Invasive vulvar extramammary Paget's disease in the United States

To assess the incidence, treatment, and outcomes in patients with invasive vulvar extramammary Paget's disease (EMPD) in a national cohort of patients.

Patients from the Surveillance, Epidemiology and End Results (SEER) database with diagnoses of vulvar EMPD from 1992 to 2016 were included. Demographic, treatment, and outcome data were analyzed.

A total of 1268 cases of invasive EMPD were identified. Of those, 69.6% had localized disease, 12.0% regional disease, 1.3% distant disease, and 17.1% were unstaged. The annual incidence of invasive vulvar EMPD was 0.36 per 100,000 person years: rates have increased >2-fold since 1992 (1992: 0.19 per 100,000 person years to 0.50 per 100,000 person years in 2016). Most patients underwent primary surgery (n = 1034; 81.5%). Five-year cancer specific survival (CSS) was 95.5% and was associated with stage. Compared to patients with localized disease, patients with distant metastases had dramatically worse CSS (HR: 85.8 (31.8-248) p < 0.0001). Synchronous cancers (diagnosed within one calendar year of EMPD diagnosis year) were observed in 35 cases (2.8%), and 195 patients (15.4%) developed a secondary malignancy (diagnosed >one year from year of EMPD diagnosis year). The most common synchronous breast, gastrointestinal tract, melanoma and the most common secondary cancers were breast, gastrointestinal tract and genitourinary tract.

The incidence of invasive vulvar EMPD has increased over time. CSS is excellent for localized disease, but those with metastatic disease are in need of novel therapies. Approximately 15% will develop a secondary malignancy, indicating that patients with invasive vulvar EMPD should undergo site specific preventative health screens during recurrence surveillance.