Postoperative Radiotherapy Combined With Nimotuzumab Followed by Benmelstobart in High-Risk Patients With Head and Neck Squamous Cell Carcinoma

Inclusion criteria

• Age ≥ 18 years.
• Patients ineligible for cisplatin chemotherapy, defined as meeting any of the following:① Age > 70 years;② Renal insufficiency (creatinine clearance < 50 mL/min; criterion ⑩ below does not apply if this criterion is met);③ Severe tinnitus or hearing impairment (requiring hearing aid, or audiometry showing ≥ 25 dB loss at two consecutive frequencies);④ Unable to receive intravenous hydration (e.g., due to cardiac dysfunction or other comorbidities, as judged by the investigator);⑤ Neuropathy > Grade 1;⑥ Patient refusal of chemotherapy.
• Histologically confirmed locally advanced head and neck squamous cell carcinoma (AJCC 8th edition Stage III-IVB), including oral cavity cancer, HPV-negative/unrelated oropharyngeal cancer, hypopharyngeal cancer, and laryngeal cancer.
• Underwent radical surgery with at least one high-risk feature:

Extracapsular extension (ECE) of lymph node metastasis; Close margin (< 1 mm) or positive margin;

• 4 metastatic lymph nodes, or multiple perineural invasions.
• No evidence of distant metastasis on imaging.
• Sufficient tumor tissue available for EGFR and PD-L1 testing; for oropharyngeal cancer, HPV/p16 testing is required (testing may be waived if results are already available).
• Expected survival ≥ 6 months.
• ECOG performance status 0-1.
• Adequate hematologic function:

WBC ≥ 3 × 10⁹/L; ANC ≥ 1.5 × 10⁹/L; Platelets ≥ 100 × 10⁹/L; Hemoglobin ≥ 90 g/L.

• Adequate renal function:Serum creatinine ≤ 1.5 × ULN or creatinine clearance (CrCl) > 50 mL/min (calculated by Cockcroft-Gault formula):

Female: CrCl = (140 - Age) × Weight (kg) × 0.85 / (72 × Scr (mg/dL)) Male: CrCl = (140 - Age) × Weight (kg) × 1.00 / (72 × Scr (mg/dL))

• Adequate hepatic function:

Total bilirubin ≤ 1.5 × ULN; AST ≤ 2.5 × ULN; ALT ≤ 2.5 × ULN.

• Women of childbearing potential: negative serum or urine pregnancy test within 14 days before enrollment, and agreement to use effective contraception during the study.Male subjects: use effective contraception from the start of treatment until 180 days after the last study drug administration.
• Voluntary participation in the study, signed written informed consent, good compliance, and willingness to comply with follow-up procedures.

Exclusion criteria

• Prior radiotherapy for head and neck cancer before enrollment.
• Prior treatment with similar immunological or targeted agents.
• Participation in another interventional clinical trial within 30 days prior to screening.
• Evidence of distant metastasis.
• History of other malignancy within the previous 5 years, except cured carcinoma in situ of the cervix, non-melanoma skin cancer, localized differentiated thyroid cancer (papillary / follicular), localized prostate cancer, and ductal carcinoma in situ.
• Uncontrolled concurrent medical conditions (e.g., heart failure, diabetes mellitus, hypertension, thyroid disease, psychiatric disorders, etc.).
• Known HIV infection, active viral hepatitis, or active tuberculosis.
• Major surgical procedure within 30 days before the first dose of study medication, or planned major surgery during the study.
• Hypersensitivity to any study drug or their components.
• Pregnancy (confirmed by serum or urine HCG test) or lactating women; subjects of childbearing potential unwilling or unable to use effective contraception (for both male and female subjects) until at least 6 months after the last study treatment.
• Subjects considered inappropriate for study participation by the investigator.
• Subjects unwilling to participate in the study or unable to provide written informed consent.