The efficacy of curettage in delineating margins of basal cell carcinoma before Mohs micrographic surgery

Désirée Ratner, Emilia Bagiella

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37 Scopus citations

Abstract

BACKGROUND. Curettage may be helpful as a preliminary step to outline the gross subclinical extensions of high-risk basal cell carcinomas (BCCs) before the first stage of Mohs micrographic surgery. Although many Mohs surgeons use curettage in the Mohs surgical setting, no prospective studies have as yet been performed that demonstrate the efficacy of curettage in delineating tumor margins before Mohs surgery. OBJECTIVE. To document the efficacy of curettage in delineating BCC margins before Mohs micrographic surgery. METHODS. This was a prospective evaluation of 599 patients with biopsy-proven BCCs treated with Mohs surgery. The preoperative dimensions of each tumor, the curetted dimensions before the first surgical stage, the proposed excisional margins before each surgical stage, and the final defect dimensions after each surgical stage were measured. The maximum curetted margin around each tumor was calculated and compared with typical Mohs excisional margins of 1, 2, 3, and 4mm. A hypothetical 1-, 2-, 3-, or 4-mm excisional margin was added to the preoperative X and Y dimensions of each tumor, and the actual final defect sizes were compared with the hypothetical final defect sizes to determine whether an additional surgical stage would have been needed had curettage not been performed. The amount of tissue stretch occurring after specimen removal was calculated to determine whether tissue stretch falsely elevated the number of instances in which an additional surgical stage would have been needed had curettage not been performed. RESULTS. The curetted margin around the observed extent of each tumor exceeded 1 mm in 87.6% of cases, 2 mm in 47.1% of cases, 3 mm in 19.7% of cases, and 4 mm in 5.7% of cases. The mean curetted margin was 1.7 mm. Taking a 1-mm margin in the first stage of Mohs surgery without first performing curettage would have necessitated an extra surgical stage in 99.2% of cases, whereas taking a 2-, 3-, or 4-mm margin would have necessitated an extra surgical stage in 93.0%, 88.1%, and 49.4% of cases, respectively. After calculating and eliminating the effects of tissue stretch, it was found that a 1-mm excisional margin taken in the first stage of Mohs surgery without first performing curettage would have necessitated an extra surgical stage in 99.0% of the cases. Taking a 2-, 3-, or 4-mm margin would have necessitated an extra surgical stage in 87.5%, 57.9%, and 29.5% of cases, respectively. CONCLUSION. Careful debulking and palpation with the curette significantly reduce the number of Mohs surgical stages required for BCC clearance. Even after taking the effects of tissue stretch into consideration, a significant proportion of tumors would still require an additional stage for tumor clearance without aggressive presurgical curettage.

Original languageEnglish
Pages (from-to)899-903
Number of pages5
JournalDermatologic Surgery
Volume29
Issue number9
DOIs
StatePublished - 1 Sep 2003
Externally publishedYes

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