Increased awareness and improved diagnostic techniques have led to earlier diagnosis of prostate cancer and increased detection of subclinical cases, resulting in improved prognosis. We postulated that the considerable increase in incidence under age 60 is not attributable only to increased detection. To test this hypothesis, we studied incidence, mortality and relative survival among middle-aged patients diagnosed in south-east Netherlands and East Anglia (UK) between 1971 and 1994. Prostate-specific antigen (PSA) testing did not occur before 1990. Between 1971 and 1989, the age-standardized incidence at ages 40-59 increased from 8.8 to 12.5 per 10(5) in The Netherlands and from 7.0 to 11.6 per 10(5) in East Anglia. Five-year relative survival did not improve in East Anglia and even declined in southeast Netherlands from 65% [95% confidence interval (CI) 47-83) in 1975-79 to 48% (CI 34-62) in 1985-89. Mortality due to prostate cancer among men aged 45-64 years increased by 50% in south-east Netherlands and by 61% in East Anglia between 1971 and 1989, but decreased slightly in the 1990s. Because other factors adversely influencing the prognosis are unlikely, our results indicate an increase in the incidence of fatal prostate cancer among younger men in the era preceding PSA testing.