Incidence registration and survival data from brain neoplasms have been analyzed from the population-based system of the Cancer Registry of the Swiss Canton of Vaud, which has been operating in a particularly favorable environment for surveillance and using an integrated and homogeneous system of cancer registration. Between 1974 and 1987, a total of 401 cases was registered, corresponding to an age-adjusted rate for all malignant histotypes of 5.3/100,000 (world standard) for the period 1975-1980 and 5.0 for 1981-1987 in males, and of 3.9 and 3.7, respectively, in females. Thus, no increase in brain neoplasm incidence has taken place in this population, and indeed some decline has been observed in males, particularly for gliomas (from 2.7 to 2.0). During the most recent calendar period, incidence rates were 2.0 in males and 1.5 in females for gliomas, 0.9 in both sexes for astrocytomas, 0.4 in males and 0.1 in females for oligodendrogliomas, and 1.7 in males and 1.2 in females for other or unspecified histotypes. For both gliomas, astrocytomas and total brain neoplasms, the peak rate was observed in the age group 55-74, and some flattening of rates was registered above age 75. Overall 5-year survival was 16%. While there was no difference between sexes, survival rates were substantially lower at older (greater than or equal to 60 years, 3%) than at younger (less than 60 years, 26%) age, and for gliomas (7% at 5 years) than for other histological types. However, the histotype distribution could not explain the major difference in survival by age, since similar differences were observed for various histotypes.(ABSTRACT TRUNCATED AT 250 WORDS)