Prognostic Evaluation of Nasopharyngeal Carcinoma with Bone-Only Metastasis after Therapy

PURPOSE: To evaluate the prognosis of nasopharyngeal carcinoma (NPC) patients who developed bone-only metastasis after primary treatment and the stratification of these patients into different risk groups based on independent prognostic factors. MATERIALS AND METHODS: Eighty NPC patients who developed bone-only metastasis after definitive radiotherapy from October 2005 to December 2010 were enrolled. All these patients received palliative treatment for bone metastasis, including chemotherapy and/or radiotherapy. Clinical features, treatment modality, and laboratory parameters were examined with univariate and multivariate analyses. RESULTS: The median follow-up time was 15.5 months (range, 2–67 months) for the whole cohort. The median overall metastatic survival (OMS) time and the 2-year estimate OMS rate were 26.5 months and 52%, respectively. Multivariate analysis indicated that patients with short metastases-free interval, multiple bone metastases sites, high serum lactic dehydrogenase levels, and treated with radiotherapy or chemotherapy alone had significantly worse outcomes. Patients were stratified into three different risk groups based on the number of adverse factors present. The OMS curves of the three groups were all significantly different (p<0.001). CONCLUSION: Severl prognostic factors were found to be associated with worse outcomes. According to the number of adverse factors present, bone-only metastasis patients can be stratified into three risk groups with significantly different prognoses. Such grouping may help in improving the design of clinical trials and in guiding individualized treatment for NPC patients with bone-only metastasis.