Overview

This is a single-center, open-label, randomized, controlled, exploratory clinical trial designed to evaluate the efficacy and safety of de-escalated surgery compared with standard surgery in patients with resectable locally advanced head and neck squamous cell carcinoma (LA-HNSCC) who achieved a partial response (PR) or complete response (CR) after neoadjuvant immunochemotherapy. Eligible patients will be randomly assigned in a 1:1 ratio to either the de-escalated surgery group (experimental) or the standard surgery group (control). The de-escalated surgery group will undergo limited tumor resection and selective neck dissection based on clinical and imaging response, while preserving important anatomical structures and functions when feasible. The control group will receive standard surgical treatment following NCCN guidelines. All patients will be evaluated using RECIST 1.1 criteria for radiological response and will undergo enhanced CT or MRI at baseline, before the second cycle of neoadjuvant therapy, within one week before surgery, 30 days after surgery, and every 3 months thereafter until 2 years post-surgery, disease recurrence, death, or study completion. The study aims to assess whether de-escalated surgery can achieve similar oncologic outcomes while improving postoperative function and quality of life. The primary endpoints are disease-free survival (DFS), health-related quality of life (HRQoL), and 3- and 5-year overall survival rates (OS rate). A total of 60 patients will be enrolled over a 3-year period, with 30 in each group.

Eligibility

Inclusion Criteria:

• Patients diagnosed with stage III-IVa head and neck squamous cell carcinoma (HNSCC) according to the AJCC 8th edition TNM staging system, who have achieved a partial response (PR) or complete response (CR) after receiving neoadjuvant immunochemotherapy consisting of a PD-1 inhibitor in combination with nab-paclitaxel and carboplatin/cisplatin.
• No prior history of other malignant tumors.
• Aged between 18 and 75 years.
• Normal baseline (preoperative) clinical and laboratory findings:
• 1.Absolute neutrophil count (ANC) ≥ 1.5 × 10⁹/L without the use of granulocyte colony-stimulating factor (G-CSF) within the previous 14 days
• 2.Platelet count ≥ 100 × 10⁹/L without blood transfusion within the previous 14 days
• 3.Hemoglobin \> 9 g/dL without blood transfusion or erythropoietin use within the previous 14 days
• 4.Total bilirubin ≤ 1.5 × upper limit of normal (ULN)
• 5\. Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) ≤ 2.5 × ULN
• 6\. Serum creatinine ≤ 1.5 × ULN and creatinine clearance (calculated using the Cockcroft-Gault formula) ≥ 60 mL/min
• 7\. Adequate coagulation function, defined as international normalized ratio (INR) or prothrombin time (PT) ≤ 1.5 × ULN
• 8\. Normal thyroid function, defined as thyroid-stimulating hormone (TSH) within the normal range. Subjects with TSH outside the normal range may be included if total T3 (or FT3) and FT4 are within normal limits
• 9\. Normal myocardial enzyme profile (minor laboratory abnormalities judged by the investigator to be clinically insignificant are acceptable)
• Female subjects of childbearing potential must have a negative urine or serum pregnancy test within 3 days prior to the first dose of study treatment (Cycle 1, Day 1). If the urine test is indeterminate, a serum test must be performed. Non-childbearing females are defined as those who have been postmenopausal for at least one year or have undergone surgical sterilization or hysterectomy.
• All subjects (male or female) with reproductive potential must agree to use highly effective contraception (annual failure rate \<1%) during treatment and for at least 120 days after the last dose of study drug, or 180 days after the last dose of chemotherapy.
• Adverse events related to neoadjuvant therapy (e.g., bone marrow suppression, thyroiditis, hypothyroidism, hepatitis, nephritis, myocarditis, myositis, etc.) must have been adequately controlled and resolved to grade 0-2 before surgery. Patients assessed by anesthesiology as fit for general anesthesia may be included.
• Patients with pre-existing comorbidities prior to neoadjuvant therapy may also be enrolled if evaluated by anesthesiology and deemed able to tolerate general anesthesia.
• Signed written informed consent.

Exclusion Criteria:

• Diagnosis of another malignant tumor, or the primary lesion at the time of neoadjuvant therapy was not oral cancer.
• Active autoimmune disease requiring systemic treatment (e.g., disease-modifying agents, corticosteroids, or immunosuppressants) within 2 years prior to treatment. Replacement therapy (e.g., thyroxine, insulin, or physiological corticosteroids for adrenal or pituitary insufficiency) is not considered systemic treatment.
• History of allogeneic organ transplantation (except corneal transplantation) or allogeneic hematopoietic stem cell transplantation.
• Known history of human immunodeficiency virus (HIV) infection (i.e., positive HIV-1/2 antibody).
• Untreated active hepatitis B infection, defined as HBsAg positivity with HBV-DNA levels exceeding the upper limit of normal (ULN) at the study site laboratory. Subjects meeting the following criteria may be enrolled:
• a. HBV viral load \< 1000 copies/mL (200 IU/mL) prior to first dosing, provided antiviral therapy is administered throughout the study period to prevent viral reactivation
• b. Subjects who are anti-HBc(+), HBsAg(-), anti-HBs(-), and HBV-DNA(-) do not require prophylactic antiviral therapy but must undergo close monitoring for viral reactivation.
• Active hepatitis C virus (HCV) infection, defined as positive HCV antibody with detectable HCV-RNA above the lower limit of detection.
• Pregnant or lactating women.
• Presence of severe or uncontrolled systemic diseases, including but not limited to:
• 1\. Cardiac disorders: severe arrhythmias (e.g., complete left bundle branch block, second-degree or higher atrioventricular block, ventricular arrhythmia, or persistent atrial fibrillation), unstable angina, or congestive heart failure (NYHA class ≥ II)
• 2\. Vascular diseases: history of unstable angina, myocardial infarction, transient ischemic attack, or stroke within 6 months prior to enrollment
• 3\. Poorly controlled hypertension: systolic blood pressure \> 140 mmHg or diastolic blood pressure \> 90 mmHg
• 4\. Pulmonary diseases: noninfectious pneumonitis requiring corticosteroid treatment within 1 year before first dosing, or active interstitial lung disease
• 5\. Infectious diseases: active infections requiring systemic therapy, or severe uncontrolled infections
• 6\. Active pulmonary tuberculosis
• 7\. Gastrointestinal diseases: clinically active diverticulitis, intra-abdominal abscess, or intestinal obstruction
• 8\. Hepatic disorders: liver cirrhosis, decompensated liver disease, or acute/chronic active hepatitis
• 9\. Uncontrolled diabetes mellitus: fasting blood glucose (FBG) \> 10 mmol/L
• 10\. Renal dysfunction: urine protein ≥ ++ on routine urinalysis and 24-hour urinary protein \> 1.0 g
• 11\. Psychiatric disorders: severe mental illness that may affect treatment compliance.