Clinical trials

The goal of this clinical trial is to learn whether selective neck dissection involving lymph node levels I-III is as effective as selective neck dissection involving levels I-IV in treating adults with clinically node-negative (cN0) oral squamous cell carcinoma undergoing curative surgery. It will also evaluate whether extending the neck dissection to level IV affects cancer control, surgical complications, shoulder function, and quality of life. The main questions it aims to answer are: * Does selective neck dissection of levels I-III provide regional recurrence-free survival comparable to selective neck dissection of levels I-IV? * Does extending the neck dissection to level IV improve overall survival, disease-free survival, or reduce regional recurrence? * Does selective neck dissection of levels I-III result in less postoperative morbidity, better shoulder function, and improved quality of life compared with selective neck dissection of levels I-IV? Researchers will compare patients undergoing selective neck dissection of levels I-III with those undergoing selective neck dissection of levels I-IV to determine whether routine removal of level IV lymph nodes provides additional oncological benefit while maintaining acceptable functional outcomes. Participants will: * Undergo surgery for oral squamous cell carcinoma with random assignment to selective neck dissection of either levels I-III or levels I-IV. * Receive standard postoperative treatment, including radiotherapy or chemoradiotherapy when indicated according to the final pathology report. * Attend scheduled follow-up visits for clinical examinations and surveillance for cancer recurrence. * Undergo assessments of shoulder function, sensory function, postoperative complications, and quality of life using validated questionnaires at predefined follow-up intervals.

Oral cavity squamous cell carcinoma (OCSCC) frequently metastasizes to cervical lymph nodes, and the extent of neck dissection remains an area of ongoing debate in patients with clinically node-positive (cN1) disease. While modified neck dissection (MND, levels I-V) is widely practiced, selective neck dissection (SND, levels I-IV) may provide equivalent oncologic outcomes with reduced surgical morbidity. However, high-quality randomized evidence comparing these approaches is lacking. The ExteNT N1 Trial is a prospective, randomized, open-label, parallel-group clinical trial designed to compare selective neck dissection (levels I-IV) with modified neck dissection (levels I-V, preserving the spinal accessory nerve, internal jugular vein, and sternocleidomastoid muscle) in patients with resectable cN1 oral cavity squamous cell carcinoma. Eligible participants will be randomized in a 1:1 ratio to either treatment arm. The primary endpoint is 3-year regional recurrence-free survival (RRFS), along with postoperative quality of life measured using the Neck Dissection Impairment Index (NDII). Secondary endpoints include overall survival, disease-free survival, level-wise nodal involvement, nodal yield, shoulder function (Constant-Murley Score, SPADI, and Arm Abduction Score), postoperative complications including chyle leak, and other surgical morbidities. This trial aims to generate level I evidence regarding the optimal extent of neck dissection for cN1 OCSCC, balancing oncologic safety with preservation of postoperative function and quality of life.