Endometrial papillary serous carcinoma: patterns of spread and treatment.

Uterine papillary serous carcinoma exemplifies the potential for Müllerian epithelium at any site to differentiate along histologic patterns that replicate Müllerian epithelium at other sites, especially when neoplastic. Papillary serous differentiation is most commonly associated with epithelial ovarian carcinoma. Papillary serous differentiation of endometrial malignancy is associated with a poor prognosis wrought mainly through the tendency to present as late- stage disease. There is a considerable discrepancy between clinical and surgical staging. Because surgical stage is the single most important prognostic factor, the need for standardized, accurate, and comprehensive staging is highlighted, particularly where experimental protocols are being evaluated. Similarly, there is a need for strict adherence to standardized histologic criteria and reporting, particularly in making the often subtle distinction between papillary endometrioid adenocarcinoma and UPSC. Because even the earliest stage of disease is associated with a poor prognosis, a case can be made for offering adjuvant therapy to all patients diagnosed with UPSC. No single adjuvant modality has emerged as preeminent. There is comparable response to both radiotherapy and chemotherapy regimens, suggesting a need to compare these regimens in a multicenter, randomized trial. Because UPSC constitutes up to 10% of all endometrial carcinomas, there should be no difficulty accruing sufficient numbers for meaningful analysis. Although such a study may provide clues to optimizing available adjuvant strategies, further improvement in treatment regimens is required to effectively alter the poor prognosis associated with this condition.