The Efficacy and Safety of De-escalated Postoperative Radiotherapy in Locally Advanced HNSCC With pCR/MPR

Prior treatment

• Neoadjuvant therapy or radical surgery was not completed.
• Recurrence or distant metastasis occurred before postoperative radiotherapy.
• There are contraindications for radiotherapy, chemotherapy, immunotherapy and targeted therapy.
• Patients with active tuberculosis infection found by history or CT examination, or patients with active tuberculosis infection history within 1 year prior to enrollment, or patients with active tuberculosis infection history before 1 year without formal treatment.

Other illness

• A history of other malignant tumors within the previous 5 years or at the time of enrollment, except for cured skin basal cell carcinoma and cervical in situ cancer, as well as thyroid papilloma.
• Uncontrolled cardiac clinical symptoms or diseases.
• Serious infections.
• A history of immunodeficiency, including HIV-positive status or other acquired congenital immunodeficiency diseases, or a history of organ transplantation and bone marrow transplantation.
• Active hepatitis B (HBV DNA ≥ 2,000 IU/mL or 10,000 copies/mL) or hepatitis C (positive HCV antibody test and HCV RNA above the lower limit of detection).
• Known history of psychotropic drug abuse, alcoholism and drug use.

Other

• Pregnant or lactating women.
• Not suitable for inclusion, as judged by the investigator.

• Untreated, histologically confirmed head and neck squamous cell carcinoma (oral cavity, oropharynx, hypopharynx or larynx), staging T3-4N0M0 or T1-4N1-3M0, III-IVB, according to the eighth edition of the AJCC staging system; within 6 weeks after receiving neoadjuvant therapy and radical surgery.
• Pathological evaluation of surgical specimens was pCR (pathologic complete response, no viable tumor cells) or MPR (Major pathologic response, residual viable tumor cells≤10%).
• Negative surgical margin.
• No extranodal extension.
• Aged ≥ 18 years and ≤ 70 years.
• Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 2.
• Life expectancy of more than 6 months.
• Adequate organ function, based on meeting all of the following criteria (no blood components and cytologic growth factors were received within 14 days prior to the test):
  • Hemoglobin ≥ 75 g/L; absolute neutrophil count ≥ 1.5 × 10\^9/L; and platelet count ≥ 100 × 10\^9/L;
  • Serum albumin ≥ 25 g/L;
  • Total bilirubin ≤ 1.5 × upper limit of normal (ULN); ALT and AST ≤ 2.5 × ULN;
  • Serum creatinine ≤ 1.5 × ULN;
  • Activated partial clotting enzyme time and international standardized ratio (INR) ≤ 1.5 × ULN (Patients on stable doses of anticoagulant therapy such as low molecular weight heparin or warfarin with INR within the expected treatment range of anticoagulants can be screened ).
• Women of childbearing age should agree to the use of contraception (e.g., intrauterine devices, birth control pills, or condoms) during treatment and for 3 months thereafter.
• The regimen of neoadjuvant therapy can be determined by the clinician.
• Subjects voluntarily join the study and sign an informed consent form, with good compliance.