Outcome after a Pap smear report of low-grade abnormality: a longitudinal comparative study.

The rate of subsequent diagnosis of high-grade cervical abnormality was studied among women whose first Pap smear in 1994 was reported as being negative or from the category of low-grade abnormality (excluding CIN 1). Regardless of the degree of low-grade abnormality reported on the entry smear, the rate of subsequent high-grade disease was 3.3 cases per 100 years of follow-up. The rate of subsequent high-grade disease among women with negative Pap smear reports was 0.23 to 0.45 cases per 100 years of follow-up. Within each cohort, a small number of cases of invasive cervical cancer were diagnosed in the 2 years after the entry smear. These data indicate that Pap smear reports which are coded to the registry squamous cell code of 'mild atypia' (with or without evidence of human papillomavirus effect) have a significantly higher risk of emerging high-grade cervical disease than negative Pap smear reports (including those with minor reactive and/or inflammatory change). It is suggested that the former have a uniform recommendation of repeating the smear in 1 year and the latter in 2 years.