Narrow-Margin Treatment with Modified Mohs Microsurgery for Extramammary Paget's Disease: A Retrospective Clinical Analysis.

Background: To investigate the clinical efficacy of narrow-margin modified Mohs microsurgery (mMMS) in the treatment of extramammary Paget's disease (EMPD).

Methods: A retrospective cohort review was conducted on 52 patients with EMPD who were treated at the Skin Disease Hospital of Tongji University in Shanghai between 2017 and 2023. The primary objectives of this study were to assess the long-term local recurrence rates of tumors treated with narrow-margin mMMS and to explore the final margin width as well as the factors that may influence postoperative recurrence.

Results: A total of 52 patients were included in this retrospective study. Most patients were male (n = 48, 92.3%) with a mean age of 69.5 years (SD:9.08, range:44-91). The follow-up rate was 78.7% (41/52), and the mean follow-up time was 36.17 months (SD:18.25, range 5.8-62.5). The recurrence rate was 9.7% (4/41) and the 5-year tumor-free rate was 85.9%. Approximate 95% of tumors with 1 cm of non-scrotal skin extension or 1.5 cm of scrotal skin extension could be completely cleared. Univariable analysis revealed that hypopigmented patches (HR=14.0, 95% CI=1.269,154.395, p = 0.031) correlated with tumors recurrence.

Conclusion: Narrow-margin mMMS is the ideal therapy combine a disease control rate with more satisfying functional results. Determination of tumor boundaries requires attention to skin lesions with hypopigmented macules. The initial resection margins width of the extension cut can be reduced in non-scrotal skin lesions at the time of surgery to minimize pointless margin expansion.