Randomized phase-III-trial of concurrent chemoradiation for locally advanced head and neck cancer comparing dose reduced radiotherapy with paclitaxel/cisplatin to standard radiotherapy with fluorouracil/cisplatin: The PacCis-trial

Background and purpose: This multicenter, phase 3 trial investigates whether the incorporation of concurrent paclitaxel and cisplatin together with a reduced total dose of radiotherapy is superior to standard fluorouracil-cisplatin based CRT. Materials and methods: Patients with SCCHN, stage III-IVB, were randomized to receive paclitaxel/cisplatin (PacCis)-CRT (arm A; paclitaxel 20 mg/m(2) on days 2, 5, 8, 11 and 25, 30, 33, 36; cisplatin 20 mg/m(2), days 1-4 and 29-32; RT to a total dose of 63.6 Gy) or fluorouracil/cisplatin (CisFU)-CRT (arm B; fluorouracil 600 mg/m(2); cisplatin 20 mg/m(2), days 1-5 and 29-33; RT: 70.6 Gy). Endpoint was 3-year-disease free survival (3y-DFS). Results: A total of 221 patients were enrolled between 2010 and 2015. With a median follow-up of 3.7 years, 3y-DFS in the CisFU arm and PacCis arm was 58.2% and 48.4%, respectively (HR 0.82, 95% CI 0.56-1.21, p = 0.52). The 3y-OS amounted to 64.6% in the CisFU arm, and to 59.2% in the PacCis arm (HR 0.82, 95% CI 0.54-1.24, p = 0.43). In the subgroup of p16-positive oropharyngeal carcinomas, 3yDFS and 3y-OS was 84.6% vs 83.9% (p = 0.653), and 92.3% vs. 83.5% (p = 0.76) in arm A and B, respectively. Grade 3-4 hematological toxicities were significantly reduced in arm A (anemia, p = 0.01; leukocytopenia, p = 0.003), whereas grade 3 infections were reduced in arm B (p = 0.01). Conclusion: Paclitaxel/cisplatin-CRT with a reduced RT-dose is not superior to standard fluorouracil/cis platin-CRT. Subgroup analyses indicate that a reduced radiation dose seems to be sufficient for p16+ oropharyngeal cancer or non-smokers. (C) 2020 Elsevier B.V. All rights reserved.