Selection and validation of chemotherapy beneficiaries among elderly nasopharyngeal carcinoma (NPC) patients treated with intensity-modulated radiation therapy (IMRT): a large real-world study.

PURPOSE: Using real-world evidence, this study aimed to identify elderly nasopharyngeal carcinoma (NPC) patients who would benefit from chemotherapy. METHODS AND MATERIALS: 1714 elderly NPC patients between April 2007 and December 2017 were identified. Recursive partitioning analysis (RPA) was used to generate risk-stratified outcomes. Prognostic factors were performed for individual comparisons of different risk groups to assess chemotherapy benefits. RESULTS: The median follow-up was 59.3 (0.39-170.09) months. Epstein Barr virus (EBV) DNA and T stage were included in the RPA-generated risk stratification, categorizing patients into a good-prognosis group (EBV DNA </= 4000 copies/mL & T1-2), and a poor-prognosis group (EBV DNA </= 4000 copies/mL & T3-4 and EBV DNA > 4000 copies/mL & any T). Overall survival (OS) was significantly higher in the good-prognosis group compared with the training set (HR = 0.309, 95% CI 0.184-0.517; P < 0.001), and validated in the testing set (HR = 0.276, 95% CI 0.113-0.670; P = 0.002). In the poor-prognosis group, a significantly improved OS for chemoradiotherapy (CRT) compared with RT alone was observed (HR = 0.70, 95% CI 0.55-0.88; P = 0.003). Patients who received induction chemotherapy (IC) + concurrent chemoradiotherapy (CCRT) and CCRT had a significantly improved OS compared with RT alone (IC + CCRT vs. RT alone: P = 0.002; CCRT vs. RT alone: P = 0.008) but not in the IC + RT group (P = 0.306). The 5-year OS for CRT versus RT-alone with ACE-27 scores of 0, 1 and 2 were 76.0% versus 70.0% (P = 0.014), 80.5% versus 68.2% (P = 0.150) and 58.5% versus 62.2% (P = 0.490), respectively; for those aged 60-64, 65-70 and >/= 70 years old they were 80.9% versus 75.9% (P = 0.068), 73.3% versus 63.4% (P = 0.270) and 64.8% versus 67.1% (P = 0.820), respectively. CONCLUSIONS: For elderly NPC patients a simple screening cutoff for chemotherapy beneficiaries might be EBV DNA < 4000 copies/ml & T3-4 and EBV DNA >/= 4000 copies/ml & any T, but not for those > 70 years old and with an ACE-27 score > 1. IC + CCRT and CCRT were effective forms of chemotherapy.