Prognostic analysis of 68 patients with initially diagnosed bone-only metastatic nasopharyngeal carcinoma

Objective: To analyze the prognostic factors in patients with initially diagnosed bone-only metastatic nasopharyngeal carcinoma (NPC). Methods: We collected the data of 68 patients with initially diagnosed bone-only metastatic NPC admitted to The Affiliated Tumor Hospital of Shantou University Medical College from 1997 to 2015. Forty-nine patients received chemoradiotherapy. The Kaplan-Meier method was used to calculate the overall survival rate; the log-rank test was used for univariate prognostic analysis; the Cox model was used for multivariate prognostic analysis. Results: The median follow-up was 95.3 months. The 1-, 2-, 3-, and 5-year overall survival (0S) rates were 53%, 38%, 21%, and 15%, respectively. The median 0S time was 13.4 months. The univariate prognostic analysis showed that spinal metastases, the number of bone metastases, lactic dehydrogenase level before treatment, the radiotherapy technology and dose for primary tumor, and the short-term outcome of primary tumor were associated with 0S (P = 0.02, 0.01, 0.00, 0.02, 0.02, 0.01). The multivariate prognostic analysis showed that ≤ 3 bone metastases, dose to primary tumor > 65 Gy, and intensity-modulated radiotherapy (IMRT) were favorable prognostic factors for 0S (P = 0.03, 0.02, 0.04). Conclusions: For patients with initially diagnosed bone-only metastatic NPC, active treatment (IMRT, dose to primary tumor > 65 Gy) should be considered for those with ≤ 3 bone metastases to achieve a complete response of primary tumor. (authors)