The impact of locoregional treatment on response to nivolumab in advanced platinum refractory head and neck cancer: The need trial

e18508 Background: Immunotherapy is the standard of care in the treatment of platinum-refractory recurrent/metastatic head and neck squamous cell carcinoma (R/M-HNSCC). Previous loco-regional treatment could have an impact on the immune system and response to Nivolumab. The aim of this study is to evaluate the efficacy and safety of Nivolumab in a real world population, identifying the impact of the clinic-pathological characteristics and previous treatment in prediction of early progression. Methods: This is a observational, multicenter retrospective/prospective study including patients (pts) with platinum refractory R/M HNSCC who received Nivolumab 240 mg every 2 weeks until disease progression or unacceptable toxicity, from October 2018 to October 2019. We analyzed treatment outcomes in term of early progression (within 3 months), clinical benefit, progression free survival (PFS) and overall survival (OS). To determine the influence on outcomes, the following variables were investigated: primary tumor sub-site, age, gender, ECOG, previous loco-regional treatment, previous systemic therapy, metastatic site. Results: Data from 61 pts were reviewed: 15 oral cavity, 14 oropharynx, 7 hyphofarynx, 19 larynx, 6 paranasal sinus. Median age was 66 years (29-82), 48 pts were men. Forty-nine pts (80%) had performance status (ECOG) ≥ 1 at baseline evaluation. Eleven pts (18%) had only loco-regional recurrence, while 50 pts (82%) had one or more metastatic site. 32 (52%) and 17 pts (28%) had smoking and alcohol abuse history, respectively. 44 pts (72%) received surgery followed by adjuvant radiant treatment at standard dose (28, 46%) or concomitant definitive radiotherapy (16, 26%) as upfront treatment with curative intent. With a median follow up of 4 months (range 1-11), early progression occurred in 39 pts during Nivolumab treatment (64%), while clinical benefit (stable disease and partial response) was achieved in 22 pts (36%). No G3-G4 toxicities occurred. Early progression to Nivolumab was significantly associated to previous loco-regional treatment both at univariate and multivariate analysis (p=0.003 and p= 0.04, respectively). Conclusions: Nivolumab in R/M HNSCC is effective and safe even though burdened with a high early progression rate. Loco-regional treatment, including wide neck dissection and high dose radiotherapy, may compromise the efficacy of Nivolumab, distorting the anatomy of the local lymphatic system and hindering the priming of immune response.