[Mortality trends caused by neoplasms of the digestive system. Soria, 1950-1985].

The deaths caused by tumours of the digestive system (oesophagus, stomach, colon-rectum, gallbladder and pancreas) recorded in the province of Soria between 1950 and 1985 have been analyzed according to risk and mortality rates. Standardized (adjusted) rates in relation to sex and site of residence (urban-rural) of the deceased were calculated for the decades 1950-1959, 1960-1969, 1970-1979 and the period between 1980 and 1985. Standard errors were calculated to establish confidence limits according to Miettinen's method. The data were obtained from the death certificates of the various registries of the Soria province, including name and surnames, sex, age and site of the tumour according to the 9th revision of the International Classification of Diseases. There is a significant decrease in the mortality risk for tumours of the stomach in both sexes (p less than 0.01) and in liver tumours in females (p less than 0.01). On the other hand, there is an increased risk in both sexes for pancreatic cancer (p less than 0.05 M, p less than 0.01 F) and for oesophageal tumours in men (p less than 0.05). Similarly, during 1980-1985 men were at a significantly greater risk of dying from oesophageal, gastric and liver cancer (p less than 0.01) as well as rectum and colon (p less than 0.05). As far as stomach tumours are concerned there are significant differences between rural and urban areas both in males (p less than 0.01) and in females (p less than 0.05).