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.
Histologically proven squamous cell carcinoma of oral cavity will be included
Clinical stage T1-T4, N1, M0
cN1 neck on clinical examination and imaging (CT/MRI)
Single node which is FNAC proven without any other significant nodes.
Recurrent cases
Multiple significant nodes
Nodes clinical/radiological with ENE
Single metastatic node at level III/IV/V
Parallel
Selective Neck Dissection (Levels I-IV)
Procedure/SurgerySelective neck dissection will include removal of cervical lymph node levels Ia, Ib, IIa, IIb, III, and IV on the ipsilateral side while preserving uninvolved non-lymphatic structures. The primary oral cavity tumor will be resected according to oncologic principles with reconstruction as required. Contralateral neck management and adjuvant therapy will be provided according to institutional protocols and final histopathological findings.
Modified Neck Dissection (Levels I-V)
Procedure/SurgeryModified neck dissection will include removal of cervical lymph node levels Ia, Ib, IIa, IIb, III, IV, and V on the ipsilateral side while preserving the spinal accessory nerve, internal jugular vein, and sternocleidomastoid muscle whenever oncologically appropriate. The primary oral cavity tumor will be resected according to oncologic principles with reconstruction as required. Contralateral neck management and adjuvant therapy will be provided according to institutional protocols and final histopathological findings.
Regional Recurrence-Free Survival (RRFS)
Regional recurrence-free survival is defined as the time from the date of definitive surgery to the first documented regional recurrence in the cervical lymph nodes or death from any cause, whichever occurs first. Regional recurrence will be confirmed by clinical examination, imaging, and histopathological evaluation whenever feasible.
Overall Survival (OS)
Overall survival is defined as the time from definitive surgery until death from any cause.
Disease-Free Survival (DFS)
Disease-free survival is defined as the time from definitive surgery to the first documented local, regional, or distant recurrence, or death from any cause.
Level-wise Cervical Lymph Node Metastasis
Distribution of histopathologically confirmed metastatic lymph nodes according to cervical nodal level.
Nodal Yield
Total number of lymph nodes retrieved during neck dissection and confirmed by histopathological examination.
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