Clinical Study Evaluating the Proper Surgical Safety Margin for Early Stage Oral Tongue Cancers

A prospective multicenter randomized non-inferiority clinical trial, to evaluate the efficacy and safety of 1.0 cm-safety margin surgery, compared with 1.5 cm safety margin surgery for cT1-2N0 oral tongue cancer

Summary:

A current standard primary treatment for oral tongue cancer is a curative surgical resection with/without adjuvant radiation treatments (or chemoradiation).

In pathological analysis of surgical specimens, more than 5 mm of non-tumorous tissues from the tumor border is regarded as a safe negative resection margin, according to the NCCN guideline (the National Comprehensive Cancer Network, Dec 10. 2020). To achieve this clear margin, surgeons are apt to use a 1.0 to 1.5 cm safety margin around the gross tumor during surgery, considering 30-50% tumor shrinkage in tissue fixation process.

Many previous retrospective data have been reported to suggest the optimal or proper surgical extent for oral tongue cancer. Wider resection can lead to better local control, however, it sacrifices more normal tissue, resulting in the functional deficit of tongue (speech and swallowing), even with reconstruction.

Unfortunately up to now, no prospective comparison of a different surgical safety margin for oral tongue cancer have been conducted to draw a more solid conclusion. Particularly in early stage oral tongue cancer (cT1-2N0), some study results have suggested that less than 5 mm resection margin in pathology specimens can be also safe and effective in terms of tumor control.

To achieve a well-grounded result about the proper surgical safety margin in early stage (cT1-2N0) oral tongue cancer, we will compare the outcomes of the two (1.5 cm versus 1.0 cm) surgical safety margin in curative resection for cT1-2N0 oral tongue cancer.

Randomization

* The randomized allocation table was made by stratified block randomization methods with 1:1 ratio according to each participating surgeon and tumor stage.
* Baseline number (BN) should be provided to the subjects in the order of the date of surgery.

Surgical Procedure

* The study includes T1-2N0 oral tongue cancer patients. For the management of the primary lesion, wide resection with 1.0- or 1.5-cm surgical safety margin should be performed according to the results of study allocation.
* Neck management can be resection of primary tumor without neck dissection, with ipsilateral or bilateral neck dissection (guided by tumor location) or with sentinel lymph node biopsy, according to the NCCN guideline (version 1.2021).

Evaluation of the surgical safety margin

* The surgical safety margin should be meticulously evaluated in the pathology specimens in all directions.
* The surgical margins less than 0.3 or 0.5 cm in final pathology results are considered as the close surgical margin.

Adjuvant Treatment

* The adjuvant treatments either radiotherapy or chemoradiotherapy are conducted if indicated following the NCCN guideline.
* The follow-up after completion of the definitive treatment are made following the NCCN guideline.

Efficacy evaluation

* The primary outcomes are determined with 2-year local control rates after the completion of the curative treatments.
* The secondary outcomes are determined with the 5-year disease-free survival rates and speech/articulation functional analysis.

Eligibility Criteria:
Inclusion Criteria:

* Pathologically proven oral tongue squamous cell carcinoma
* Stage cT1-2N0M0 tumors
* Treatment-naïve tumor
* American Society of Anesthesiologists (ASA) physical status classification 1-3.
* Patients who give a written informed consent voluntarily.

Exclusion Criteria:

* cT3-4 or N(+) tumors
* Recurrent tumors or salvage surgery
* Patients who have had a previous head and neck surgery and radiation treatment.
* Patients who have other head and neck cancer, within the last 5 years.