Empiric Vaginal Metronidazole in the Management of the ASCUS Papanicolaou Smear

Abstract

In Brief OBJECTIVE To determine whether empiric treatment with vaginal metronidazole in women with atypical squamous cells of undetermined significance (ASCUS) on Papanicolaou smear increases the number of cases that regress to normal on repeated cytologic studies. METHODS A randomized double-masked trial was designed to compare women with ASCUS on screening Papanicolaou smear who received vaginal metronidazole, 37.5 mg twice daily, or placebo gel twice daily, for 5 days. Normalization of repeated Papanicolaou smear at 3 months was the primary end point. Regression to normal between the two groups was compared by χ2 analysis. Power analysis required 45 women per study arm to demonstrate a 50% improvement in regression to normal among the metronidazole-treated women, at α = 0.05 and 80% power. RESULTS One hundred and six tubes of gel were dispensed, 54 metronidazole and 52 placebo. Eighty-four women (79%) returned for repeated cytologic examination at a mean of 6.5 months. Overall, 50 women (60%) had normal findings on repeated cytologic examination, and 34 (40%) had persistent abnormal findings. Twenty-two women had repeated ASCUS, and 11 had squamous intra-epithelial lesions (SIL) on repeated cytologic examination. Regression to normal was found in 22 (54%) metronidazole-treated women and 28 (65%) placebo recipients. The number of cases of repeated ASCUS (31% versus 25%) or SIL (15% versus 10%) were similar between the two groups. CONCLUSIONS Empiric vaginal metronidazole does not improve the management of women with ASCUS on Papanicolaou smear and should be discouraged. Empiric use of vaginal metronidazole after a Papanicolaou smear diagnosis of ASCUS does not improve the rate of normal results on repeated cytologic studies.