Background/aim: Extramammary Paget's disease (EMPD) is a rare, slow growing intra-epidermal malignant neoplasm that arises in areas rich in apocrine glands. Several common sites of occurrence have been reported, including the vulva, perianal region, perineum, and scrotum. Most relevant studies rely on small data bases. Our objective was to evaluate prognostic factors of EMPD patients at a single medical center.

Patients and methods: We retrospectively analyzed 19 patients (8 males, 11 females) diagnosed with genital EMPD who were treated at the Taichung Veterans General Hospital between 2006/04 and 2022/08. Collected information included tumor location, margin condition in the case of surgical resection, recurrence rate, recurrence management, accompanied gastrointestinal malignancy, treatment details and survival data.

Results: Among 19 cases, 4 with initial margin being positive, and 3 received second surgery (one refused surgery and another expired within a year). Tumor recurrence was found in 7 cases, with 6 of them later receiving second surgery, and the remaining one received radiation therapy. Median DFS was 7.57 years. During the 15-year follow-up, 2 patients expired. Overall survival rate was 87.5%. Among all factors we had analyzed, only those accompanied with GI tract malignancy had significantly worse survival rate (p=0.018). Frozen sections taken at surgical margin during surgery significantly reduced cancer recurrence rate (p=0.45). Permanent pathology margins appeared to affect the recurrence rate, but that was not significant when comparing with intraoperative frozen sections.

Conclusion: Local wide excision with skin flap reconstruction remains the major treatment option for genital EMPD. Following the standard-of-care procedure, the overall patient outcome was excellent. Among factors potentially associated with recurrence rate, intraoperative frozen biopsy was the most significant one. Performing intraoperative frozen biopsy is essential for recurrence-free rate elevation.