LAUSR

Dear Editor The European Council of Vinyl Manufacturers (ECVM) wishes to comment on some aspects of the article by Cicalese et al. [1] in order to stress that the conclusions drawn by the authors are not properly substantiated. In particular, a link between increased risk of hepatocellular carcinoma (HCC) and vinyl chloride monomer (VCM) exposure is not demonstrated by the data cited in the study. Before listing our main comments, we also would like to draw your attention to some minor but disturbing inaccuracies in the article: • In the Abstract, hepatitis C and B are exchanged. • In the section Data on page 289, the terms HCC incidence and liver cancer incidence are incorrectly exchanged. Indeed, it is liver cancer incidence which is reported by the Texas Cancer Registry, not HCC rates. The authors used 4 sets of National Air Toxics Assessment (NATA) data for the years 1996, 1999, 2002, and 2005; these data were compared with HCC rates from 2000–2013 and 2006–2013. The median latency period for angiosarcoma of the liver and HCC is 36–48 years [2] rather than the duration of 7–13 years used in the study. The length of time between estimated VCM concentrations at county level and observation periods for HCC is, therefore, far too short. Comparing data from NATA 2005 with HCC observations in 2006– 2013 entails especially a time frame of 1–8 years, rendering the association totally irrelevant. The whole method regarding the data from the US Environmental Protection Agency (EPA) NATA, as presented on pages 290 and 291, is insufficiently described. As a consequence of this insufficient description, even though it is stated that “the analysis was conducted using data obtained from publicly available sources” [1], the reproducibility, replicability, and checking of the outcomes is hindered. The EPA NATA have actually described their methods extensively, and they are indeed publicly available, but what kind of data from the extensive NATA database are exactly used and how they are processed is unclear. Published online: April 11, 2018