HPSM Lecture - Anya Plutynski, Washington University in St. Louis

Title: Is Cancer Due to Bad Luck?

Abstract: In 2015, Tomasetti and Vogelstein published a paper in Science containing the following provocative statement:

… only a third of the variation in cancer risk among tissues is attributable to environmental factors or inherited predispositions. The majority is due to “bad luck,” that is, random mutations arising during DNA replication in normal, noncancerous stem cells.

The paper – and perhaps especially this rather coy reference to “bad luck” – became a flash point for a series of letters and reviews, followed by replies and yet further counterpoints. The aim of this talk is first, to briefly explain and describe Tomasetti and Vogelstein's argument and conclusions. I then turn to a discussion of why this statement was so controversial, both among scientists and public health advocates. Last but not least, I discuss why and what sense cancer is a matter of "luck," or, better: probabilistic causal processes. The questions raised by critics of Tomasetti and Vogelstein concern not only whether as number and rate of stem cell division in different tissue types account for average differences in incidence, but whether such statistical correlations are sufficient to explain these patterns. The case thus serves as an interesting case study in the role of idealized models in scientific explanation, as well as what it means (or ought to mean) to explain population level patterns of the sort described by epidemiologists. I conclude by considering some implications of the debate for both primary and secondary prevention.