Management choices for patients with "squamous atypia" on Papanicolaou smear. A toss up?

Appropriate management of borderline abnormalities on Papanicolaou (Pap smears is controversial. This decision analysis compared two strategies for management of women with the Pap smear result of "squamous atypia." A policy of immediate colposcopy and biopsy was compared with repeating the cervical smear at 6-month intervals. Relevant probabilities and ranges were extracted from published studies in the English language medical literature from 1966 to 1993. When no relevant studies could be located, probabilities with a plausible range were determined through consensus of a panel of experts. Outcome values were assigned for the analysis to contrast the time period (approximately 2 years) covered by the analysis. Using baseline estimates, either policy resulted in an essentially equivalent probability of invasive cervical cancer. The estimated likelihood of remaining free of invasive cervical cancer was .9974 for follow-up by repeat smear versus .9976 for immediate colposcopy and biopsy. In sensitivity analysis, very high probabilities of progression to invasive cervical cancer favored the policy of immediate colposcopy and biopsy. Follow-up of squamous atypia on cervical smear by repeating the smear at 6-month intervals is unlikely to result in a detectable increase in invasive cervical cancers.