Neoadjuvant Immunochemotherapy and Postoperative Adjuvant Immunotherapy for Head and Neck Squamous Cell Carcinoma Invading the Skull Base

Tislelizumab Combined With Chemotherapy for Neoadjuvant Immunochemotherapy and Postoperative Adjuvant Therapy for Head and Neck Squamous Cell Carcinoma Invading the Skull Base: A Prospective, Single-arm, Phase II Clinical Study

This prospective, single-arm, Phase II clinical trial aims to evaluate the efficacy and safety of tislelizumab combined with chemotherapy as neoadjuvant therapy and postoperative adjuvant immunotherapy in patients with skull base-invading head and neck squamous cell carcinoma. The primary objectives are to address the following questions:

• What are the objective response rate and pathological response of tislelizumab combined with chemotherapy as neoadjuvant therapy in patients with skull base-invading head and neck squamous cell carcinoma?
• Can neoadjuvant therapy convert unresectable skull base-invading head and neck squamous cell carcinoma into a resectable condition?
• Can adjuvant immunotherapy after neoadjuvant therapy prolong patients' recurrence-free survival and overall survival? The researchers will administer neoadjuvant therapy (tislelizumab combined with chemotherapy) and adjuvant immunotherapy to patients with skull base-invading head and neck squamous cell carcinoma and assess the treatment's efficacy and safety.

Participants will:

• Receive neoadjuvant therapy every 3 weeks (tislelizumab 200mg on Day 1, nab-paclitaxel 260mg/m² on Day 1, cisplatin 75mg/m² on Days 1-3) for 3 cycles.
• Undergo surgical treatment within 3 weeks after completing neoadjuvant therapy.
• Receive (chemo)radiotherapy 4-6 weeks after surgery.
• Receive adjuvant immunotherapy (tislelizumab 200mg) every 3 weeks after (chemo)radiotherapy for 8 cycles.

Inclusion Criteria:

• Age 18 to 80 years, regardless of gender;
• Histologically confirmed squamous cell carcinoma (including gingiva, buccal mucosa, palate, oropharynx, maxillary sinus, or maxilla/mandible) with radiological evidence of skull base invasion;
• Measurable tumor lesions (meeting RECIST v1.1 criteria);
• Treatment-naïve primary T4b-stage patients (N any, per AJCC 8th Edition, 2017);
• ECOG PS score: 0-1;
• Medically fit for surgery and chemotherapy, with no surgical contraindications;
• Women of childbearing potential (18-49 years) must have a negative pregnancy test within 7 days before treatment. Sexually active men and women must agree to use effective contraception during the trial and for 3 months after treatment cessation;
• Willing to provide written informed consent and comply with scheduled follow-ups, treatments, lab tests, and other study requirements.

Exclusion Criteria:

• Previous anti-tumor treatments including chemotherapy, radiotherapy, or immunotherapy; Refusal to sign informed consent;
• Patients who refuse the study treatment protocol; patients unable to complete treatment as planned; or patients unable to comply with regular follow-up due to psychological, social, familial or geographical reasons;
• Patients with known allergies to any study medications;
• Patients with poor systemic conditions unfit for treatment: as determined by routine tests (complete blood count, blood biochemistry, ECG, chest X-ray, etc.). Poor systemic conditions include: hemoglobin <60g/L, WBC <3.0×10⁹/L, platelets <80×10⁹/L, or serum creatinine >133μmol/L - such patients may be recommended for conservative treatment;
• Patients with autoimmune diseases requiring long-term immunosuppressive or corticosteroid therapy;
• Pregnant or lactating women (pregnancy testing should be considered for sexually active women of childbearing potential);
• Patients with current or previous malignancies (except adequately treated non-melanoma skin cancer, cervical carcinoma in situ, or papillary thyroid carcinoma);
• Participation in other clinical trials within 30 days prior to enrollment;
• Other conditions that may compromise patient safety or compliance as assessed by investigators, including: severe comorbidities (including psychiatric disorders), significantly abnormal laboratory results, or other high-risk familial/social factors.