Biases, Fear and Thyroid Cancer

In the NYTimes’ "Consults" today an endocrinologist answers questions about whether thyroid cancer has to do with toxins or genes. The first question from "Toxins, Genes and Thyroid Cancer" inquires as to whether a cancer "cluster" in an office could be due to environmental (i.e. man-made) toxins. The endocrinologist correctly responds that the incidence of thyroid cancer has increased dramatically over the last two decades. He goes on though to hedge that "no specific chemical or environmental factor has been demonstrated to commonly cause thyroid cancer in humans." With regard to whether the illness is hereditary he takes a firmer position stating that most forms of the cancer are not considered to be so. Only three wrote in to comment. They wondered whether too much iodine, "hundreds of chemicals in our bloodstream" or flame retardants and the linings of cat food tins might be to blame.

If you defend toxic tort litigation or have ever tried to explain the sudden rise and then plateau in rates of breast or prostate cancer you know it’s time to pause and beat your head on the desk for a bit.

Feel better? Now for something to fit with the other puzzle pieces. Read: "Increasing World Incidence of Thyroid Cancer: Increased Detection or Higher Radiation Exposure?" As the authors make clear, improved detection and screening may well be, but has not quite yet been confirmed to be, the answer. In any event the evidence for better detection is a whole lot stronger than for cat food tins and copy machines.