Cervical screening in women over the age of fifty: results of a population based multicentre study

OBJECTIVE: It has been suggested that women over 50 with a satisfactory negative smear history are at low risk for dyskaryosis and might be suitable for withdrawal from the cervical screening programme. The objectives of this study are to document the pattern of dyskaryosis in the cervical smears of women over 50 and to relate the risk of dyskaryosis in these women to the prior smear history.
DESIGN: Available computerised smear data were analysed.
SETTING: Five regions in England and Scotland; Aberdeen, Dundee, Birmingham, Gateshead and Nottingham.
POPULATION: All women aged 50 or over who had a satisfactory smear between 1988 and 1996.
METHODS: Smear results were sorted into individual smear records. The first smear after the age of 50 was identified as well as all smears before and after the age of 50.
MAIN OUTCOME MEASUREMENTS: The smear history before and after the age of 50 was determined for all women. The relative risk of dyskaryosis as well as the time to dyskaryosis was calculated for women whose raw data were available.
RESULTS: The study included 170,436 women with at least one satisfactory smear after 50. No results of previous smears were available in 90,546 (54%) of women but 36,512 (21%) of women had a satisfactory negative smear history. Women with prior dyskaryosis or borderline nuclear abnormalities (BNA) had an increased risk of dyskaryosis after the age of 50 compared with women with a negative history (RR 4.39 and 3.08 respectively). It was notable that 1.8% of women with a negative history still demonstrated subsequent dyskaryosis.
CONCLUSIONS: Women with either dyskaryosis or BNA before 50 are not suitable for withdrawal from cervical screening. Well-screened women with a negative smear history at the age 50 still have a residual risk of subsequently developing a new abnormality.