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Abstract & Commentary
Synopsis: Empiric vaginal metronidazole should not be used in the management of patients with ASCUS Pap smears.
Source: Connor JP, et al. Obstet Gynecol. 2002;99: 183-187.
The purpose of this study was to determine whether women with ASCUS Pap smears who had no evidence of bacterial vaginosis had fewer abnormal repeat smears if empiric treatment with vaginal metronidazole was prescribed. Conner and associates mention that the practice of using a vagina antibiotic following a minimally atypical Pap smear is widespread. They also had reviewed the literature and found no evidence to support such therapy. The only prospective randomized trial in the literature compared use of vaginal triple sulfa cream to no treatment. Vaginal metronidazole had not previously been used in a placebo-controlled trial.
One hundred ninety-seven women were eligible for consideration for entry into this study. The population was chosen from an inner-city gynecologic clinic. In order to be a study participant, the woman had an ASCUS Pap smear, was 18 years of age or older, had no other abnormal cytology in the prior year, had no history of lower genital tract infection in the past month, had no antibiotic use in the past month, and was not pregnant. After the study was discussed with the potential participants, each underwent a speculum examination. Proper techniques were used to exclude the presence of bacterial vaginosis, trichomonas, or candidiasis. One hundred six women met entry criteria and were not excluded by initial examination. Each received either metronidazole vaginal cream or a placebo in an unmarked tube. Neither the study participants nor the physicians knew which tubes contained the active ingredient.
Demographic variables were virtually identical for the treatment and placebo groups. Eighty-four women (41 metronidazole and 43 placebo participants) returned for repeat Pap smear. Fifty of these 84 had normal cytology and 34 had persistent abnormal findings. Fifty-four percent of the women who received the active ingredient and 65% of those who received placebo had a repeat normal cytology. Women in both groups who had abnormalities on the repeat smear were referred for cytology. There were no differences in the findings of CIN between the 2 groups among those women who appeared for colposcopy.
Conner et al conclude that there is no role for the empiric use of vaginal metronidazole following an initial ASCUS Pap smear.
For more than 25 years, I have had a referral colposcopy practice. During that time I have heard an unbelievable wide array of tests and procedures that were performed prior to the patient being sent to me. Among those women who had repeat minimal abnormal smears (previously Class II and now ASCUS), the one constant has been that most had received some type of antibacterial vaginal cream prior to their repeat Pap smear. In years past the cream of choice was a triple sulfa preparation, and more recently it has been either metronidazole or clindamycin vaginal cream.
I have always wondered why such treatment is so common, since there is no literature to support the practice. I strongly suspect that it goes back to the old Papanicolaou classification system of Pap smears in which a "Class II" smear was more or less equated with "inflammation." Perhaps clinicians think that by using an antibiotic cream the inflammation resolves and the Pap smear will more frequently revert to normal. Although the change to the Bethesda system took inflammation out of the category of squamous abnormalities (and inflammation should not be the cause of an ASCUS smear), I suspect that old habits are hard to break. Unfortunately, a lot of young practitioners also routinely use vaginal antibiotic cream after a minimally atypical Pap smear.
I firmly believe that the results of this study, and the previous study using triple sulfa cream, should convince even the most skeptical clinician that there is no place for the empiric use of vaginal antibiotic creams in an attempt to revert a minimally atypical Pap smear to normal. The practice is costly, inconvenient, and potentially dangerous.
Dr. Noller is Professor and Chairman Department of OB/GYN, Tufts University School of Medicine, Boston, Massachusetts.