Evaluation of the prognostic significance of refinement and stratification of distant metastasis status in 1016 cases of nasopharyngeal carcinoma

Abstract

To investigate the prognostic factors for nasopharyngeal carcinoma (NPC) with different metastatic status, and to improve the NPC management by multi-level refinement and stratification of M1 stage distant metastases. Clinicopathological data of 1016 NPC patients with distant metastases were retrospectively reviewed. The M1 stage distant metastases were subdivided into synchronous or metachronous metastases, metastatic sites (lung, bone, liver), number of metastatic organs (solitary, multiple) and number of metastases (solitary, multiple) subgroups to analyze the prognosis and survival of the patients. The most frequently involved metastatic sites were bone (542, 53.3%), lung (420, 41.3%) and liver (302, 29.7%). There were solitary metastatic lesions in 164 patients (16.2%), synchronous metastases in 376 cases and metachronous metastases in 640 cases. The median overall survival of the whole group of 1016 NPC patients was 30.8 months since the time of diagnosis of metastasis. For the 376 patients in the synchronous metastasis group, the median survival was 23.3 months and the 1-, 3- and 5-year overall survival rates were 74.2%, 27.6% and 18.5%, respectively. For the 640 patients in the metachronous metastases group, the median survival was 36.7 months, and the 1-, 3- and 5-year overall survival rates were 88.1%, 49.6% and 28.6%, respectively, with a significant difference between the two groups (all P < 0.001). Cox multivariate analysis indicated that the number of metastatic lesions, different metastatic sites and N stage at initial diagnosis were independent prognostic factors for patients with metachronous metastases (P < 0.05). A theory of detailed multi-level metastasis (M1) stratification aiming at different distant metastasis status for nasopharyngeal carcinoma is proposed. To take appropriate individualized treatment scheme according to the prognosis and expected survival should be helpful to improving the diagnosis and treatment of nasopharyngeal cancer.