Results
A summary of the patients included in this study is depicted in Table 1. A total of 189 patients were identified, of which 132 (69.8%) were male, and 57 (30.2%) were female. The median age was 51 years (range, 25–85 years). The number of patients with history of smoking and alcohol consumption, hypertension, and diabetes were 34, 22, 41, and 9, respectively. The normal range of body mass index (BMI) was set at 20 kg/m2–26 kg/m2, and the number of patients with high, normal, and low BMI was 25, 150, and 14, respectively. For serologic factors, the number of patients with low hemoglobin (Hb<120 g/l), high NLR (≥6), and low ALP (<50 mmol/l) were 43, 52, and 9, respectively. According to rTNM staging system of the American Joint Committee on Cancer -AJCC/UICC,7 the tumors were staged as follows: rT1, 55; rT2, 42; rT3, 64; and rT4, 28. Forty-five patients (23.8 %) had lymph node metastases. The histological subtype in most patients was World Health Organization (WHO) type III (n =119; 63.0%), followed by the WHO type II (n =70; 37.0 %). Tumor necrosis was observed in 70 patients (37.0%).
T he overall 1-, 3-, and 5-year survival rates were 82.2%, 59.5%, and 43.6%, respectively, during a median follow-up of 24 months (range, 2-111 months) in all patients (Fig. 1). The 5-year overall survival (OS) of rT1, rT2, rT3, and rT4 were 42.5%,54.4%,44.1%,and 32.5%, respectively (Fig. 2). Sixty-nine patients had died, out of which 38 patients died of tumor progression at the locoregional site (33) or brain (5); two of lung metastasis, one of liver metastasis; 22 of severe internal carotid hemorrhage, two of temporal lobe necrosis, and four patients died of other diseases or accident. The tumors were relieved by physical examination and imaging examination in 89 cases (47.1%), and 31 patients (16.4 %) remained alive with disease.
P rognostic factors for recurrent NPC are shown in Table 2. In patients over 50 years of age (Fig. 3A), diabetes (Fig. 3B) and low BMI (<20 kg/m2, Fig. 3C) were associated with poor prognosis (P=0.039, P<0.001, P=0.011). Low hemoglobin (<120g/l, Fig. 3D) and increased NLR (≥6, Fig. 3E) also adversely affected outcomes. Patients with stages rT3 and rT4 had a 40.0% five-year cumulative survival rate, whereas patients with rT1 and rT2 had an improved survival rate of 50.3% (p=0.001, Fig. 3F). Lymph node metastasis (Fig. 3G ) and tumor necrosis (Fig. 3H) were associated with poor prognosis (p=0.029,P<0.001); however, sex, history of smoking and alcohol consumption, hypertension, low ALP (<50 mmol/l), number of sessions of radiotherapy, preoperative chemotherapy, pathological type, interval between recurrence and the last session of radiotherapy did not influence overall survival. Variables considered significant in the univariate analyses were entered in the Cox multivariate analyses (Table 3). A total of seven variables, including age, BMI, NLR, diabetes, T stage, N stage or tumor necrosis, were proven independent prognostic factors in the multivariate Cox regression model (Table 3). Moreover, based on the factors affecting OS, the predictive values of tumor recurrence was also analyzed by ROC, which revealed that tumor necrosis was the best predictor for OS. The area under the ROC curve for tumor necrosis was 0.347 (95% confidence interval [CI], 0.264 to 0.429; p <0.001) for OS. The prognostic values determined for the other factors are listed in Figure 4.