Malignant Transformation of Squamous Cell Carcinoma in Mature Cystic Teratoma of the Ovary – A Systematic Review and Meta-Analysis of Data.

Background: Mature cystic teratomas (MCT) are the most common neoplasm of the ovary, occurring in 10-20% of women during their lifetimes. MCTs may rarely undergo malignant transformation, of which squamous cell carcinoma is the most common histopathology. This rare malignancy is poorly understood, therefore medical and surgical treatment has yet to be optimized to produce the best outcomes for patients diagnosed with squamous cell carcinoma in MCT (SCC-MCT). Objectives: To characterize the clinicopathologic features, surgical treatment, adjuvant treatment, and prognosis of SCC-MCT. Study Design: A systematic literature search was performed using MEDLINE through Ovid and Pubmed for relevant articles on malignant transformation of squamous cell carcinoma in mature cystic teratoma of the ovary. 155 studies were identified, yielding clinical information on 654 unique patients. Univariate and multivariate analyses were performed to assess factors influencing overall survival. Disease-free survival and overall survival of cases with follow-up were assessed by the Kaplan-Meier life-table analysis. Survival rates were assessed with the log-rank test. Results: We found that SCC-MCT generally presented in postmenopausal patients with tumor sizes greater than 10 cm. Patients diagnosed with FIGO Stage I disease had better survival than later stage disease, and higher FIGO stage was independently associated with worse overall survival. Longer overall survival was associated with younger age at diagnosis, low pre-operative levels of SCC Ag and CA-125, and treatment with lymphadenectomy. Chemotherapy or radiotherapy were not associated with improved survival. Conclusions: The prognosis of SCC-MCT is dependent on a variety of factors including age, serum tumor marker levels, and surgical treatment. Prognosis regardless of adjuvant treatment modality chosen for late-stage malignancy is generally poor. Future research focusing on collecting patient outcome data from international centers is needed to better guide treatment choices.