Adding cetuximab to radiotherapy and cisplatin does not improve outcomes in patients with locoregionally advanced head and neck carcinoma, according to 10-year follow-up from a phase 3 trial.
The addition of cetuximab did not reduce local-regional failure or distant metastasis, and it did not improve progression-free or overall survival.
“With a median follow-up of over 10 years, this updated report confirms the addition of cetuximab to radiation/cisplatin did not improve any measured outcome in the entire cohort or when stratifying by p16 status,” said, of Moffitt Cancer Center in Tampa, Fla.
Dr. Caudellat the Multidisciplinary Head and Neck Cancer Symposium, sponsored by the American Society for Radiation Oncology.
Dr. Caudell noted that cisplatin plus radiotherapy or cetuximab plus radiotherapy have been shown to improve overall survival in patients with locoregionally advanced head and neck carcinoma. Researchers conducted this phase 3 trial, RTOG 0522 (), to determine if adding cetuximab to radiotherapy and cisplatin would improve progression-free survival.
The trial included 891 evaluable patients with stage T2 N2a-3 M0 or T3-4 N0-3 M0 disease. They were randomized to receive radiotherapy and cisplatin without cetuximab (n = 447) or with cetuximab (n = 444). Most patients were assigned to intensity-modulated radiotherapy (86.8% in the radiotherapy/cisplatin arm and 89.2% in the cetuximab arm) rather than 3-D conformal radiotherapy (13.2% and 10.8%, respectively).
Baseline characteristics were balanced between the treatment arms. The median age was 57 years (range, 31-79 years) in the radiotherapy/cisplatin arm and 58 years (range, 34-76 years) in the cetuximab arm. Nearly 90% of patients in both arms were men, and the oropharynx was the primary site of disease in about 70% of patients in both arms.
More patients were p16-positive (35.7% in the radiotherapy/cisplatin arm and 39.4% in the cetuximab arm) than were p16-negative (14.4% and 13.1%, respectively). However, p16 status was unknown for about half of patients in each arm.
At a median follow-up of 10.1 years, 452 patients were still alive.
The rate of local-regional failure was 28.5% in the radiotherapy/cisplatin arm and 34.8% in the cetuximab arm (hazard ratio, 1.21; P = .94). The rate of distant metastases was 15% and 11.8%, respectively (HR, 0.79; P = .10).
The 10-year progression-free survival rate was 43.6% in the radiotherapy/cisplatin arm and 40.2% in the cetuximab arm (HR, 1.06; P = .74). The 10-year overall survival rate was 49.9% and 50%, respectively (HR, 0.97; P = .36)
“As might be expected, patients who were p16-positive had a substantially improved progression-free survival as well as overall survival,” Dr. Caudell said. “Patients who had p16-negative oropharyngeal cancer or nonoropharyngeal cancer had equivalent progression-free survival and overall survival.”
However, the addition of cetuximab did not improve progression-free or overall survival in patients with p16-positive, p16-negative oropharyngeal, or nonoropharyngeal cancers.
“[These results] have proven conclusively that the addition of cetuximab to concurrent cisplatin and radiation therapy does not improve outcomes in stage III-IV head and neck cancer, regardless of the primary tumor site and p16 status,” said