Effect of population screening for cancer of the uterine cervix in Nijmegen, The Netherlands.

Since the introduction of a population screening program for cervical cancer in 1976, more than 85% of the female population between the ages of 35 and 54 years in the region of the city of Nijmegen, The Netherlands, has been screened. At first screening, severe epithelial abnormalities were diagnosed in 4.4 per 1,000 women, at second screening, in 1.5 per 1,000; and at third screening, in 1.0 per 1,000. The population screening program led to a marked increase in the detected number of carcinomata in situ. The number of cases of squamous cell cancer diagnosed in the first screening period did not increase. Once the population was screened, the detection rate of invasive squamous cell cancer in the group of women ages 35 through 54 decreased from 18.6 per 10(5) during the period prior to the screening to 9.0 per 10(5) after the first screening and 3.3 per 10(5) after the second screening. For the women above age 54, the incidence of invasive cancer was reduced by 58% after the second screening. The number of invasive cancers diagnosed in women under age 35 remained relatively small in spite of the large number of cases of carcinoma in situ.