oral cavity lesions with suspected mandibular involvement, most surgeons would start with a CT scan with contrast of the head and neck to evaluate the primary site lesion and regional lymphatics.
A PET/MRI and neck CT with IV contrast are obtained. The CT of the neck shows significant thinning of the lingual cortex of the mandible at the site of the lesion and the absence of the buccal cortex superiorly. The inferior alveolar canal appears intact (see Figure 2.2). The PET/MRI shows intense activity at the primary lesion without clear evidence of lymph node metastases. On MRI, there is an abnormal marrow signal at the location of the lesion, suspicious for marrow invasion. There is no evidence of involvement of the mandibular canal.
Question: Based on imaging findings, what is the clinical stage of the disease?
Answer: Since there is radiographic evidence of osseous invasion, the disease is upstaged to T4aN0M0, stage IVa.
Question: What is the recommended course of treatment?
Answer: Oral cavity SCC is primarily treated with surgery, followed by risk‐adjusted adjuvant treatment. In this case, the recommended treatment is composite resection of the lesion with segmental mandibulectomy, selective neck dissection (levels I–III), and reconstruction with microvascular free tissue transfer, such as fibula free flap, to provide the best functional outcome.
The patient undergoes segmental mandibulectomy and selective neck dissection with fibula free flap reconstruction. The final pathology shows a 2 × 1 cm ulcerative SCC of the gingiva with invasion of the mandible. All margins are free of tumor (>5 mm). There is no perineural invasion. There is a microscopic focus of carcinoma present in 1 out of 32 lymph nodes (level Ib node, 2.3 cm) with no evidence of extracapsular extension.
Question: What is the pathologic stage?
Answer: Based on mandibular invasion and nodal involvement, the pathologic stage is pT4aN1M0, stage IVa.
Question: What adjuvant treatment regimen would you recommend to this patient?
Answer: In spite of negative margins and no perineural invasion, advanced T stage and involvement of regional nodes warrant adjuvant radiotherapy. There is no indication for chemotherapy (positive margins and extranodal extension). Therefore, adjuvant radiotherapy is adequate.
FIGURE 2.2 These axial images are from the patient's CT (a, b) as well as the T1‐weighted MRI (c) and fused PET/MRI (d). Note the lesion of the right mandible with associated cortical erosion and hypermetabolism.
Key Points
Alveolus SCC is less common than tongue or floor of mouth cancers.
Achieving negative margin resection (>5 mm) is an extremely important objective in the treatment of alveolar cancers.
To achieve negative margin resection, most alveolar tumors will require resection of the underlying bone. Determining the extent of the mandibulectomy required to achieve negative margins can be challenging.
It is accepted that if there is no bone erosion on CT or MRI, and there is enough height of the bone, marginal mandibulectomy can achieve negative margin resection. The remaining mandible should have at least a height of 1 cm.
If there is bone erosion on CT imaging or MRI shows changes in the bone marrow signal, segmental mandibulectomy is recommended.
There is no level I data on the best method to determine bone involvement. Cone beam CT is considered a very sensitive method.
In good risk candidates, osseous reconstruction with fibula, scapula, or iliac crest free flap is recommended.
Osteocutaneous radial forearm or vascularized rib graft has been described and used in patients who are not good candidates for fibula or scapula. However, the harvested bone is not thick enough to host implants.
CASE 3
Michael G. Moore
History of Present Illness
A 68‐year‐old white male presents with a chief complaint of a painful sore around his right lateral maxillary teeth. He states he initially thought it was related to a dental infection, but after having a tooth pulled, the area has continued to enlarge.
Question: What are the other important points in history taking?
Answer:
Presence of other adjacent loose teeth.
Facial numbness.
Difficulty in opening the mouth.
Dysphagia, odynophagia.
Voice changes.
Presence of neck mass.
For maxillary lesions, it is always important to determine the extent of the disease. Signs such as loose teeth, difficulty in opening the mouth (trismus), and facial numbness (perineural invasion) could provide critical clinical clues to the extent of disease and aggressive behavior.
Question: What additional aspects of the history and risk factors should be investigated?
Answer:
Tobacco or alcohol use.
Any history of head and neck cancers.
Past medical history for significant diseases: peripheral vascular disease, diabetes, autoimmune diseases, chronic kidney disease, coagulation disorders, to name a few.
This patient has a history of 10 pack‐year smoking but quit 25 years ago. He drinks alcohol socially with no history of excessive drinking. There is no history of significant diseases or malignancy.
Physical Examination
Oral cavity examination shows a 3 × 2 cm ulcerative lesion on the buccal aspects of teeth #2 to #4 with slight extension onto the palatal aspect of these teeth. No obvious loose teeth, but there is fleshy tissue at the site of the previously extracted tooth #3. His upper teeth are otherwise intact.
Neck exam revealed a 1.5 cm, firm, mobile, slightly tender right level 1b neck mass. No other neck masses were noted. No trismus or paresthesias noted. The rest of the examination is within the normal limits. Cranial nerves II–XII
