E1308: Phase II Trial of Induction Chemotherapy Followed by Reduced-Dose Radiation and Weekly Cetuximab in Patients With HPV-Associated Resectable Squamous Cell Carcinoma of the Oropharynx- ECOG-ACRIN Cancer Research Group.

Author(s): Marur S,  Li S,  Cmelak AJ,  Gillison ML,  Zhao WJ,  Ferris RL,  Westra WH,  Gilbert J,  Bauman JE,  Wagner LI,  Trevarthen DR,  Balkrishna J,  Murphy BA,  Agrawal N,  Colevas AD,  Chung CH,  Burtness B

Journal: J Clin Oncol

Date: 2017 Feb 10

Major Program(s) or Research Group(s): NCORP

PubMed ID: 28029303

PMC ID: PMC5455313

Abstract: Purpose Human papillomavirus (HPV)-associated oropharyngeal squamous cell carcinoma (OPSCC) is treatment-responsive. Definitive chemoradiation results in high cure rates but causes long-term toxicity and may represent overtreatment of some patients. This phase II trial evaluated whether complete clinical response (cCR) to induction chemotherapy (IC) could select patients with HPV-associated OPSCC for reduced radiation dose as a means of sparing late sequelae. Methods Patients with HPV16 and/or p16-positive, stage III-IV OPSCC received three cycles of IC with cisplatin, paclitaxel, and cetuximab. Patients with primary-site cCR to IC received intensity-modulated radiation therapy (IMRT) 54 Gy with weekly cetuximab; those with less than cCR to IC at the primary site or nodes received 69.3 Gy and cetuximab to those regions. The primary end point was 2-year progression-free survival. Results Of the 90 patients enrolled, 80 were evaluable. Their median age was 57 years (range, 35 to 73 years), with the majority having stage T1-3N0-N2b OPSCC and a history of ≤ 10 pack-years of cigarette smoking. Three cycles of IC were delivered to 77 of the 80 patients. Fifty-six patients (70%) achieved a primary-site cCR to IC and 51 patients continued to cetuximab with IMRT 54 Gy. After median follow-up of 35.4 months, 2-year progression-free survival and overall survival rates were 80% and 94%, respectively, for patients with primary-site cCR treated with 54 Gy of radiation (n = 51); 96% and 96%, respectively, for patients with < T4, < N2c, and ≤ 10 pack-year smoking history who were treated with ≤ 54 Gy of radiation (n = 27). At 12 months, significantly fewer patients treated with a radiation dose ≤ 54 Gy had difficulty swallowing solids (40% v 89%; P = .011) or had impaired nutrition (10% v 44%; P = .025). Conclusion For IC responders, reduced-dose IMRT with concurrent cetuximab is worthy of further study in favorable-risk patients with HPV-associated OPSCC. Radiation dose reduction resulted in significantly improved swallowing and nutritional status.