Analysis of clinical value of high-risk factors combined with stratification analysis in predicting clinical prognosis of N2-3M0 nasopharyngeal carcinoma patients

Objective To evaluate the clinical value of high-risk factors in combination with stratification method in predicting the clinical prognosis of patients diagnosed with N2-3M0 nasopharyngeal carcinoma (NPC). Methods A total of 226 N2-3M0 NPC patients who underwent IMRT from November 2013 to May 2015 were enrolled in this study. The relationship between tumor volume, cervical metastatic lymph node characteristics (necrosis and fusion) and T and N staging was analyzed. The high-risk factors that affected the survival were identified. The value of high-risk factors combined with stratification method in predicting the clinical prognosis was assessed. Results N3 staging, Vn≥47.15cm3 and lymph node fusion (LNF) were the high-risk factors for distant metastasis in patients with stage N2-3M0 NPC. All patients were classified into the low-risk, medium-risk, high-risk and extremely high-risk groups according to high-risk factors. For patients in the low-risk, medium-risk, high-risk and extremely high-risk groups, the 3-year overall survival rates were 84.2%, 76.7%, 58.7% and 36.4%(all P<0.001), 87.3%, 85.2%, 54.5% and 12.1% for the distant metastasis-free survival (DMFS) rates (all P<0.001), 76.8%, 74.3%, 49.2% and 12.1%for the progression-free survival (PFS) rates (all P<0.001), and 89.2%, 88.5%, 91.5% and 88.3% for the loco-regional recurrence-free survival (LRRFS) rates (P=0.914), respectively. The risk stratification method showed the best curve separation for DMFS compared to the Vn, N staging and LNF classification groups (all P<0.05). Conclusion High-risk factors in combination with stratification method has the highest clinical value in predicting the clinical prognosis of N2-3M0 NPC patients. Key words: Nasopharyngeal neoplasm; High-risk factors combined with stratification method; Clinical value