Abstract
OBJECTIVE To determine whether cleaning the cervix with a cotton swab affects the quality of the conventional Papanicolaou smear.
DESIGN Prospective, single-blinded randomized case-control study.
SETTING Two academic family medicine teaching units and 1 community family practice site.
PARTICIPANTS Female patients, 18 to 65 years of age, who presented for a routine Pap smear in the family practice setting were randomized into the Swab Group (n = 300) or the No Swab Group (n = 316).
INTERVENTION Before the Pap smear, the cervix of patients in the Swab Group was wiped with a cotton swab until visibly free of mucus. In the No Swab Group, the cervix was not cleaned with a cotton swab before the Pap smear.
MAIN OUTCOME MEASURES The quality of the conventional Pap smear was determined by the presence or absence of endocervical cells noted on the pathology report.
RESULTS There was no major difference in the quality of the Pap smear in terms of the adequacy of endocervical cells between the Swab and No Swab Group.
CONCLUSION Cleaning the cervix with a cotton swab does not appear to affect the quality of the conventional Pap smear in terms of adequacy of endocervical cells. This implies that the practice of wiping or not wiping the mucus from the cervix before taking the Pap smear can be employed at the discretion of the clinician.
The purpose of the Papanicolaou smear is to obtain cell samples from the endocervical-squamous cell junction of the cervix (ie, the area in which cervical cancer most frequently develops). During the routine performance of Pap smears, physicians often note the presence of mucus on the cervix. The effect of removing this mucus before sampling the cervical epithelium is debated. Some clinicians believe that the mucus contains a valuable proportion of the diagnostic cells that are being sampled.1 However, sampling large quantities of thick mucus onto the slide can make it difficult for the screening technician to identify the cellular component. Evidence that wiping the mucus from the cervix removes diagnostic cells and produces an inadequate sample is lacking.
Inadequate tests can result in false-negative conclusions or, if the test is repeated, cause patients anxiety, inconvenience, and resource overexpenditure. Many Pap tests are not repeated promptly, putting patients at risk of delayed diagnosis.2 In a primary care setting in British Columbia (BC), Kotaska and Matisic3 investigated the adequacy of samples after swabbing of the cervix. Using the patient’s last test as a historical control and also comparing the results with the BC statistical averages, they found a lower frequency of smears with inadequate endocervical cells in women who had the cervix cleaned with a cotton swab before the Pap smear was taken. The authors called for a prospective, randomized controlled trial to be conducted. Researchers from Wisconsin performed an analysis of adequacy using a “broom” (as is used in colonoscopy) and alternative specimen preservation techniques, dry slide or liquid immersion,1 but did not relate their results to swabbing. Addition of the cytologybrush as a routine augment to the spatula has been shown to result in a 30% decrease in the number of “inadequate” samples.4
No prospective, randomized controlled trial of cleaning of cervical mucus has been reported in the literature. We designed such a study to determine whether cleaning the cervix with a cotton swab affects the quality of the Pap smear performed in the family practice setting.
METHODS
Study design and setting
This was a prospective, single-blinded randomized case-control study. Using an odd-even numbering system, female patients presenting for a routine Pap smear were randomly assigned to the Swab Group or the No Swab Group. Randomization was performed by the family practice nurse after patient consent was obtained and before a doctor saw the patient. Neither the physicians nor the patients were blinded to the study procedure; only the pathologist was blinded to the study. The study was conducted at 2 academic family medicine teaching units in the Department of Family Medicine at the University of Alberta in Edmonton and 1 community family practice site in Edmonton, Alberta. The clinicians performing the Pap test included 13 family physicians, 24 family medicine residents, and 1 nurse practitioner. The study was conducted from June 2002 to May 2003. Ethical approval for the study was obtained from the Health Research Ethics Board at the University of Alberta.
Patients and study procedures
The study sample consisted of consecutive female patients, 18 to 65 years of age (including prenatal patients), who presented for a routine Pap smear and consented to participate in the study. Women who had a previous hysterectomy were excluded. Before the Pap smear was taken, the cervix of each patient in the Swab Group was wiped with a cotton swab until free of visible mucus. Each patient in the No Swab Group did not have her cervix wiped with a cotton swab before the Pap smear, regardless of the amount of mucus present on the cervix. Orientation sessions on the study were provided to all physicians and the nurse practitioner. This included standardization of the Pap smear procedure using both spatula and cytology brush in sequence for each test.
Data collection and outcome measures
Data were collected prospectively on a data-collection form clipped on top of patients’ charts. The family practice nurse noted on the form the patient’s age, menopausal status, and the study group into which the patient had been randomized. At the time of the Pap smear, the physician recorded the appearance of the cervix in terms of its redness (normal, moderately red, or beefy red), friability (normal, friable, or very friable), and atrophy (yes or no), as well as the amount of mucus present on the cervix (dry cervix, light mucus, or heavy mucus). The degree of severity of these conditions of the cervix was based on the subjective clinical assessment by the physician. When the pathology report was available, the study nurse obtained from the specimen report the following data: the quality of the Pap smear, the result of the Pap smear, and whether a repeat Pap smear was required. The quality of the Pap smear was determined by the presence or absence of adequate numbers of endocervical cells noted on the pathology report. An “inadequate” specimen report indicated that no or very few cells of any kind were present, and “adequate, but limited” was defined as having good cellular component (presence of other cells sampled), but no or very few endocervical cells seen. The former would suggest that a repeat smear be performed, and the latter would require a clinical decision on risk to determine how soon the next smear test would be indicated. Either case was reported by the pathologist as “repeat Pap smear required.”
Data analysis
Data analysis was performed using SPSS 12.0 for Windows and consisted of frequencies and summary statistics. Differences between the 2 groups were tested using χ2 and the Fisher exact test, where appropriate. An α level of .05 was used to test for statistical significance. With a power of 80% and an α level of .05, our study sample size was sufficient to detect a reduction of greater than 46% in inadequate smears from the 1998 Alberta provincial baseline of 15%.4
RESULTS
There were 772 consecutive patients approached to take part in the study. A total of 156 (20%) declined or were excluded. Seventy (45%) of these 156 were excluded because of previous hysterectomy. A total of 616 patients were recruited into the study (ie, 300 in the Swab Group and 316 in the No Swab Group). The 2 groups were similar in age, menopausal status, the redness, friability and atrophy of the cervix, and the amount of mucus on the cervix (Table 1). There was no significant difference in the quality of the Pap smear in terms of the adequacy of endocervical cells between the Swab and No Swab Groups (Figure 1). The rate of repeat Pap smears, as recommended by the pathologist, was similar between the groups (ie, 28.3% in the Swab Group and 25.0% in the No Swab Group). The main reason for recommended repeat Pap smears was limited cellular component (14.3% and 10.8%). Cellular changes accounted for 7.7% and 9.5% and other factors, such as patient’s previous history, for 6.3% and 4.7% (Table 2).
Swabbing or not swabbing in the presence of varying degrees of mucus present did not affect the adequacy of endocervical cells (Table 3). There was also no difference between the groups in terms of adequacy of endocervical cells controlling for age, menopausal status, and friability, redness, or atrophy of the cervix.
DISCUSSION
This prospective, single-blinded randomized trial found that cleaning the cervix with a cotton swab before taking the Pap smear sample did not affect the adequacy of endocervical cells on the conventional Pap smear. These findings are consistent with another study that reported no statistically significant difference in the quality of the Pap smear, in terms of adequacy of endocervical cells, when using a Weck-cel sponge to collect endocervical secretions.5 Our findings differ, however, from those of a recent Canadian study that found an association between cleaning with an oversized cotton swab and a lower frequency of smears with inadequate endocervical cells.3
Current guidelines of the Alberta Medical Association are undecided on the wiping of the cervix. They state that “excess mucus on the cervix may be removed with a cotton swab prior to sampling if this is a problem.”6 Our study findings do not refute this position.
The necessary repeat of Pap tests because endocervical cells are absent from the sample is not a minor problem. Patients are inconvenienced by having to return and also by undergoing the procedure again. Their anxiety about the importance of the inconclusive result often must be addressed by clinicians. The repeat test rates of 14.3% and 10.8% because of sampling issues are a marker of considerable patient distress.
It seems that the risk of removing diagnostic cells by swabbing is balanced by removing thick impenetrable mucus that the technician cannot see through. It might seem reasonable to advise removing heavy mucus and not swabbing a dry cervix, but the number of dry cervices in our study does not allow us to comment on this (Table 3).
This study had some limitations. The specific elements of the study design are strengths of this clinical trial. However, the numerous clinicians who performed the Pap smears, while reflecting the real-world situation, might have jeopardized the standardization of the Pap smear technique. Despite clinicians’ standardized training, heterogenous Pap smear techniques among clinicians might have contributed to non-significant findings. There might have been interobserver discrepancy in the subjective assessment by each clinician of the friability, redness, and amount of mucus on the cervix, thereby resulting in non-significant findings for these characteristics. The study findings apply only to conventional Pap smears and not to those obtained using liquid-based cytology. Furthermore, the study examines only a single outcome (smear adequacy) and not the comparative sensitivity of samples taken with or without swabbing.
Future studies should include randomization, multiple clinicians, and a larger sample size. If heterogenous techniques did jeopardize standardization of Pap smear techniques, better training might be required. The study should be repeated in another setting to confirm our findings.
CONCLUSION
Cleaning the cervix with a cotton swab does not appear to affect the quality of the Pap smear in terms of adequate samples of endocervical cells. This implies that the practice of wiping or not wiping the mucus from the cervix before taking the Pap smear can be at the discretion of the clinician.
Acknowledgment
We thank Mary Wittenberg for data entry and Shufen Edmondstone for secretarial assistance. The findings of this study were presented at the North American Primary Care Research Group (NAPCRG) meeting in Orlando, Fla, on October 12, 2004.
Notes
EDITOR’S KEY POINTS
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When performing conventional Papanicolaou smears, physicians frequently encounter mucus overlying the cervix. Some believe that the mucus contains valuable diagnostic cells, while others believe that the mucus will obscure the cellular component on the slide.
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This randomized study found that swabbing or not swabbing made no difference in the quality of the conventional Pap smear.
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The authors caution that there are some limitations to their study, which include possible heterogeneity in Pap smear technique by the numerous physicians who participated in the study. They recommend that the study be repeated in another centre with a larger sample size.
POINTS DE REPÈRE DU RÉDACTEUR
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Lors d’un frottis de Papanicolaou conventionnel, les médecins sont souvent en présence de mucus sur le col de l’utérus. Certains croient que le mucus contient des cellules utiles dans le diagnostic, tandis que d’autres sont d’avis que le mucus brouille la composante cellulaire sur la lame.
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Dans cette étude randomisée, on a constaté qu’avec ou sans écouvillon, la qualité du frottis de Pap conventionnel était la même.
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Les auteurs avertissent les lecteurs que leur étude comporte certaines limites, notamment l’hétérogé-néité de la technique du frottis de Pap, étant donné le grand nombre de médecins qui ont participé à l’étude. Ils recommandent que cette étude soit refaite dans un plus grand centre, auprès d’un plus important échantillonnage.
Footnotes
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This article has been peer reviewed.
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Contributors
Dr Hans was involved in the conceptualization of the study, development of the study design, data analysis and interpretation, and review of the manuscript. Dr Cave was involved in the conceptualization of the study, development of the study design, development of the data-collection form, data analysis and interpretation, and writing and reviewing the manuscript. Ms Szafran provided methodological support to the project and was involved in the development of the data-collection form, data anlaysis, and writing and reviewing the manuscript. Dr Johnson participated in the conceptualization of the study, development of the study design, overseeing the pathology testing, and reviewing the manuscript. At the time of the study, Ms Glass was the research nurse who collected the data and reviewed the manuscript. Drs Spooner, Klemka, and Schipper participated in the conceptualization of the study, development of the study design, interpretation of the study findings, and review of the manuscript.
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Competing interests
This project was funded by the Grey Nuns Family Medicine Research and Education Fund.
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