1. 3. What will you do next? Do an open lymph node biopsy Perform metastatic work ups Do imaging of the oral cavity and neck to determine resectability Proceed with surgery Refer for radiation therapy

2. Metastatic Work-up Staging Imaging for Resectability SurgeryRadiotherapy Overview of Management

3. Lymph Node Biopsy The goal of lymphatic mapping and sentinel lymph node biopsy is to identify and remove the lymph node most likely to contain metastases in the least invasive fashion. * Sentinel node - the first node to receive drainage from the tumor site. This node is the node most likely to contain metastases, if metastases to that regional lymph node basin are present. Recent studies evaluating treatment of an N0 neck have investigated the use of sentinel lymph node biopsy, which attempts to predict the disease status of the neck based on the first echelon of nodes that drain the tumor.

4. Metastatic Work-Up Vigilance for second primary tumors Patients diagnosed with a head and neck cancer are predisposed to the development of a second tumor within the aerodigestive tract Patients with a primary malignancy of the oral cavity or pharynx are most likely to develop a second lesion within the cervical esophagus

5. Once cancer has been proven by biopsy, a CT scan of the chest will be ordered to rule out distant metastasis Contrast-enhanced CT and MRI of the head and neck may be performed for evaluation of the tumor and detection of occult lymphadenopathy CT scanning - best at evaluating bony destruction MRI - determine soft tissue involvement and is excellent at evaluating parotid and parapharyngeal space tumors Chest radiography or chest CT is performed to rule out synchronous lung lesions Serum tumor markers such as alkaline phosphatase and calcium may be determined, but such tests are not standard.

6. Positron Emission Tomography (PET) evaluates neck metastases with a sensitivity equal to that of CT able to detect a higher percentage of lung metastases than chest radiography, bronchoscopy, or CT but specificity ranges from 50% to 80%, and how to treat a patient with a positive PET and an otherwise negative lung workup is still in question most common sites of distant spread are the lungs and bones, whereas hepatic and brain metastases occur less frequently risk for distant metastases is more dependent on nodal staging than on primary tumor size

7. Patterns of Lymph Node Metastasis The cervical lymphatic nodal basins contain between 50 and 70 lymph nodes per side and are divided into seven levels: 1. Level I Level IA is bounded by the anterior belly of the digastric muscle, the hyoid bone, and the midline. Level IB is bounded by the anterior and posterior bellies of the digastric muscle and the inferior border of the mandible. Level IB contains the submandibular gland. 2. Level II is bounded superiorly by the skull base, anteriorly by the stylohyoid muscle, inferiorly by a horizontal plane extending posteriorly from the hyoid bone, and posteriorly by the posterior edge of the sternocleidomastoid muscle. Level II is further subdivided: Level IIA is anterior to the spinal accessory nerve. Level IIB, or the so-called submuscular triangle, is posterior to the nerve.

8. Patterns of Lymph Node Metastasis

9. 3. Level III begins at the inferior edge of level II and is bounded by the laryngeal strap muscles anteriorly, by the posterior border of the sternocleidomastoid muscle posteriorly, and by a horizontal plane extending posteriorly from the inferior border of the cricoid cartilage. 4. Level IV begins at the inferior border of level III and is bounded anteriorly by the strap muscles, posteriorly by the posterior edge of the sternocleidomastoid muscle, and inferiorly by the clavicle. 5. Level V is posterior to the posterior edge of the sternocleidomastoid muscle, anterior to the trapezius muscle, superior to the clavicle, and inferior to the base of skull 6. Level VI is bounded by the hyoid bone superiorly, the common carotid arteries laterally, and the sternum inferiorly. Although level VI is large in area, the few lymph nodes that it contains are mostly in the paratracheal regions near the thyroid gland. 7. Level VII (superior mediastinum) lies between the common carotid arteries and is superior to the aortic arch and inferior to the upper border of the sternum.

11. Staging Clinical staging of the neck is based primarily on palpation, although radiographic studies, including computed tomography (CT) and magnetic resonance imaging (MRI), have been shown to be accurate in detecting positive nodes

12. T1N2bMX

14. Imaging for Resectability Panoramic x-ray of the mandible scanning dental X-ray of the upper and lower jaw shows a two-dimensional view of a half-circle from ear to ear shows a patient's nasal area, sinuses, jaw joints, teeth and surrounding bone can reveal cysts, tumors, bone irregularities the mandible can also have an indentation on its lower border when the patient's masseter has been clenching and grinding shows the entire mandible, including all of its lower border

15. Indications for cortical or rim resection of the mandible as determined by physical examination, CT scan, orthopantomogram, and dental films a. Tumor close to but not involving the periosteum of mandible b. Tumor involving only mandibular periosteum c. Tumor adjacent to cortical bone of mandible with no evidence of invasion beyond superficial cortex d. Tumor adjacent to dentition with no evidence of involvement of periodontal ligament

16. Indications for segmental resection of the mandible as determined by physical examination, CT scan, orthopantomogram, and dental films a.Invasion of the medullary space of the mandible b.Tumor fixation to the occlusal surface of the mandible in the edentulous patient c. Invasion of tumor into the mandible via the mandibular or mental foramen d. Tumor fixed to the mandible following prior radiotherapy to the mandible, particularly if the tumor is located on the occlusal surface e. Tumor adjacent to carious dentition with involvement of the periodontal ligament f. Hypoplastic edentulous mandible with significant loss of vertical height precluding safe performance of a rim resection

17. Contraindications 1.For most cases of oral cancer recurrent after radiation therapy with tumor intimately associated with the mandible, rim resection is contraindicated. In these cases the route and exact location of tumor invasion into the mandible is not predictable. 2. Patients with very hypoplastic mandibles in which oncologically safe resection of the tumor would leave less than 1 cm of bone width and height are not good candidates for rim resection. 3. With the multiple alternative techniques for approaching tumors of the oral cavity and pharynx available, segmental mandibular resection done solely to improve access for tumor extirpation is rarely indicated. 4. Segmental or rim resection for presumed clearance of mandibular lymphatics is not indicated.

18. Pertinent Anatomy 1. Involvement of mandibular lymphatics or the periosteum of the mandible occurs via direct extension of the primary tumor. There is no evidence that tumors of the oral cavity metastasize to involve the mandibular lymphatics or periosteum. 2. Cortical thickness on the occlusal surface of the mandible is significantly less than other areas of the mandible. 3. With atrophy of the edentulous mandible, the occlusal surface is lowered downward, and in the extremely hypoplastic mandible, the alveolar canal may run along the occlusal surface. 4. In the nonradiated mandible, the most frequent route of tumor spread to invade the mandible is via the occlusal surface of the alveolus. This route of spread accounts for approximately 90% of cases in which oral tumors invade the mandible. 5. In previously radiated mandibles, the most frequent route of tumor invasion into the mandible is also via the occlusal surface; however, tumor may also invade along other surfaces, and site of invasion is much less predictable than in the nonradiated cases. 6. Tumor invasion of the mandible follows a leading front of inflammatory bone destruction due to stimulated osteoclastic and osteoblastic activity. 7. In the nonradiated patient, the mylohyoid muscle serves as a barrier to tumor spread from the floor of the mouth; however, this barrier will be breached in larger tumors.

19. OPERATIVE PROCEDURE FOR RIM RESECTION A.Ipsilateral neck dissection is completed; Level I remains in continuity with oral cancer. B. Access to tumor via lingual release or lip-split procedure. C. Lateral periosteal cuts are made intraorally. D. Periosteum is gently elevated toward tumor, If mandibular invasion is evident, the procedure should be converted to a segmental resection. E. Lateral mandibular periosteum is elevated inferiorly exposing lateral cortex of the upper mandible. F. The periosteum of the lower cortex is not elevated. G. Using a sagittal saw or Midas-Rex, a horizontal rim resection is created by cutting horizontally through the bone at least 0.8 to 1 cm from the tumor. Distally and proximally, the bone cuts form a smooth transition with the occlusal surface. Square corners at the ends of the ostectomy site create points of mandibular weakness. H. If the tumor is located on the lingual surface of the mandible, a similar vertical rim resection is performed (lingual plate resection). I. Any soft tissue available along the bone cut should be submitted for frozen section analysis. J. The remaining soft tissue cuts are made, and the tumor is delivered as a pull-through specimen in continuity with the Level I neck dissection.

20. OPERATIVE PROCEDURE FOR SEGMENTAL RESECTION A.Ipsilateral neck dissection is completed; Level I remains in continuity with oral cancer. B. Access to tumor is via lingual release or lip-split procedure. C. Exposure of noninvolved outer cortex of mandible adjacent to area of mandibular involvement is obtained 1.For the dentate patient, the reconstruction plate is contoured, and preliminary holes are drilled in order to return the patient to preoperative occlusal state 2.2. For the edentulous patient the resected specimen will be used to fashion a template from which the bone flap will be contoured. 3. If bone flap reconstruction is not planned, then proceed as in Step 1 above using a locking screw plate to stabilize the bone fragments and restore mandibular arch continuity; this type of reconstruction is recommended for only short-segment, posterior defects in patients who will not be loading the mandible postoperatively (ie, edentulous, elderly patients). D. Segmental cuts are made at least 1.0 cm from suspected bone involvement using a sagittal saw or Midas- Rex. 1.These cuts are made from external to internal following the intraoral mucosal and periosteal cuts. This leaves the tumor held in place by soft tissues of the oral cavity or pharynx. 2. Soft tissue within the alveolar canal at the distal and proximal end of the excision may be submitted for frozen section analysis. Any easily removable soft tissue in the cut bone ends of the mandible should be submitted for frozen section evaluation. E. Completion of soft tissue resection is performed, and the specimen is delivered in continuity with Level I neck dissection. F. Careful back elevation of mucoperiosteum adjacent to incisions will facilitate ease of suturing this tissue to the reconstructive flap.

21. Cortical or rim mandibulectomy – if (+) adherence to mandibular periosteum without bony erosion Segmental resection – if (+) mandible invasion

22. Resection of retromolar trigone tumors: usually requires a marginal or segmental mandibulectomy with a soft-tissue and/or osseous reconstruction in order to maximize a patient's postoperative ability for functional speech and swallowing Ipsilateral elective and therapeutic neck dissection is performed because of the risk of metastasis to the regional lymphatics

23. Results of the Patient Head & neck examinations: ⊖ Chest X-ray: ⊖ Panoramic x-ray of the mandible: lytic lesion of the body of the mandible near the angle

24. References: Schwartz’s Principles of Surgery, 8 th ed. Sabiston Textbook of Surgery, 18 th ed. http://www.carleconnect.com/CSP/CSP%20Fal l/7.%20Fall06.Brockenbrough.OralCancers.pdf http://www.lib.uiowa.edu/commons/oto/iow a/Part3/P3G3.htm