Effect of a mass screening program on the risk of cervical cancer.

In Finland, the organized mass screening program for cervical cancer was initiated in the mid-1960s. In the early 1970s, the program became nationwide and it covered the age groups of 30 to 55 years. Currently, the screened age groups are 25 to 60 years, and the screening interval is 5 years. The organized program has resulted in a substantial decrease in the incidence of and mortality from cervical cancer. The reduction in age-specific incidence for all age groups from 30-34 to 50-54 years between the 1960s and 1980s was over 70%. At the age of 60 years and over there has been a slight decrease since the mid-1970s. The trends in mortality from cervical cancer have decreased correspondingly. Between the 1960s and 1980s, the reduction in age-specific mortality for age groups from 30-34 to 54-59 years was about 80%. The decrease was about 50% in the age group 60 to 69 years. At the age of 70 years and over, the decrease was smaller.