Dermatologic surgery
Tissue-sparing properties of Mohs micrographic surgery for infiltrative basal cell carcinoma

https://doi.org/10.1016/j.jaad.2019.01.057Get rights and content

Background

Mohs micrographic surgery (MMS) should lead to tissue sparing of healthy skin compared with standard surgical excision because smaller surgical margins are used.

Objective

To quantify the tissue-sparing properties of MMS in primary basal cell carcinoma (BCC) with an infiltrative growth pattern.

Methods

A prospective study including 256 primary BCCs with an infiltrative growth pattern was performed. Tumor sizes were measured in 2 perpendicular directions. Surface defect areas after MMS were measured. The suspected defect surface area with standard excision using a 5-mm margin was calculated. The primary outcome of this study was the size of the defect surface area spared with MMS compared with the calculated defect surface area with a standard excision.

Results

The median tumor size was 71 mm2, and the median defect size after MMS was 154 mm2. The median defect size calculated for standard surgical excision was 298 mm2. We have shown that MMS of BCC with an infiltrative growth pattern had a 46.4% tissue-sparing effect when compared with standard surgical excision (95% confidence interval, 43.4%-49.1%; P value < .001).

Limitations

Single-center study design. Lack of a randomized control group for ethical reasons.

Conclusion

A rate of tissue sparing of 46% can be reached by using MMS for primary BCC with an infiltrative growth pattern.

Section snippets

Study participants

A prospective observational study in patients treated with MMS was performed at Leiden University Medical Center in 2017-2018. Patients were mostly referred by dermatologists. For all patients, the standard procedures were followed for MMS of basal cell carcinoma. The following patients were excluded: patients with recurrent or residual tumors, patients with tumors with solely a nodular or superficial growth pattern, and patients with tumors other than BCC.

Procedures

Before surgery, the tumor was measured

Results

A total of 256 tumors were removed by MMS. For patient demographics, see Table I. The median age was 70 years (range, 35-94). The average maximum tumor length was 13 mm, and the median of calculated tumor surface area was 71 mm2. The median defect size was 154 mm2. The median defect size calculated for standard surgical excision was 298 mm2. All tumors were located in the facial (n = 244) or scalp (n = 12) region (see Table II for locations). The majority of the tumors were located on the nose

Discussion

Overall, we have shown that for removal of infiltrative growing BCCs, MMS has a tissue-sparing effect of 43% to 49% compared with standard excision. In 8.6% of the tumors, standard excision with a 5-mm margin would have led to inadequate tumor removal. The tissue-sparing effect is higher for tumors on the nose and reasonably lower for tumors on the cheek and frontotemporal region (28.0% and 20.6%, respectively). The percentage of tumors in which standard excision would have led to inadequate

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Funding sources: None.

Conflicts of interest: None disclosed.

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