In Reply Ms Banach suggests that improvements in diagnosis and treatment over the past 30 years might explain a stable thyroid cancer mortality rate in the face of skyrocketing incidence. We1 agree that this is “possible,” but it is not plausible. To produce stable mortality, these improvements would have had to exactly match the change in incidence rate. If the improvements occurred too fast, mortality would fall; if the improvements occurred too slowly, mortality would rise. The most parsimonious explanation is that the vast reservoir of subclinical cancer is increasingly being detected, and this newly diagnosed disease is not destined to cause death.
Louise Davies, H. Gilbert Welch. Davies and Welch Draw Unfounded Conclusions about Thyroid Cancer from Epidemiological Data—Reply. JAMA Otolaryngol Head Neck Surg. 2014;140(7):679. doi:10.1001/jamaoto.2014.948