Effect of tumor burden and growth rate on treatment outcomes of nivolumab in head and neck cancer

Background Nivolumab improves overall survival (OS) in patients with platinum-refractory recurrent and metastatic head and neck squamous cell carcinoma (R/M HNSCC). In one study, however, Kaplan-Meier OS and progression-free survival (PFS) curves for the nivolumab and cytotoxic agent arms crossed at 3-6 months, suggesting that patients with initial resistance to immunotherapy might have better outcomes with cytotoxic treatment. Here, we explored the conditions and candidates which are predictive of nivolumab outcomes in R/M HNSCC. Methods We retrospectively reviewed the clinical records of 27 consecutive R/M HNSCC patients treated with nivolumab from 2014 to 2018. Tumor size was evaluated by RECIST ver.1.1. Tumor growth rate (Gr) was defined as 3log(D-0/D-pre)/t, whereD(0)andD(pre)are the sum of the diameters of the target lesions (SumTLs) at baseline and pre-baseline, andtis time, with 1tdefined as 4 weeks. Results Twenty-five patients were enrolled. Survival was significantly worse in patients with disease progression within 3 months. Outcomes appeared poorer in patients with higher pre-treatment Gr and bigger SumTLs at baseline. We therefore explored the association between prognosis, Gr and SumTLs. Recursive partitioning analysis showed that the characteristics of patients with disease progression after 3 months were Gr < 0.76 and SumTLs < 31.0 mm. Further, Gr < 0.76 and SumTLs < 31.0 mm was associated with significantly longer PFS (p = 0.01) and OS (p < 0.01). Conclusions These results suggest that Gr and SumTLs at baseline are significantly associated with OS and PFS in R/M HNSCC patients treated with nivolumab.