Our study described the incidence proportion and prognostic role of liver metastasis in newly diagnosed ovarian cancer patients and the analyses also stratified by histologic subtypes. We observed that ovarian carcinosarcomas has the highest incidence of liver metastasis. Notably, the median cancer-specific survival significantly varied by different subtypes, ranging from 5 months in mucinous type to 34 months in nonepithelial ovarian cancer patients with liver metastasis. To the best of our knowledge, this is the first study to report population-based incidence proportions and survival outcomes stratified by histological subtypes in ovarian cancer patients with liver metastases on initial diagnosis.
In previously published study, Giovanni D. Aletti et al. evaluated on the incidence proportion of ovarian cancer patients who were in FIGO stage IV at the time of diagnosed from 1994 through 2003 at the Mayo clinic. They identified stage IV disease among 19% patients with ovarian cancer (all stages at diagnosis). The liver was the second most common metastasis site, accounting for 21% of the primary metastasis diagnosis and treatment. This study emphasized that stage IV is a heterogeneous ovarian cancer, and the metastases anatomic location at diagnosis appears useful as an excellent predictor for prognosis. Patients with liver metastases most frequently had recurrence and poor prognosis. As opposed to in this study, the tumor histological subtype was not available, and incidence was not reported. Our study focused on the cumulative incidence proportions of liver metastasis among patients with the different ovarian cancer subtypes. We found that the total incidence of ovarian cancer with liver metastasis was 6.91%, and carcinosarcoma of the ovary was the most common subtype among those with liver metastasis, accounting for 14.1%. Ovarian carcinosarcomas, also called malignant mixed Mullerian tumors (MMMTs), have been reported as a rare tumor with a poor prognosis[12, 13]. However, the liver metastasis of ovarian carcinosarcomas has not been described in previous published studies.
In a study of 1481 patients diagnosed with stage IV ovarian cancer, 32.5% had a single liver metastasis, and the median survival time was 30 months. Another study in Japan, including 107 ovarian cancer patients, showed that the median ovarian survival was 9 months. All the academic center–based retrospective studies suggested that ovarian cancer with liver metastasis predicted poor survival, and the median cancer-specific survival fluctuated between 8 and 40 months. We found that the median cancer-specific survival was obviously decreased in ovarian cancer patients with liver metastasis compared with those without metastasis (18 months vs. 77 months, P < 0.001). When compared with distant visceral metastasis, there was no significant difference (18 months vs. 19 months, P < 0.81). These data suggested that distant metastasis was the main cause of poor prognosis and that liver metastasis was still the most important factor. In addition, we also found that the median survival for ovarian cancer patients with liver metastases varied significantly by histological subtype, with mucinous ovarian cancer being associated with the worst survival (median cancer-specific survival, 4 months). Serous ovarian cancer patients had the longest survival (median cancer-specific survival, 21 months).
Due to the low level and small-scale studies, the professional guidelines did not recommend the treatment of liver metastasis of ovarian cancer[15–17]. Several studies have suggested that surgery for liver resection for ovarian cancer with liver metastasis predicts a favorable prognosis compared to women with unresectable liver disease[18–20]. Our data also showed the same results. Therefore, liver surgery, especially R0 surgery, should be recommended for ovarian cancer with liver metastasis. Certainly, new therapeutic approaches, including radiofrequency ablation (RFA) and transcatheter arterial chemoembolization (TACE), all have appeared to have therapeutic effects in small sporadic samples or case studies[21, 22].
Our study should be considered in the context of its limitations. First, 25293 cases of ovarian cancer from SEER database were included in this study, although the SEER data covers approximately 30% of the United States population, the selection bias was inevitable in the incidence proportions analysis. Second, the SEER database did not provide information about ovarian cancer recurrence, so we only described liver metastases at initial diagnosis. Third, information from SEER database did not provide chemotherapy data, so the chemotherapy-related prognostic analyses for liver metastasis were not conducted.