Oral contraceptives containing chlormadinone acetate and cancer incidence at selected sites in the German Democratic Republic--a correlation analysis.

The use of oral contraceptives containing chlormadinone acetate in 1972 by women of 13 districts (out of 15) of the GDR has been related to the incidence of cancer of breast, corpus uteri, and ovary during the period 1961 to 1980. Cancer incidence was represented by cohort parameters showing the risk of the cohorts in relation to each other. No statistically significant association between the two events was noted. Although not significant, our data are consistent with an elevated relative risk for breast cancer of 1.3 and a decreased risk for ovarian cancer of 0.5.