Optimizing the Cumulative Cisplatin Dose for Concurrent Chemoradiotherapy Beneficiaries Among Elderly Nasopharyngeal Carcinoma Patients: A Real World Study

Abstract

Objective This study aimed to find a safe and effective cumulative cisplatin dose (CCD) for concurrent chemoradiotherapy (CCRT) beneficiaries among elderly nasopharyngeal carcinoma (NPC) patients. Materials and methods A total of 765 elderly (≥ 60 years old) NPC patients treated with cisplatin-based CCRT and IMRT-alone from 2007 to 2018 were included in this study. RPA-generated risk stratification was used to identify CCRT beneficiaries. CCDs were divided into CCD = 0, 0 < CCD ≤ 80, 80 < CCD ≤ 160 and 160 < CCD ≤ 300 mg/m2 and their OS and nephrotoxicity compared. Results Pre-treatment plasma EBV DNA and clinical Stage were incorporated into the RPA model to perform risk stratification. All patients were classified into either a high-risk group (n = 158, Stage IV), an intermediate-risk group (n = 193, EBV DNA > 2000 copy/mL & Stage I, II, III) or a low-risk group (n = 414, EBV DNA ≤ 2000 copy/mL & Stage I, II, III). The 5-yearOS of CCRT vs. IMRT alone in the high-, intermediate- and low-risk groups after balancing covariate bias were 60.1% vs 46.6% (p = 0.02), 77.8% vs 64.6% (p = 0.03) and 86.2% vs 85.0% (p = 0.81), respectively. The 5-year OS of patients receiving CCD = 0, 0 < CCD ≤ 80, 80 < CCD ≤ 160 and 160 < CCD ≤ 300 mg/m2 after balancing covariate bias in the high-risk group were 45.2%, 48.9%, 73.4% and 58.3% (p = 0.029), in the intermediate-risk group they were 64.6%, 65.2%, 76.8% and 83.6% (p = 0.038), and in the low-risk group they were 85.0%, 68.1%, 84.8% and 94.0% (p = 0.029), respectively. In the low-risk group, the 5-year OS of Stage III patients receiving CCD = 0, 0 < CCD ≤ 80, 80 < CCD ≤ 160 and 160 < CCD ≤ 300 mg/m2 were 83.5%, 76.9%, 85.5% and 95.5% (p = 0.044), respectively. No Grade 3–4 nephrotoxicity occurred. Conclusions In our study, Stage I, II & EBV DNA > 2000copy/ml and Stage III, IV elderly NPC patients may be CCRT beneficiaries. 80 < CCD ≤ 300 mg/m2 is recommended for the high-risk (Stage IV) group, and 160 < CCD ≤ 300 mg/m2 for the intermediate-risk (Stage I, II, III & EBV DNA > 2000copy/ml) and low-risk (Stage III&EBV DNA ≤ 2000 copy/ml) groups. No Grade 3–4 nephrotoxicity occurred in any of the CCD groups.