, Nasr R and Temraz S.
Abstract
Background
Environmental exposures and biological susceptibility contribute to the complexity in cancer vulnerability, particularly in settings where comprehensive environmental monitoring and longitudinal exposure data are limited. Scenario-based modeling can provide a structured approach for exploring potential environmental cancer risks under uncertainty and identifying priorities for future research and surveillance.
Methods
We developed a scenario-based environmental cancer risk framework for Lebanon incorporating three exposure domains-perchlorate contamination, nitrate/nitrite exposure, and conflict-derived environmental contamination- and a qualitative Genetic Susceptibility Index (GSI). Monte Carlo simulations with 100,000 iterations were used to propagate uncertainty in literature-derived epidemiological effect estimates for colorectal and lung cancers under alternative hypothetical scaling assumptions. The GSI was used to organize qualitative susceptibility pathways but was not incorporated as a numerical modifier in the simulations. Thyroid cancer was evaluated separately through an illustrative hypothetical sensitivity analysis using author-defined relative-effect ranges because direct epidemiological estimates linking perchlorate exposure to thyroid cancer incidence were unavailable.