Re: Evaluating Gastric Cancer Misclassification: a Potential Explanation for the Rise in Cardia Cancer Incidence

Increased incidence of adenocarcinoma of the gastric cardia has been reported over the last few decades from several areas of North America and Europe (1–2). A mortality study from the Swedish Cancer Registry, however, suggested that the observed upward trends can be, partly or largely, accounted for by changed accuracy of registration within gastric subsites (3). We considered, therefore, trends in incidence rates for various gastric subsites in the Cancer Registry of the Swiss Canton of Vaud (covering approximately 600 000 inhabitants in 1990 from the French-speaking part of Switzerland) over the period from 1976 through 1997. In this area, uniform criteria of classification have been adopted, and traditional attention has been focused on careful endoscopic and histopathologic examination of gastric lesions (4–6). Table 1 gives average age-adjusted (on the world standard population) incidence rates for various subsites of gastric cancer during three separate calendar periods. In both sexes, no appreciable change in incidence of adenocarcinoma of the gastric cardia was observed (3.1 cases per 100 000 males, and 0.5 cases per 100 000 females from 1976 through 1979 versus 3.2 and 0.1, respectively, from 1995 through 1997), while appreciable downward trends were observed for distal and other or unspecified gastric cancer sites. These data, from a carefully surveyed European population, therefore do not support the existence of a systematic and major rise in incidence of cardiac adenocarcinomas (3,7), confirming that—in proportional terms—the cancers of the gastric cardia have become