Cetuximab Treatment beyond Progression in Patients with Recurrent or Metastatic Head and Neck Squamous Cell Carcinoma: A Nationwide Population-Based Study (THNS-2021-08)

Background: Little is known regarding the association of cetuximab treatment beyond progression (TBP) with survival among patients with recurrent or metastatic head and neck squamous cell carcinoma (R/M HNSCC). Although immune checkpoint inhibitors (ICIs) are now considered as first-line treatment, not all patients are suitable for ICIs. Objective: We conducted a multicenter, retrospective study to evaluate the role of cetuximab TBP in patients with R/M HNSCC after failure of first-line cetuximab-containing chemotherapy. Patients and Methods: Patients with R/M HNSCC who had tumor progression after first-line cetuximab-containing chemotherapy were included into our study. Oncologic outcomes were estimated including time to cetuximab treatment discontinuation (TTD), progression-free survival 2 (PFS2), overall survival (OS), overall response rate (ORR), and disease control rate (DCR). Multivariate cox regression analysis with survival were conducted. Subgroup analysis with P16 and programmed death ligand 1 expression were performed. Results: A total of 498 patients were eligible with 259 patients in the TBP group and 239 patients in the non-TBP group. The most common first-line chemotherapy was the EXTREME regimen in both groups. As for second-line treatment, the most common regimen were TPEx in the TBP group and taxane-based chemotherapy in the non-TBP group. Median TTD was 8.7 months in TBP and 5.5 months in non-TBP (p < 0.001). In terms of survival, median OS1 was significant longer in the TBP group than in the non-TBP group [14.1 months versus 10.9 months (p = 0.016)]. Multivariate analysis demonstrated cetuximab TBP was a factor independently associated with OS. Conclusions: Our retrospective study suggests cetuximab TBP to be effective and to provide better survival for patients with R/M HNSCC after failure of first-line cetuximab-containing chemotherapy. Further prospective studies are warranted to validate the role of cetuximab TBP in R/M HNSCC.