[Breast cancer in the Estonian SSR: incidence and survival rate]

On the basis of statistical data including all the cases of breast cancer in females (2.250), registered in 1969-1976 in Estonia, the incidence and 5-year survival rates were studied. Comparing two periods 1969-1972 and 1973-1976, age-adjusted (world standard population) incidence rates were 24.8 +/- 0.8 and 27.3 +/- 0.8, respectively (P greater than 0.05) per 100,000. Truncated standardized incidence rates (age 35-64) were 60.0 +/- 2.3. and 67.1 +/- 2.4, respectively (R less than 0.05) and cumulative rates 2.74 and 2.96 (per cent), respectively. Thus, increasing time trends in breast cancer incidence can be mentioned. There was a statistically significant decrease of breast cancer incidence in the age group of 35-39 years (R less than 0.05). Out of 742 patients (registered in 1969-1971) 735 (99.0 +/- 0.4 per cent of all these cases) were followed up. The crude 5-year survival rate was 50.6 +/- 1.8%, or 53.4 +/- 1.9% when 38 patients known to have died from other causes but breast cancer were eliminated.