Prognostic Factors of Extramammary Paget's Disease.

OPINION STATEMENT: Most patients with extramammary Paget's disease (EMPD) show a good prognosis; however, some patients develop fatal metastases. Early detection is important for improving prognosis, due to the difficulties associated with the treatment of distant EMPD metastases. Several studies have emphasized the importance of the invasion level of the primary lesion for predicting the presence of metastasis, and deeper invasion or increased thickness is correlated with poorer prognosis. Vascular tumor invasion of the primary lesion can also predict the risk of metastasis. Lymph node metastasis is a strong indicator for poor prognosis, and the number of lymph node metastases affects patient outcome, in that there is a significant difference in survival between patients with zero or one lymph node metastasis and those with more than two lymph node metastases. Serum markers may be able to predict the presence of systemic metastases, and carcinoembryonic antigen and cytokeratin 19 fragment 21-1 reflect disease progression and may be clinically valuable. Although several genetic alterations have been determined for EMPD, factors determining prognosis should be further explored.