Advanced Stage Mucinous Adenocarcinoma of the Ovary Is Both Rare and Highly Lethal A Gynecologic Oncology Group Study

BACKGROUND: Primary mucinous adenocarcinomas of the ovary are uncommon, and their biological behavior is uncertain. Retrospective studies have suggested that many mucinous carcinomas initially diagnosed as primary to the ovary have in fact metastasized from another site. A prospective randomized trial provided an opportunity to estimate the frequency of mucinous tumors, diagnostic reproducibility, and clinical outcomes. METHODS: A phase 3 trial enrolled 4000 women with stage III or IV ovarian carcinoma, treated by surgical staging and debulking, with randomization to one of five chemotherapeutic arms. Slides and pathology reports classified as primary mucinous carcinoma were reviewed independently by three pathologists. Cases were reclassified as primary or metastatic to the ovary according to two methods. Overall survival (OS) of reclassified groups was compared within the groups and with that of patients with serous carcinomas. RESULTS: Forty-four cases were classified as mucinous adenocarcinoma upon review. Using either method, only about one third were interpreted by the three reviewers as primary mucinous carcinomas. Reproducibility of interpretations among the reviewers was high, with unanimity of opinion in 30 (68%) cases. The median survival (MS) did not differ significantly between the groups interpreted as primary or metastatic, but the OS was significantly less than that for women with serous carcinoma (14 vs 42 months, P < 0.001). CONCLUSION: Advanced stage mucinous carcinoma of the ovary is very rare and is associated with poor OS. Many mucinous adenocarcinomas that are diagnosed as primary ovarian neoplasms ap pear to be metastatic to the ovary. Cancer 2011;117:554-62. (C) 2010 American Cancer Society