Surgeons in academic settings reported taking larger average first-stage margins on the head/neck (6.70 mm vs 4.17 mm, p =.05) and on the hands/feet (8.00 mm vs 3.75 mm, p =.01)
Clinical Pearls
A greater proportion of academic surgeons reported use of cytokeratin-20 (CK-20) immunohistochemical stain when compared with private practitioners (50% vs 5.6%, p =.01).
Surgeons in academic settings reported taking larger average first-stage margins on the head/neck (6.70 mm vs 4.17 mm, p =.05) and on the hands/feet (8.00 mm vs 3.75 mm, p =.01).
Surgeons practicing in academic settings were more likely than their private practice counterparts to cite institutional guidelines (40.0% vs 0.0%, p =.01) and multidisciplinary tumor boards (50% vs 5.6%, p =.01).
Discussion:
Merkel cell carcinoma (MCC) is an aggressive malignancy derived from neuroendocrine cells that holds a high rate of local recurrences and metastases. The established standard of care at this time is wide local excision, however data shows that Mohs Micrographic Surgery (MMS) may be non-inferior to wide local excision. In cosmetically sensitive locations specifically, MMS may be useful in enabling negative confirmation of margins and minimizing defect size. However, the practice patterns and technique of surgery may vary among dermatologic surgeons.
This study was performed as a cross-sectional survey targeting Mohs surgeons with membership in the American College of Mohs Surgery. An 18-question online survey was delivered through the ACMS mailing list from June 2022 to July 2022. Chi-square, Fisher’s exact, and Wilcoxon rank sum tests were used to compare differences between respondents from academic and private practice settings.
There was a total of 55 respondents, with (n=38, 69.1%) from private practice settings and (n=17, 30.9%) from academic settings. Of note, six respondents from academic settings were involved in mixed practice. Approximately 50.9% of respondents detailed use of MMS for MCC, without significant difference between academic and private practice settings. In regards to rationale for not applying MMS for these cases, lack of evidence demonstrating superior outcomes, lack of access to immunostains, absence of training during fellowship, lack of referrals and high recurrence rates were the most commonly cited reasons.
Among surgeons treating MCC with MMS, 90% in academic settings reported excising a debulk specimen for vertical sections at least 25% of the time, compared with only 44.4% of private practitioners (p =.02). A greater proportion of academic surgeons reported use of cytokeratin-20 (CK-20) immunohistochemical stain when compared with private practitioners (50% vs 5.6%, p =.01). Surgeons in academic settings reported taking larger average first-stage margins on the head/neck (6.70 mm vs 4.17 mm, p =.05) and on the hands/feet (8.00 mm vs 3.75 mm, p =.01). Surgeons practicing in academic settings were more likely than their private practice counterparts to cite institutional guidelines (40.0% vs 0.0%, p =.01) and multidisciplinary tumor boards (50% vs 5.6%, p =.01). Seventy-five percent (n 5 21) of surgeons did not confirm clear MMS margins with permanent section, whereas 17.9% thawed frozen section margins and 7.1% excised additional margins for permanent sections.
This study is useful in demonstrating the variation in use and technique of MMS for Merkel Cell Carcinoma in fellowship-trained dermatologic surgeons. Limitations include a small response rate, selection bias, recall bias, and limitation in survey studies. Further studies investigating the use of MMS for MCC will be useful to dermatologists in decision making regarding this aggressive malignancy.
Comments