X versus XELOX versus PF in definitive concurrent chemoradiotherapy (DCRT) for local-advanced squamous esophageal cancer (ESCC): 2021 update from a multicenter, open-label, randomized III trial, CRTCOESC trial

4531 Background: PF (5-fluorouracil plus cisplatin) is the standard regimen for local advanced ESCC with DCRT. CRTCOESC aims to evaluate the effect and safety of X (capecitabine) regimen versus XELOX (capecitabine plus oxaliplatin) and PF in Chinese local advanced ESCC with DCRT by randomized, open-label, multicenter designed. Methods: Patients with ESCC (T2-4N0-2M0) were randomized to 3 groups as X (capecitabine 625mg/m2, bid d1-5, 6 weeks), XELOX (oxaliplatin: 65mg/m2, d1, 8, 22, 29; capecitabine: 625mg/m2, bid d1-5; 6 weeks), or PF (cisplatin: 75mg/m2 d1, 29, 5-Fu: 750mg/m2 CIV24h d1-4, d29-32), Intensity Modulated Radiation Therapy (IMRT) was delivered by 50Gy/2Gy currently. In addition, quadratic randomize were done within all groups to decide whether 2 cycles chemotherapy adding or not after DCRT. 2-year OS and Grade 3-5 AEs were the primary endpoints, 2-year PFS and short-term efficacy (STE) as rates of CR and ORR (CR+PR+SD) (confirmed by gastroscopy biopsy at 16 weeks) were the secondary endpoints. Results: 244 pts successfully were accrued from 13 centers during 2014.10-2020.1. 209 pts were finished DCRT and 193 were evaluated STE at 16 weeks. 192 and 147 pts were followed up for 1- and 2- years respectively. There were no differences between 3 groups on patients’ baseline characters including age, gender, ECGO score, clinical stage, pathology grade and smoking. In X, XELOX and PF groups, the 2-year OS were 63.8% (30/46), 61.5% (32/52) and 62.5% (30/49) ( P = 0.973), the median OS were 39.7 (6.567), 40 (5.195) and 34 (5.736) (months, P = 0.703); the incidences of AEs (grade 3-5) were 26.5% (18/68), 33.8% (25/74) and 49.3% (33/67) ( P = 0.0193); the 2-year PFS were 54.3% (25/46), 53.8% (28/52) and 51% (25/49) ( P = 0.939), the median PFS were 29.06 (6.124), 17.4 (8.745) and 24.833 (6.777) (months, P = 0.811); the CR rate were 43.8% (28/64), 41.4% (29/70), and 42.4% (25/59) ( P = 0.964), and the ORR were 85.6%, 88.6%, and 96.6% ( P = 0.119), respectively. There were no differences on OS, PFS and rates of CR and ORR between 3 groups but the incidence of AEs in X group was the lowest significantly. Subgroup analysis results shown adding 2 cycles chemotherapy after CRT had both OS and PFS advantages but lacked statistically significance. Conclusions: Compared with PF, DCRT with X or XELOX shown lower incidence of AEs and similar OS, PFS and STE. X regimen carried out the lowest AEs incidence. Adding 2 cycles chemotherapy after DCRT seemly had advantages on OS and PFS. Clinical trial information: NCT02025036 .