A Critical Evaluation of the Endocervical Curettage

Nick M. Spirtos, MD, John B. Schlaerth, MD, Gerrit d'Ablaing III, MD, and C. Paul Morrow, MD

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Despite the widespread use of the endocervical curettage in the management of abnormal cervical cytology, there has been little critical study of its proper role. In patients with satisfactory colposcopic examinations, the frequency of a positive endocervical curettage from ectocervical contamination (false positive), from sampling "skip lesions," or from an inaccurate assessment of the squamocolumnar junction is unknown. False-negative findings have never been quantified in detail. In several widely quoted algorithms for managing abnormal cervical cytology, endocervical curettage results are pivotal in determining management choices (1-9). Because the sensitivity and specificity of this procedure are poorly understood, patients may be subjected to unnecessary medical costs, delays, risks, and complications. This prospective study was undertaken to better assess the value of the endocervical curettage.

Materials and Methods

From July 1, 1984 to July 30, 1985, 586 patients with cytologic evaluation consistent with cervical intraepithelial neoplasia or invasive cancer were evaluated in the Gynecologic Oncology Clinic at Los Angeles County/University of Southern California Medical Center. Two hundred sixty-one of these patients had colposcopically identifiable lesions, no previous cervical biopsies, and no gross cervical lesions suspicious for invasive carcinoma.

After repeat cervical cytology was obtained, the endocervical canal was sampled using a saline-moistened, cotton-tipped applicator, and the ectocervix was scraped with a plastic spatula. Coposcopy, performed by house staff under the direct supervision of one of the authors (NMS), was considered satisfactory if the full extent of the cervical lesion and the entire transformation zone were visible. The examination was classified as unsatisfactory if the entire cervical lesion and transformation zone were not visualized. After identifying and grading the ectocervical lesion, we performed a thorough, circumferential endocervical curettage. A second colposcopic examination followed, during which we noted whether the endocervical curettage had disrupted the ectocervical lesion. finally, the ectocervical lesion was biopsied and a pelvic examination performed.

Table 1. Population Characteristics and Diagnoses

CIN = cervical intraepithelial neoplasia.

Biopsy specimens were fixed in 10% formaldehyde. Paraffin sections were stained with hematoxylin and eosin (H&E). A single pathologist (Gd'A) reviewed all histologic sections. The specimens were categorized into seven groups: koilocytotic atypia; cervical intraepithelial neoplasia I, II and III; early stromal invasion; microinvasion; and invasive cancer.

We used the morphologic characteristics of cervical condyloma as defined by Meisels et al (10) to identify koilocytotic atypia. Cervical intraepithelial neoplasia was graded as I, II, or III using Richart's (11) criteria. The histologic criteria of Sedlis et al (12) and Lohe (13) were applied in interpreting early stromal invasion and microinvasive carcinoma. Depth of invasion was measured in microns using a Peak 15X scale loupe. We used the Society of Gynecologic Oncologists' classification of stage IA cervical carcinoma.
Invasive cervical carcinoma was classified by cell type using the pathology definitions of Reagan and Ng (14). It was also determined at review whether the endocervical curettage yielded sufficient material for a definitive diagnosis. All cases were reviewed weekly at a gynecologic oncology pathology conference.

Variables recorded included age, gravidity, parity, satisfactory/unsatisfactory colposcopy, cervical cytology, colposcopic interpretation, and histologic grading of all biopsy specimens. We also noted whether the ectocervical lesion had been disrupted by the endocervical curettage. Information from the second colposcopic examination was not used in making management decisions. Statistical significance was established using X2 calculations.

Results

Table 1 summarizes the characteristics of the patient population, including their final histopathologic diagnosis. Two hundred ten women (80%) had satisfactory and 51 (20%) had unsatisfactory colposcopic examinations. Patients who were over 40 years of age, were grand multipara, or had a highly dysplastic lesion (cervical intraepithelial neoplasia III or worse) had a significantly higher rate (P < .01) of unsatisfactory colposcopic examinations.

Of the 210 patients with satisfactory colposcopic examinations, 20 (9.5%) were noted during the postendocervical curettage colposcopy to have disruption of the ectocervical lesion. Ten of these 20 women had endocervical curettages diagnostic for dysplasia. Every patient with a positive endocervical curettage showed an ectocervical lesion that had been disrupted by the procedure (Figure 1). Five of the ten patients with positive endocervical curettage underwent conization. Review of the histologic sections from the cone biopsies of all five cases revealed that all identifiable dysplastic tissue was limited to the colposcopically evaluable transformation zone. The remaining five patients were spared conization and treated with cryosurgery (Table 2). Follow-up of at least 18 months, which consisted of colposcopy and cytologic evaluation, has revealed no evidence of persistent or recurrent dysplasia. Patients were scheduled for quarterly follow-up visits during the first year and biannual visits thereafter. All have had at least three follow-up examinations over the 18 months. The other ten patients with disrupted ectocervical lesions had endocervical curettages that revealed only benign endocervical tissue. In the study group as a whole, the endocervical curettage had to be repeated in six patients because the initial sampling retrieved an insufficient amount of tissue, and in four patients because it revealed endometrium only.

Fifty-one patients had an unsatisfactory colposcopic examination. All 51 had endocervical curettages, and 39 (76%) underwent conization. Of the remaining 12 patients, seven had either an endocervical curettage or a cervical biopsy demonstrating invasive cancer, and therefore did not need conization; four patients had nondysplastic lesions; and one patient was lost to follow-up. In this group of patients, 12 endocervical curettages (24%) were falsely negative, three (6.5%) yielded an insufficient amount of tissue to make a diagnosis, and one yielded only endometrial tissue.

Of the 39 women with unsatisfactory colposcopy who underwent cone biopsy, four (10%) had evidence of invasive lesions. Two of these patients had ectocervical and endocervical biopsies diagnostic for cervical intraepithelial neoplasia III only. One had an insufficient amount of tissue recovered on endocervical curettage, and an ectocervical biopsy consistent with cervical intraepithelial neoplasia III. The final patient's ectocervical biopsy specimen revealed cervical intraepithelilal neoplasia III, and her endocervical curettage yielded only endometrial tissue. All 12 patients with invasive cancer had unsatisfactory colposcopic examinations. (Table 3).

Overall, 44 patients-39 with unsatisfactory colposcopy and five with satisfactory colposcopy-underwent conization. An additional seven patients, all with unsatisfactory colposcopy and biopsy-proved invasive cancer, underwent radical hysterectomy and bilateral pelvic lymph node dissection. Thus, we were able to compare the histology of the endocervical curettage with the cone biopsy or hysterectomy specimen in 51patients. In no case was the grade of neoplasia more severe in the endocervical curettage than in the definitive specimen.

Table 2. Ten Patients With Satisfactory Colposcopy
and Positive Endocervical Curettage

CxBx = cervical biopsy; ECC = endocervical curettage; CIN = cervical
intraepithelial neoplasia; NMC = no malignant cells.

Table 3. Role of Cone Biopsy, Endocervical Curettage,
and Cervical Biopsy in the Diagnosis of Invasive Cancer

Ecto CxBx = ectocervical biopsy; ECC = endocervical curettage; CIN = cervical
intraepithelial neoplasia; Inv ca = invasive cancer; Inflam = inflammation;
QNS = quantity not sufficient.
* All patients with cancer had unsatisfactory colposcopy.
† Cases in which CxBx and endocervical curettage alone or in combination
could have resulted in significant undertreatment.

Discussion

This prospective examination of the endocervical curettage allowed us to reasonably assess this procedure as an isolated variable in patients who had not undergone previous treatment. In this study, the endocervical curettage was falsely positive in 4.7% of cases. By determining whether the ectocervical lesion was damaged at the time of endocervical curettage, we were able to test the null hypothesis that a positive endocervical curettage in a patient with a satisfactory colposcopic examination is not due to ectocervical contamination. Since every positive endocervical curettage was associated with a disrupted ectocervical lesion (Figure 1), X2 analysis was significant at (P <.005), and the null hypothesis was rejected. As a result, it is reasonable to conclude that a positive endocervical curettage in a patient with a satisfactory colposcopic examination is most likely the result of contamination. Other indirect evidence supports this conclusion. Several investigators have consistently reported that more patients with satisfactory colposcopic examination had positive endocervical curettages (Table 4) (2,3,6,8). However, our methods differed in that the endocervical curettage preceded ectocervical biopsy. Performing a biopsy before the endocervical curettage, as other investigators have done, results in fragmented ectocervical lesions and a higher likelihood of a contaminated endocervical curettage. This difference in methods could account for the difference in results, and again suggests that contamination causes a positive endocervical curettage in the patient with a satisfactory colposcopic examination.

Table 4. Frequency of Positive Endocervial
Curettage in Patients with Satisfactory Colposcopy

CIN = cervical intraepithelial neoplasia.

The postendocervical curettage colposcopic examination used in this study suggests that contamination is a common cause of a positive endocervical curettage in this setting. However, it would be dangerous to make inferences about the frequency of "skip lesions" from this second colposcopic examination. The incidence and topography of these lesions can best be studied by diagnostic cone biopsies performed on women with abnormal cervical cytology in whom the endocervical curettage has been omitted. Such a study would likely be regarded as a retrogressive step in the management of preinvasive cervical lesions. It is also unlikely to resolve the dilemma. For our purposes, the postendocervical curettage colposcopic examination provides an additional piece of information that is usefulwhen deciding whether to perform a diagnostic cone biopsy in young, fertile women with satisfactory colposcopy and a positive endocervical curettage.

Based on the present study , we recommend that the examining physician do the following: 1) perform an endocervical curettage, 2) check for disruption of the ectocervical lesion, and 3) repeat the evaluation and the endocervical curettage in three to four months, before instituting definitive therapy, if the endocervical curettage is positive. Richart (15) has simlarly suggested repeating the endocervical curettage and managing such patients conservatively.

By definition, the 51 patients with unsatisfactory colposcopic examinations had lesions in the endocervical canal that extended at least far enough so that the entire lesion could not be visualized. Assuming that the practitioner has reasonable skill, most if not all of these patients should have a positive endocervical curettage. Sixteen (30.6%) had either no dysplastic tissue, only endometrium, squamous metaplasia, or an insufficient amount of tissue to make a histologic diagnosis. Other groups have reported false-negative rates between 41-45% in patients with unsatisfactory colposcopy.( 2-4,6) The similarity in results among many groups is probably due to simlarity in technique or, even more significantly, to the limitations of the procedure.

Further analysis of our data confirms that conization is necessary to evaluate fully the patient with an unsatisfactory colposcopic examination. At least two and possibly four invasive cancers would have been missed if the diagnosis had been based on the results of the endocervical and ectocervical biopsies, either alone or in combination (Table 3). These findings confirm the data of Townsend et al and suggest that conservative treatment, as suggested by Hatch et al, may result in significant undertreatment. (1,3,6) Endocervical curettage did avert cone biopsy in two patients with unsatisfactory colposcopy; in these two cases, the endocervical curettage demonstrated invasive cancers that were not diagnosed by ectocervical biopsy. In addition, it should be noted that because the grade of neoplasia was never worse in the endocervical curettage than in the definitive specimen, the endocervical curettage did not result in overtreatment of any patient. In this respect, our data confirm the findings of other investigators. (2,6)

References

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