Metastatic tumors to the oral and maxillofacial region: a retrospective study of 19 cases in West China and review of the Chinese and English literature.

PURPOSE The aim of this article was to obtain an overview of metastatic tumors to the oral and maxillofacial (OMF) region, especially the differences in the constituent ratios of primary cancers between the United States and China. PATIENTS AND METHODS Clinical findings of 19 cases encountered in West China Hospital of Stomatology were summarized and the English and Chinese literature were reviewed and analyzed. The main clinical features of OMF metastases were summarized, with an emphasis on primary cancers' constituents. RESULTS The lung, breast, kidney, liver, and prostate were the top 5 common primary sites of cancer. However, there was a significant difference in the primary cancers' constituents between United States and China (P < .001). The breast, kidney, prostate cancers, and melanoma of skin were more frequent primary cancers in United States than in China, whereas that of the lung, thyroid, liver, esophagus, and the stomach were more common in China than in United States. The proportions of the OMF metastatic lesions originating in the lung, kidney, liver, thyroid, and esophagus in all OMF metastatic tumors were higher than the corresponding primary cancers' prevalent proportions. CONCLUSIONS The frequency of developing OMF metastasis is not always consistent with primary cancers' prevalence, which suggests that different cancers have different potentiality to develop OMF metastasis. Cancers of the kidney, liver, lung, thyroid, and esophagus were more likely to spread to the OMF region. In general screening of primary cancer, it would be helpful to take into account the metastatic potentiality of different cancers and primary cancers' prevalence in different countries in the case of occult primary.