Adjuvant capecitabine in locoregionally advanced nasopharyngeal carcinoma: A multicenter randomized controlled phase III trial

6005 Background: We conducted a multicenter, randomized controlled phase III clinical trial (NCT02143388) to investigate the efficacy and toxicity of adjuvant capecitabine (AC) in addition to concurrent cisplatin and radiotherapy (CCRT) compared to CCRT alone in high-risk locoregionally advanced nasopharyngeal carcinoma (LANPC) patients. Methods: Eligibility criteria included AJCC/UICC 7th ed TNM stage III-IVb and one of the following features: T3-4N2 or T1-4N3 or pre-treatment plasma EBV DNA concentration of >20,000 copy/ml or gross primary tumor volume (GTVnx) of >30 cm3 or a maximum standard uptake value (SUVmax) of >10.0 by 18FDG PET-CT within the primary tumor or multiple neck node metastases, with any larger than 4 cm. All patients were randomly assigned in a 1:1 ratio to receive CCRT (3-weekly cisplatin at 100 mg/m2 for 2-3 cycles) followed by AC (1000 mg/m2 bi-daily for 14 days every 21-day cycle for 8 cycles), or CCRT alone. The prescribed radiation doses were 68-72 Gy/30-32 fractions to the PTVnx, 60-68 Gy/30-32 fractions to PTVnd, 60-64Gy/30-32 fractions to PTVhigh-risk, 54-58Gy/30-32 fractions to PTVlow-risk. Primary end point was failure-free survival (FFS). Results: Between Mar 2014 to Jul 2018, 180 patients were recruited (90 patients in CCRT+AC arm and 90 in CCRT alone arm). All patients completed RT and ≥2 cycles of concurrent cisplatin in both treatment arms (cumulative dose intensities for cisplatin were 200 mg/m2 in both arms). 85 (94.4%) patients went on to receive AC, with 71 (78.9%) patients completing 8 cycles; 19 (22.4%) patients had dose reduction of AC. With a median follow-up of 44.8 mo, the 3-y FFS was significantly superior in the CCRT+AC arm than the CCRT arm for the intention-to-treat cohort (87.7% vs 73.3%; HR: 0.52 [95% CI: 0.29-0.77], P = 0.037). 3-year overall, distant metastasis-free and locoregional relapse-free survival were 92.6% vs 88.9% (HR [95% CI]: 0.66 [0.28-1.59]), 88.8% vs. 81.1% (HR: 0.67 [0.33-1.33]) and 91.5% vs 80.0% (HR: 0.50 [0.25-1.00]), respectively. Incidences of G3-4 acute toxicities were 57.8% (52 of 90) in CCRT+AC arm and 51.1% (46 of 90) in CCRT alone arm, with a higher incidence of hand foot syndrome (3.5% vs 0%), xerostomia (11.1% vs 3.3%), mucositis (23.3% vs 16.7%), and anemia (5.6% vs 2.2%) in the CCRT+AC arm. G3-4 late toxicities occurred in 13.3% (12 of 90) and 9.0% (8 of 89), respectively. Conclusions: The addition of capecitabine to CCRT conferred a superior disease control than CCRT alone in high-risk LANPC. Survivals in ITT and PP set. Clinical trial information: NCT02143388. [Table: see text]