A matter of margins: Surgical and pathologic risk factors for recurrence in extramammary Paget's disease.

OBJECTIVES: To determine surgical and pathologic variables associated with recurrence in extramammary Paget's disease (EMPD).

METHODS: Medical records of patients seeking care for EMPD from 1/1992-9/2015 were reviewed. Follow-up was restricted to 5years following primary surgery. Recurrence-free survival (RFS) was estimated using the Kaplan-Meier method. Risk factors were evaluated for an association with recurrence and positive margins, respectively, using Cox proportional hazards regression and logistic regression.

RESULTS: Of 154 patients, 90 (58.4%) were female and 65 (41.6%) were male. Treatment consisted of wide local excision (WLE, includes WLE or radical vulvectomy, 77.3%), Mohs micrographic surgery (MMS, 19.5%), and abdominoperineal resection (3.2%). RFS at 1, 3, and 5years was 84.5% (95% confidence interval (CI), 78.2-91.4%), 66.1% (95% CI, 57.5-75.9%), and 56.1% (95% CI, 46.9-67.1%), respectively. Positive surgical margins were univariately associated with higher risk of recurrence (HR 3.55, 95% CI 1.74, 7.24). Margin status significantly correlated with procedure type (33.3% vs. 3.4% had positive margins with WLE vs. MMS, p=0.01). Among patients with negative margins, there was a 2.5 fold increased risk of recurrence after WLE compared to MMS (95% CI, 0.57-10.9, p=n.s.).

CONCLUSION: Inclusion of males allowed us to examine the influence of a different surgical approach (MMS) on margin status and recurrence rates in EMPD. In contrast to prior studies including solely vulvar EMPD, we observed strong association between margin status and recurrence risk. Risk of positive margins was significantly higher after WLE compared to MMS. MMS should be explored to improve outcomes in gynecologic patients with EMPD.