Platinum resistance and sensitivity in recurrent/metastatic head and neck squamous cell carcinoma.

OBJECTIVE:For patients with recurrent/metastatic head and neck squamous cell carcinoma (R/MHNSCC), platinum-free interval (PFI)-based differences in the effectiveness of rechallenge with platinum-based chemotherapy (PBCT) remain unknown. We aimed to evaluate the difference in platinum sensitivity based on PFI in R/MHNSCC. METHODS:We retrospectively examined 80 patients with R/MHNSCC who underwent PBCT between 2001 and 2020. Treatment efficacy was compared between patients with prior PBCT for treatment of recurrence/metastasis or concurrent chemoradiotherapy during radical treatment (rechallenge group) and those without (control group). Patients with prior PBCT (rechallenge group) were stratified by PFI. PFI was defined as the period from the last dosing date with the previous platinum agent to rechallenge with PBCT. RESULTS:Of 80 patients, 55 had been with prior PBCT (rechallenge group) and 25 had been without prior PBCT (control group). The rechallenge group was divided into three groups: PFI <6 months (10), PFI 6-11 months (17), and PFI ≥12 months (28). The PFI <6-month group had shorter overall survival (p=0.047, the log-rank test) and lower disease control rate (p=0.02, Fisher's exact test) than the control group. The PFI 6-11- and ≥12-month group outcomes did not significantly differ from those of the control group. CONCLUSIONS:Patients with PFI <6 months tend to have a poorer prognosis after rechallenge with PBCT than patients without prior PBCT, suggesting that PFI 6 months may be considered as a threshold of platinum resistance and rechallenge with PBCT may be a valid option in PFI ≥6 months.