Post-treatment prognostic score model establishment and stratified therapy for newly diagnosed metastatic nasopharyngeal carcinoma

Abstract

Objective To establish a post-treatment prognostic score model for newly diagnosed metastatic nasopharyngeal carcinoma, and to investigate the feasibility of stratified therapy. Methods A total of 263 eligible patients with newly diagnosed metastatic nasopharyngeal carcinoma from 2002 to 2010 were enrolled as subjects. The primary tumor was treated with conventional radiotherapy, three-dimensional conformal radiotherapy, or intensity-modulated radiotherapy, and radiation areas included nasopharyngeal tumor and cervical lymphatic drainage region. The metastatic bone tumor was mainly treated with conventional external radiotherapy, while the metastatic liver or lung tumor was mainly treated with surgical resection, radiotherapy, or radiofrequency ablation. The first-line therapy for most of patients was cisplatin-based combination chemotherapy. Factors including the general characteristics, tumor status, and therapy for patients were involved in multivariate analysis, and a prognostic model was established based on the n value(HR = en)of the prognostic factors. Results The factors influencing the overall survival(OS)in patients were a Karnofsky performance score(KPS)not higher than 70(P = 0. 00), multiple organ metastases(P = 0. 00), combination with liver metastasis(P= 0. 00), a number of metastases not less than 2(P=0. 00), a level of lactate dehydrogenase(LDH)higher than 245 IU/L(P = 0. 00), a number of chemotherapy cycles ranging between 1 and 3(P= 0. 00), a poor response for metastatic tumor(stable disease or progressive disease)(P = 0. 00), and primary tumor not treated with radiotherapy(P=0. 01). Based on the prognostic score, patients were divided into low-risk group(0-1. 5 points), intermediate-risk group(2. 0-6. 5 points), and high-risk group(≥7. 0 points), and the 5-year OS rates in the three groups were 59. 0%, 25. 1%, and 0%, respectively. Conclusions The prognostic score model based on the KPS, serum level of LDH, multiple organ metastases, combination with liver metastasis, and number of metastases can effectively predict the survival in patients. Active treatment including at least 4 chemotherapy cycles and radiotherapy for primary tumor can prolong the survival time of patients in the low-and intermediate-risk groups. However, patients in the high-risk group were mainly treated with palliative radiotherapy due to no improvement in the survival by radiotherapy for primary tumor. Key words: Nasopharyngeal neolasms, metastasis/radiotherapy; Nasopharyngeal neolasms, metastasis/chemotherapy; Prognostic-score model