Background: The aim of this study was to analyze the prognostic factors for nasopharyngeal carcinoma (NPC) patients with distant metastasis after intensity-modulated radiotherapy (IMRT), and to provide a further basis for clinical treatment options.
Methods: One hundred and fifty-two NPC patients with distant metastasis after IMRT from January 2006 to December 2017 were included in this study and reviewed for analysis. The patients were followed up for a median time of 43 months. The survival rate was calculated and compared using the Kaplan-Meier method and log-rank tests, respectively. The Cox risk ratio model was used for univariate and multivariate analyses.
Results: Among all patients, the median interval from treatment completion to distant metastasis was 11.3 months. The median post-metastasis survival was 14 months, and the 1-, 2-, and 3-year survival rates were 60.4%, 40.2%, and 27.6%, respectively. Through univariate analysis, we found that overall survival was related to lymph node (N) staging at diagnosis, whether induction chemotherapy was utilized, the interval time from initial radiotherapy completion to distant metastasis, with/without liver metastasis, and whether chemotherapy or palliative radiotherapy were utilized after metastasis discovery. Cox regression results showed that liver metastasis, multi-organ metastasis, chemotherapy after metastasis, and the time from radiotherapy completion to distant metastasis were independent prognostic factors for patient survival.
Conclusions: The prognosis of NPC patients with distant metastasis after IMRT was related to the time from radiotherapy completion to distant metastasis, liver and multi-organ metastasis, and whether adjuvant chemotherapy was administered. Both adequate adjuvant chemotherapy and palliative radiotherapy could potentially prolong the patients' survival.
Keywords: Nasopharyngeal carcinoma (NPC); distant metastasis; intensity-modulated radiotherapy (IMRT); survival analysis.