Treatment Selection Based on Dominant Tumor Biology in Endometrial Carcinoma with Choriocarcinomatous Differentiation: A Case-Based Review.

Endometrial carcinoma (EC) with choriocarcinomatous differentiation is an exceptionally rare malignancy for which standardized postoperative treatment strategies are lacking. Herein, we describe two postmenopausal patients with endometrioid carcinoma containing a choriocarcinomatous component. One patient had an EC-dominant tumor with low and rapidly normalized postoperative serum human chorionic gonadotropin (hCG) levels and received paclitaxel plus carboplatin. The other patient had a choriocarcinomatous-dominant tumor with markedly elevated postoperative serum hCG levels and was treated with gestational trophoblastic neoplasia (GTN)-oriented chemotherapy using etoposide, methotrexate, actinomycin D/cyclophosphamide, and vincristine (EMA/CO). Both patients remain disease-free. A review of representative published cases revealed two competing treatment paradigms, EC-oriented and GTN-oriented, applied inconsistently and without unified selection criteria. On the basis of integrated clinicopathological assessment, we propose that postoperative treatment consideration should be guided primarily by dominant tumor biology, rather than the International Federation of Gynecology and Obstetrics stage alone. Tumors with a dominant choriocarcinomatous component accompanied by elevated postoperative serum hCG levels may benefit from GTN-oriented chemotherapy, whereas EC-dominant tumors with low or normalized hCG levels may benefit from EC-oriented regimens. Reassessment of dominant tumor biology using postoperative pathological findings and serum hCG dynamics may provide a pragmatic, decision-support framework for adjuvant treatment consideration in this rare and clinically challenging entity.