Decreased incidences of intestinal and diffuse types of gastric carcinoma in Finland during a 20-year period.

The incidence of gastric carcinoma (GCA) has decreased throughout the world. This decrease is attributed to a decline in incidence of the intestinal type of GCA (IGCA), whereas the diffuse (DGCA) type of GCA is considered to be endemic in nature and more stable in incidence. In the present study we have estimated how much the incidences of IGCA and DGCA have decreased in percentage in Finland from 1952-61 to 1972-81. Our calculations are based on the Finnish Cancer Registry data of new GCA cases, on population statistics in Finland, and on the percentage distribution of GCA subtypes in three consecutive samples of GCA patients collected in the time periods 1952-61 (reference series) and 1972-81 (two separate samples: series A and B). The samples totaled 1837 GCA cases. We calculated that the incidence of IGCA had decreased from 1952-61 to 1972-81 by 62-71% (reference series versus series A - reference series versus series B) among men and by 69-70% among women. Correspondingly, the incidence of DGCA was calculated to have decreased by 30-39% among men and 37-42% among women. We conclude that not only has the incidence of IGCA decreased in percentage approximately twice as much as the incidence of DGCA but DGCA has also distinctly decreased in incidence in Finland from 1952-61 to 1972-81.