Neck Observation or Elective Neck Dissection in CT1N0M0 OSCC

To evaluate the clinical outcomes of 2-year lymph node metastasis rate, disease-free survival, overall survival, and health-related quality of life in the patients with cT1N0M0 oral squamous cell carcinoma, who receive primary lesion resection combined with elective neck dissection or primary lesion resection only.

For the patients with cT1N0M0 oral squamous cell carcinoma (OSCC), surgical resection of primary lesion is the preferred treatment. However, there are still debates on the neck management, some surgeons suggest elective neck dissection (END), and some surgeons suggest neck observation (NOB). The advantage of elective neck dissection is to clear the potential occult neck lymph node metastasis (about 15%), which could not be detected by clinical examination and imaging examination, and the disadvantage of END is to cause neck deformity, large scars, stiff neck and shoulders, difficulty in raising shoulders, and increase medical costs. The disadvantage of NOB is the risk of lymph node metastasis and disease progression. However, recent retrospective studies show that END has no potential benefit in improving survival in cT1N0M0 patients. The aim of the present trial is to compare the clinical outcomes between the cT1N0M0 OSCC patients, who receive primary lesion resection combined with elective neck dissection or primary lesion resection only, on the aspects of 2-year lymph node metastasis rate, disease-free survival, overall survival, and health-related quality of life. A total number of 300 patients will be recruited, including 150 patients in the experimental arm and 150 patients in the control arm. Experimental arm: radical resection of the primary lesion only, with neck observation, the safety margins of the primary lesion are 1.0-1.5cm far away from the palpable margins of the lesion. Control arm: radical resection of the primary lesion with 1.0-1.5cm safety margins, and elective neck dissection. A complete medical history will be obtained and tumor assessment will be performed at baseline. Patients will be followed-up by every three months in the first 2 years, every six months in the next 3-5 years, and once a year thereafter until death or data censoring. Two-year lymph node metastasis rate, disease-free survival, overall survival, and health-related quality of life will be collected and analyzed.

Eligibility Criteria:
Inclusion Criteria:

* Tumor site: tongue, gingiva, buccal mucosa, floor of mouth, hard palate, retromolar eara
* Clinical stage is cT1N0M0 (AJCC 8th edition)
* Pathological diagnosis of squamous cell carcinoma
* Sign the informed consent form

Exclusion Criteria:

* More than 2 lesions found in the oral cavity
* Known history of malignant tumor within five years (unless the patient has undergone curative treatment and there is no disease recurrence within 5 years since the start of treatment)
* History of unilateral or bilateral neck dissection in the past
* History of previous head and neck radiotherapy
* Pregnant or lactating women
* Severe, uncontrolled infection or known HIV infection; or previous organ transplantation, stem cell or bone marrow transplantation
* Participated in other clinical studies within 30 days before enrollment
* Other circumstances that the researcher considers unsuitable for participation in the study