Adjuvant Capecitabine Following Concurrent Chemoradiotherapy in Locoregionally Advanced Nasopharyngeal Carcinoma A Randomized Clinical Trial

IMPORTANCE Induction or adjuvant chemotherapy with concurrent chemoradiotherapy (CCRT) are first-line treatment options for treatment of locoregionally advanced nasopharyngeal carcinoma (LA-NPC). Adjuvant platinum regimens are, however, poorly tolerated, highlighting the unmet need for an efficacious, tolerable adjuvant regimen. OBJECTIVE To investigate the efficacy and safety of adjuvant capecitabine with CCRT for the treatment of patients with LA-NPC. DESIGN, SETTING, AND PARTICIPANTS This open-label randomized clinical trial recruited patients from March 31, 2014, to July 27, 2018, at 3 institutions in China, with at least 3 years of follow-up. The data collection cutoff date was February 9, 2022. Eligibility included stage III-IVb nasopharyngeal carcinoma and at least 1 of the following: T3-4N2 or T1-4N3; plasma Epstein-Barr virus DNA titer higher than 20 000 copies/mL; primary gross tumor volume larger than 30.0 cm(3); fluorodeoxyglucose F 18 positron emission tomography/computed tomography maximum standard uptake value of the primary gross tumor volume larger than 10.0; or multiple nodal metastases and any larger than 4.0 cm. INTERVENTIONS Patients were randomly assigned 1:1 to receive either capecitabine (1000 mg/m(2) twice daily for 14 days every 3 weeks for 8 cycles) or observation following CCRT (100 mg/m(2) cisplatin every 3 weeks for 2 to 3 cycles, depending on duration of radiotherapy). MAIN OUTCOMES AND MEASURES Failure-free survival in the intention-to-treat cohort was assessed using Kaplan-Meier survival curves compared with the log-rank test. Unstratified Cox proportional hazards regression models were used to estimate hazard ratios, with corresponding 95% CIs based on the Wald test. RESULTS There were 180 patients enrolled (median [IQR] age, 47 [40-55] years; 143 [79.4%] men). Among 90 patients in the capecitabine group, 76 (84.4%) had at least 2 high-risk factors; among 90 patients in the control group, 80 (88.9%) had at least 2 high-risk factors. All patients completed CCRT, except 1 patient in the capecitabine group who received 1 cycle of cisplatin. Of the 90 patients in the capecitabine group, 85 (94.4%) received capecitabine, with 71 (78.9%) completing 8 cycles. With a median (IQR) follow-up of 58.0 (49.5-80.1) months, 18 events were recorded in the capecitabine group vs 31 events in the control group. Failure-free survival was improved with adjuvant capecitabine (3 years, 83.3% vs 72.2%; 5 years, 78.5% vs 65.9%; hazard ratio, 0.53 [95% CI, 0.30-0.94]; P =.03). The incidence of grade 3 treatment-related adverse events (TRAEs) was higher in the capecitabine group than in the control group (54 of 90 patients [60.0%] vs 46 of 90 patients [51.1%]). Treatment-related adverse events included xerostomia (17 [18.9%] vs 9 [10.0%] patients), mucositis (21 [23.3%] vs 15 [16.7%] patients), and anorexia (8 [8.9%] vs 4 [4.4%] patients). The incidence of grade 3 delayed treatment-related adverse events was comparable in both groups (9 of 83 [10.8%] vs 7 of 81 [8.6%] patients). CONCLUSIONS AND RELEVANCE In this randomized clinical trial, adjuvant capecitabine at the full dose following CCRT was well tolerated and improved failure-free survival among patients with LA-NPC and high-risk factors. Further investigations assessing optimal dose and duration are warranted.