Response adapted oncologic surgery following neoadjuvant immunotherapy and chemotherapy for resectable locally advanced oral cavity and oropharyngeal squamous cell carcinoma.

e18107 Background: Head and neck squamous cell carcinoma (SCC) is the seventh leading cause of cancer worldwide. For patients (pts) with oral cavity and oropharyngeal SCC (OSCC), surgery is the mainstay of treatment, but in locally advanced disease it is often associated with significant morbidity and compromise in quality of life. Historically, chemotherapy and immunotherapy (IC) have been utilized for patients with recurrent or metastatic disease in OSCC. We examined a group of pts with significantly advanced disease who elected treatment with neoadjuvant IC (NIC) with the goal of response adapted oncologic surgery as compared to anticipated pretreatment full surgical resection. Methods: In this retrospective case series, pts with newly diagnosed or recurrent, locally advanced (stage III,IVA, IVB), resectable OSCC (LAROSCC) were treated from 3/2023-4/2024. Pts received Carboplatin AUC 6, docetaxel 65mg/m2, and pembrolizumab 200mg IV every 3 weeks for up to 3 cycles followed by a planned surgical resection. Data regarding demographics, imaging findings, clinical findings, pathology, treatments, and outcomes were collected. Results: A total of 13 pts were included. Ten pts were male and 3 were female. The median age of pts was 65 years. Seven pts had recurrent disease, while 6 were new diagnoses. Eleven pts had disease in the oral cavity and 2 in the oropharynx. Ten pts had stage IVA disease, 1 with IVB, and 2 with III. Clinically, 12 (92%) pts noted improvement in their symptoms of disease following NIC. Of the 8 pts with interval imaging after NIC and prior to surgery, 2 (25%) demonstrated complete response, 4 (50%) with a partial response, 1(12.5%) with stable disease, and 1 (12.5%) with disease progression. Ten of the 11 (91%) pts who received surgery had enough clinical and radiographic response to significantly modify the surgical plan. The one patient who had progressed on NIC underwent the initial surgical plan. One patient had a complete clinical and radiographic response to NIC and elected to avoid surgery and remains disease free for over 6 months. One patient had clinical improvement and partial radiographic response, but has been hesitant to pursue surgery. Four pts (36%) had complete pathological response, 1 (9%) had microscopic pathologic disease, and 6 (55%) had residual disease. Most common symptoms of NIC were fatigue and nausea with 8 (62%) pts experiencing each. Only 1 patient required a dose reduction of docetaxel. With a median follow up time of 422 days, 10/13 (77%) pts remained disease-free and 13/13 (100%) are alive. Conclusions: NIC is feasible and well tolerated in pts with LAROSCC, allowing for response adapted oncologic surgery in the majority of pts with overall improved quality of life. Further studies are needed to evaluate the long-term impact of NIC and response adapted oncologic surgery in LAROSCC.