Papanicolaou smear screening and cervical cancer. What can you expect?
B. Stenkvist, R. Bergstrom, G. Eklund and C. H. Fox
More than 90% of the total female population of three Swedish counties
between the ages of 30 and 59 years, 53% of women between 60 and 69 years,
and 25% of women older than 70 years were screened for cervical cancer with
the Papanicolaou smear over a ten-year period. The uniqueness of the study
is that in Sweden it is possible to follow up the entire population during
their lifetimes via a population register, which has its roots in the 17th
century, natural to Swedes but almost incomprehensible in the United States
or United Kingdom. Every Papanicolaou smear taken was computer recorded and
linked on an individual level to the cancer registry. There were 207,455
women followed up for ten years. No women were lost to follow-up. There was
a 75% decrease in invasive cervical cancer incidence among women who had
smears taken at least once during the ten-year period. Among those women
who had never had smears taken, the incidence of invasive cervical cancer
was four times as great as among those women who had been examined at least
once. We estimate that the system proposed by Swedish Medical Board (at
least one smear every three years) for cervical cancer screening can reduce
the incidence of invasive cervical cancer to a level between one and five
cases per 100,000 women per year in a completely screened population.
