Ethical challenges of the linear non-threshold (LNT) cancer risk assessment revolution: History, insights, and lessons to be learned

Abstract

This paper provides historical review and evaluation of the development, adoption, and advocacy of the linear non-threshold (LNT) dose response model for cancer risk assessment as applied in practices and policies worldwide. It extends previous historical assessments and provides novel insights regarding: 1) how LNT bias became institutionalized in US governmental agencies, 2) how improper editorial practices at the journal Science promoted the adoption of LNT, 3) how a Nobel Prize winning scientist unjustifiably espoused and influenced support for replacing the threshold dose response model with the LNT model, 4) how the cover-up of striking and substantial experimental cancer data by US government scientists reduced support for the threshold dose response model at a critical period of cancer risk assessment policy adoption, and 5) how these events have negatively influenced cancer risk assessment practices and environmental and public health decisions for decades. These findings are presented to illustrate how profound and recognized mistakes, biases and unethical activities, inclusive of frank scientific misconduct, converged, and should motivate regulatory agencies worldwide to critically evaluate any existing policies that apply the LNT model as well as to serve as object lessons for current and future ethical conduct of research, and the provision of ethico-legal education in and across scientific curricula and institutions.