Letter to the Editor: Cancer rates not explained by smoking: how to investigate a single county

We recently published “Cancer rates not explained by smoking: a county-level analysis” in your journal [1]. Using U.S. Surveillance, Epidemiology and End Results (SEER) cancer incidence and population data for 612 counties [2], we simulated the expected effect of eliminating smoking on the rates of 12 types of cancer known to be caused by smoking [3]. We estimated that in 2016, 39.8 % of the cancer incidence of these 12 types would not have occurred had smoking been eliminated. Conversely, about 60 % of these cancers would still occur, even in the absence of smoking. This finding is in good agreement with previously published estimates of the “attributable fraction” of cancer due to smoking [4].