# Oral Squamous Cell Carcinoma: Principles for the OMFS Surgeon

## Introduction

Oral squamous cell carcinoma (OSCC) accounts for approximately 90% of all malignant neoplasms of the oral cavity. The OMFS surgeon plays a critical role in early detection, biopsy, surgical resection, and reconstruction. Understanding the principles of oncologic surgery, staging, and multidisciplinary management is essential for optimal patient outcomes.

## Epidemiology and Risk Factors

Approximately 54,000 new cases of oral and oropharyngeal cancer are diagnosed annually in the United States, with a male-to-female ratio of approximately 2:1, though this gap is narrowing. Major risk factors include tobacco use (both smoking and smokeless), alcohol consumption (which has a synergistic effect with tobacco), betel quid and areca nut chewing (particularly in Southeast Asia), HPV infection (primarily HPV-16, which is most relevant to oropharyngeal cancer), chronic ultraviolet exposure (affecting the lip vermilion), and immunosuppression. Potentially malignant disorders that may precede OSCC include leukoplakia, erythroplakia, oral submucous fibrosis, and proliferative verrucous leukoplakia.

## Clinical Presentation

The most common sites for OSCC include the lateral tongue, floor of mouth, retromolar trigone, soft palate, and gingiva. It typically presents as a non-healing ulcer, indurated mass, or red or white patch persisting for more than 2 to 3 weeks. Advanced lesions may cause pain, dysphagia, trismus, paresthesia, or cervical lymphadenopathy. A high index of suspicion should be maintained for any persistent oral mucosal abnormality, especially in patients with known risk factors.

## Diagnostic Workup

### Biopsy

An incisional biopsy of the most suspicious area is performed, avoiding the necrotic center and including adjacent normal tissue for comparison. A punch biopsy or scalpel biopsy is standard; brush biopsy may serve a screening role but is not definitive.

### Imaging

CT with contrast of the head and neck evaluates tumor extent and cervical lymph nodes. MRI is valuable for assessing soft-tissue invasion, including perineural spread and tongue base involvement. PET-CT detects distant metastases and occult nodal disease. Chest CT screens for pulmonary metastases. Panoramic radiograph and CBCT assess mandibular involvement.

### Staging (AJCC 8th Edition TNM)

| T Stage | Size | Depth of Invasion (DOI) | Key Features |
|---|---|---|---|
| T1 | ≤2 cm | ≤5 mm | — |
| T2 | ≤2 cm or >2-4 cm | >5 mm to ≤10 mm (if ≤2 cm); ≤10 mm (if >2-4 cm) | — |
| T3 | >4 cm | >10 mm (any size) | — |
| T4a | Any | Any | Cortical bone, maxillary sinus, or facial skin invasion |
| T4b | Any | Any | Masticator space, pterygoid plates, skull base, or ICA encasement |

T staging is based on tumor size and depth of invasion (DOI), a critical prognostic factor added in the 8th edition. T1 designates a tumor 2 cm or less with DOI of 5 mm or less. T2 includes tumors 2 cm or less with DOI greater than 5 mm but 10 mm or less, or tumors greater than 2 cm but 4 cm or less with DOI of 10 mm or less. T3 designates tumors greater than 4 cm or with DOI greater than 10 mm. T4a involves invasion through cortical bone, the maxillary sinus, or skin of the face. T4b involves invasion of the masticator space, pterygoid plates, skull base, or encasement of the internal carotid artery. N staging accounts for extranodal extension (ENE), which is a major adverse prognostic factor.

![Clinical photograph of a squamous cell carcinoma of the lateral tongue presenting as an indurated ulcerative lesion](/images/residency/omfs/oscc-lateral-tongue.jpg)

## Surgical Principles

### Resection

Wide local excision with a minimum 1 cm clinical margin in all dimensions is the standard. Frozen section analysis of margins is performed intraoperatively. Mandibulectomy (marginal or segmental) is indicated when tumor abuts or invades bone. Maxillectomy is performed for tumors involving the hard palate or maxillary alveolus.

### Neck Dissection

Elective neck dissection is recommended for tumors with DOI greater than 4 mm or clinical T2 and above, even in the clinically N0 neck. Sentinel lymph node biopsy is an emerging alternative for early-stage tumors. A supraomohyoid neck dissection (levels I-III) is standard for clinically N0 oral cavity tumors, while a comprehensive neck dissection (levels I-V) is performed for clinically node-positive disease. Extranodal extension is a major adverse prognostic factor that warrants adjuvant chemoradiation.

### Reconstruction

Small defects are closed primarily. Local and regional flaps such as the buccal fat pad, nasolabial flap, and submental flap are used for moderate defects. Free tissue transfer is employed for large defects, with common options including the radial forearm free flap (soft tissue), fibula free flap (composite reconstruction), and anterolateral thigh flap. Immediate reconstruction optimizes function and quality of life.

![Axial CT scan demonstrating a large oral cavity tumor with mandibular invasion and cervical lymphadenopathy](/images/residency/omfs/oscc-ct-scan.jpg)

## Adjuvant Therapy

Radiation therapy is indicated for advanced-stage disease (T3/T4), positive or close margins, perineural invasion, and lymphovascular invasion. Concurrent chemoradiation with cisplatin-based regimens is indicated when positive margins or extranodal extension are present. Immunotherapy with checkpoint inhibitors such as pembrolizumab and nivolumab is approved for recurrent or metastatic OSCC, with PD-L1 status guiding treatment decisions.

## Prognosis

Overall 5-year survival is approximately 65% and is highly stage-dependent. Early-stage (I/II) disease carries a 70-90% survival rate, while advanced-stage (III/IV) disease has a 30-50% survival rate. Key prognostic factors include stage, depth of invasion, nodal status, extranodal extension, margin status, and perineural invasion.

![Surgical specimen showing a resected oral squamous cell carcinoma with adequate margins marked with sutures for orientation](/images/residency/omfs/oscc-specimen.jpg)

## Clinical Pearls

Any oral mucosal lesion persisting beyond 2 to 3 weeks without improvement warrants biopsy. Depth of invasion is a critical factor in the AJCC 8th edition staging and drives decisions regarding neck dissection. Elective neck dissection is recommended for tumors with DOI greater than 4 mm even in the clinically N0 neck. Multidisciplinary tumor board discussion is essential for treatment planning. The OMFS surgeon must be prepared to provide immediate reconstruction after ablative surgery.

## References

1. Amin MB, Edge SB, Greene FL, et al., eds. *AJCC Cancer Staging Manual*. 8th ed. Springer; 2017.
2. National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology: Head and Neck Cancers. Version 1.2025.
3. Shah JP, Gil Z. Current concepts in management of oral cancer — surgery. *Oral Oncol*. 2009;45(4-5):394-401.
4. Zanoni DK, Montero PH, Migliacci JC, et al. Survival outcomes after treatment of cancer of the oral cavity (1985-2015). *Oral Oncol*. 2019;90:115-121.