Screening for breast cancer in Nijmegen. Report of 6 screening rounds, 1975-1986.
A population-based screening programme for breast cancer was initiated in Nijmegen in 1975 with mammography as the only screening procedure. Up to January 1987, 6 screening rounds were carried out with a 2-year screening interval. Rates of attendance, referral, biopsy and detection were calculated and numbers of interval cancers are presented in order to give a clear view of what repeated screening can accomplish in a population. At the first screening round the attendance rate was 87% for women under age 50 and 83% for women aged 50-64. For women aged 65 or over the initial attendance rate was 40%. Rates of attendance declined in subsequent years. Detection rates were highest for elderly women at their first examination: 9.5 per 1,000 screened women. Corresponding rates were 5.6 and 2.3 per 1,000 for women aged 50-64 and below 50 respectively. The positive predictive value for referral was, on average, 20% for women under age 50 and 50% for elderly women, although a sharp increase was seen in the last 2 screening examinations for all age-groups. Predictive values for biopsy were higher: 30% on average for women aged under 50 and 60%-70% for elderly women, again with a sharp increase in the last 2 screening rounds. Interval cancer rates, calculated as the number of cancers occurring within 2 years among negatively screened women at risk, showed no particular trend and varied between 0.9-1.3 per 1,000 woman-years after each screening round. Compared to screen-detected cancers, interval cancers occurred more frequently in younger women. In women under age 50, the ratio between screen-detected and interval cancer was about 1:1, while it was about 2:1 for elderly women.
Peeters
P H
PH
Department of Epidemiology, St. Radboud Hospital, Nijmegen University, The Netherlands.
Verbeek
A L
AL
Hendriks
J H
JH
van Bon
M J
MJ
D000328:Adult; D000367:Age Factors; D000368:Aged; D001706:Biopsy; D001940:Breast / Q000473:pathology; D001943:Breast Neoplasms / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000473:pathology / Q000517:prevention & control; D005260:Female; D006801:Humans; D008327:Mammography; D008403:Mass Screening; D008875:Middle Aged; D009426:Netherlands; D010349:Patient Compliance; D011237:Predictive Value of Tests; D012017:Referral and Consultation