In a patient with resectable left posterior buccal mucosal carcinoma involving the lateral border of the tongue and a right-sided small ulcer diagnosed as invasive squamous cell carcinoma, what is the recommended management?

Management Recommendation

This patient requires comprehensive surgical resection of both lesions with bilateral neck dissection, followed by adjuvant radiotherapy or chemoradiotherapy based on final pathologic findings. The presence of bilateral oral cavity squamous cell carcinomas (left posterior buccal mucosa with lateral tongue involvement and right-sided lesion) mandates aggressive surgical management as the primary treatment modality 1.

Treatment Algorithm

Primary Surgical Approach

Proceed with en-bloc resection of both lesions with adequate margins:

• Left-sided lesion: Perform compartmental resection including the posterior buccal mucosa and involved lateral tongue border with minimum 10mm margins. The buccal mucosa compartment should include the three-dimensional space between oral mucosa, vessel plane, and connecting lymphatic structures 2
• Right-sided lesion: Wide local excision with adequate margins
• Oral cavity primaries are best managed with primary surgery rather than primary chemoradiation, particularly for T3/T4 oral cavity cancers 1

Neck Management - Critical Decision Point

Bilateral neck dissection is mandatory given the bilateral disease presentation:

• Left neck: Therapeutic neck dissection (at minimum levels I-IV) given the posterior location and tongue involvement. Tongue lesions demonstrate high rates of bilateral nodal involvement, particularly at levels II and III 3
• Right neck: Elective neck dissection (at minimum levels I-III) even if clinically N0, as depth of invasion >4mm significantly increases occult metastasis risk (28.1% rate in cN0 patients) 4
• Level Ib is the most commonly affected level in buccal mucosa carcinoma, followed by level IIa 5
• Contralateral drainage occurs in 21.6% of tongue cancers with contralateral metastases in 5.4% 6, making bilateral dissection essential

Adjuvant Treatment Decision Tree

Postoperative treatment within 6-7 weeks based on pathologic findings 1:

Adjuvant RT indicated for:

• pT3-4 tumors
• Perineural infiltration (strong predictor of poor outcomes 6)
• Lymphatic infiltration

• 1 invaded lymph node

• Close margins

Adjuvant chemoradiotherapy (cisplatin 100 mg/m² every 3 weeks) mandatory for:

• R1 resection (positive microscopic margins)
• Extracapsular extension
• Both features together show strongest benefit 1

Alternative if cisplatin-unfit: Weekly cisplatin 40 mg/m² has shown non-inferiority, or carboplatin/5-FU, or cetuximab with RT 1

Critical Considerations

Synchronous Primary vs Field Cancerization

The bilateral presentation raises concern for either:

• Two independent primaries (field cancerization effect from tobacco/betel quid exposure)
• Contralateral metastatic spread (less likely given small size of right lesion)

This distinction doesn't change surgical management but affects staging and prognosis discussion.

Reconstruction Planning

Given the extent of resection (posterior buccal mucosa + lateral tongue):

• Plan for functional reconstruction to preserve speech and swallowing
• Microvascular free flap is gold standard for extensive defects
• Regional flaps (submental, island tongue flap) are alternatives for moderate defects 7

Depth of Invasion Assessment

Critical prognostic factor: Depth of invasion (DOI) >4mm significantly increases nodal metastasis risk (87.5% vs 12.5%, p=0.033) 4. DOI >5mm specifically predicts regional recurrence 4. Ensure pathology reports DOI for both lesions.

Common Pitfalls to Avoid

1. Inadequate neck dissection: Unilateral dissection only would be insufficient given bilateral disease and tongue involvement patterns
2. Delayed adjuvant therapy: Must start within 6-7 weeks; delays beyond 11 weeks from surgery worsen outcomes 1
3. Underestimating posterior buccal lesions: These behave more aggressively than anterior lesions with higher regional recurrence rates 8, 5
4. Insufficient margins: Deep margin control is particularly challenging in buccal mucosa; compartmental approach improves margin adequacy 2

Multidisciplinary Requirements

This case must be discussed in MDT including head/neck surgery, radiation oncology, medical oncology, speech pathology, and nutrition support 1. Treatment at high-volume facilities improves outcomes 1.