A Glint of Hope for Treatment of Advanced Malignant Transformations of Ovarian Mature Cystic Teratomas: A Retrospective Analysis of 9 Cases

Objective: Malignant transformation of a mature cystic teratoma (MTMCT) of the ovary is extremely rare; the occurrence rate is ~1%-3% of all mature cystic teratomas. Because of the rarity of MTMCT, there are many unknown aspects of its clinical findings, treatment, and prognosis. Prognosis for MTMCT is reportedly worse than that of epithelial ovarian cancer. A retrospective study was performed with 9 patients in the Gynecology Service, of the National Kyushu Cancer Center, in Fukuoka, Japan, to explore MTMCT's clinical findings and prognosis. Materials and Methods: This was a retrospective study of nine cases of MTMCT treated in the hospital from January 2000 to December 2017. Results: The median age of the 9 patients was 65. The median survival time was 20.5 months (range: 11-127 months). Among the patients, 5 (55.5%) were determined to have advanced stage III or IV MTMCT. All patients underwent hysterectomy with bilateral salpingo-oophorectomy and omentectomy. Five patients (55.5%) underwent more-extended debulking surgery, including intestinal-tract and ureter resection. All patients received postoperative adjuvant treatments. Unexpectedly, however, 3 of 5 patients with advanced disease (stage III/IV) survived for more than 5 years. None of the surviving patients developed recurrences after the initial treatment. Conclusions: MTMCT is a malignant disease with a poor prognosis even in the early stage. However, some patients with advanced MTMCT can have long-term survival even with poor prognostic factors, such as lymph-node metastases and intestinal invasions. The prognosis may be improved by performing maximal tumor reduction and appropriate adjuvant therapy. (J GYNECOL SURG 36:184).