Therapeutic Effect of Chemotherapy Cycle in Nasopharyngeal Carcinoma (NPC) Patients Who Developed Bone-Only Metastasis

BACKGROUND: To compare the effects of chemotherapy dose escalation on survival and prognosis of nasopharyngeal carcinoma (NPC) patients who developed bone-only metastasis. MATERIAL/METHODS: Between October 2000 to March 2017, 58 NPC patients with initial bone-only metastasis were retrospectively analyzed. Patients who received <6 or ≥6 cycles of chemotherapy were matched and grouped using receiver operating characteristic curve (ROC) analysis. Overall survival (OS) was assessed using the Kaplan-Meier method, log-rank test, and Cox regression analysis. RESULTS: The median OS for the entire group was 24 months, while the 1-, 2-, and 3-year OS rates were 78.5%, 49.4%, and 26.8%, respectively. The median OS for patients who received <6 cycles of chemotherapy was 21 months, with 1-, 2-, and 3-year OS rates of 64.8%, 34.3%, and 17.2%, respectively. The median OS of patients who received ≥6 cycles of chemotherapy was 26 months, with 1-, 2-, and 3-year OS rates of 92.6%, 54.9%, and 30.9%, respectively. Multivariate analysis showed that the number of metastatic sites (≥3 vs. <3) and chemotherapy cycles (<6 vs. ≥6) were independent prognostic factors for OS. CONCLUSIONS: NPC patients who had less than 3 bone metastatic sites and who received ≥6 cycles of chemotherapy had better survival and prognosis.