Lip and Oral Cavity Carcinoma

T Category T Criteria TX Primary tumor cannot be assessed Tis Carcinoma in situ T1 Tumor ≤ 2 cm, ≤ 5 mm DOI; DOI is not tumor thickness T2 Tumor ≤ 2 cm, DOI > 5 mm and ≤ 10 mm; or tumor > 2 cm but ≤ 4 cm, and DOI ≤ 10 mm T3 Tumor > 4 cm or tumor ≥ 10 mm DOI, but < 20 mm T4 Moderately advanced or very advanced local disease T4a Moderately advanced local disease; T4a is defined as moderately advanced local disease, tumor invading adjacent structures only (e.g., through cortical bone of mandible or maxilla, or involves maxillary sinus or skin of face) or extensive tumor with bilateral tongue involvement &/or DOI larger than 20 mm T4b Very advanced local disease; tumor invades masticator space, pterygoid plates, or skull base &/or encases ICA


T | Definition of Primary Tumor
N | Definition of Regional Lymph Node: Clinical (cN) and Pathological (pN)

N Category N Criteria
Clinical (cN) NX Regional lymph nodes cannot be assessed N0 No regional lymph node metastasis N1 Metastasis in single ipsilateral node ≤ 3 cm and ENE(-)

N2
Metastasis in single ipsilateral node larger than 3 cm but not larger than 6 cm in greatest dimension and ENE(-); or metastases in multiple ipsilateral lymph nodes, none larger than 6 cm in greatest dimension and ENE(-); or in bilateral or contralateral lymph nodes, none larger than 6 cm in greatest dimension and ENE (-)

N2a
Metastasis in single ipsilateral lymph node larger than 3 cm but not larger than 6 cm in greatest dimension, and ENE(-)

N2b
Metastasis in multiple ipsilateral lymph nodes, none larger than 6 cm in greatest dimension, and ENE(-)

N2c
Metastasis in bilateral or contralateral lymph nodes, none larger than 6 cm in greatest dimension, and ENE(-) N3 Metastasis in lymph node larger than 6 cm in greatest dimension and ENE(-); or metastasis in any node(s) and clinically overt ENE(+)

N3a
Metastasis in lymph node larger than 6 cm in greatest dimension and ENE(-)

N3b
Metastasis in any node(s) and clinically overt ENE (+) Pathological N (pN) NX Regional lymph nodes cannot be assessed N0 No regional lymph node metastasis N1 Metastasis in single ipsilateral lymph node, 3 cm or smaller in greatest dimension ENE(-)

N2
Metastasis in single ipsilateral lymph node, 3 cm or smaller in greatest dimension and ENE(+); or larger than 3 cm but not larger than 6 cm in greatest dimension and ENE(-); or metastases in multiple ipsilateral lymph nodes, none larger than 6 cm in greatest dimension and ENE(-); or in bilateral or contralateral lymph nodes, none larger than 6 cm in greatest dimension, ENE(-)

N2a
Metastasis in single ipsilateral or contralateral lymph node 3 cm or smaller in greatest dimension and ENE(+); or single ipsilateral node larger than 3 cm but not larger than 6 cm in greatest dimension and ENE(-)

N2b
Metastasis in multiple ipsilateral nodes, none larger than 6 cm in greatest dimension and ENE(-)

N2c
Metastasis in bilateral or contralateral lymph nodes, none larger than 6 cm in greatest dimension and ENE(-)

N3
Metastasis in lymph node larger than 6 cm in greatest dimension and ENE(-); or in single ipsilateral node larger than 3 cm in greatest dimension and ENE(+); or multiple ipsilateral, contralateral, or bilateral nodes any with ENE(+)

N3a
Metastasis in lymph node larger than 6 cm in greatest dimension and ENE(-)

N3b
Metastasis in single ipsilateral node larger than 3 cm in greatest dimension and ENE(+); or multiple ipsilateral, contralateral, or bilateral nodes any with ENE(+)  -Tend to invade tongue musculature primarily (intrinsic and then extrinsic) -Can extend posteriorly to glossotonsillar junction and laterally or anteriorly into FOM • Regional lymphatic spread ○ Lymph node metastases generally follow predictable and orderly pattern of spread ○ In general, spread goes from upper to middle to lower cervical nodes ○ Cancer of lip (low potential for metastases) -Submental (level IA) and submandibular (level IB) nodes ○ Cancer of alveolar ridge or hard palate (low potential for metastases) -Submandibular (level IB) -Jugular (levels II-IV) -Retropharyngeal (less commonly) ○ Primary site closer to midline increases risk of bilateral spread to cervical nodes ○ Anterior superior mediastinal nodes considered regional nodes (

Staging
• T Staging ○ T staging is primarily based on size of primary lesion but is also influenced by DOI -DOI can be determined clinically by imaging and by pathologic evaluation of resected specimen -To determine DOI on imaging, "horizon" line is drawn through/along site of primary tumor, through expected location of normal basement membrane, correlating with nearest edges intact or normal mucosa □ Perpendicular line is then drawn from horizon line to deepest margin of infiltrating tumor □ This 2nd line is measured and designated DOI -While DOI is best understood and evaluated in terms of histologic analysis, coronal and sagittal imaging planes are useful in to provide reasonable estimate of DOI ○ Stages -Tis: Represents carcinoma in situ and is histologic diagnosis, generally below sensitivity for imaging modalities -T1: Tumor ≤ 2 cm, DOI ≤ 5 mm -T2: Tumor ≤ 2 cm, DOI > 5 mm, and ≤10 mm or tumor >2 cm but ≤ 4 cm, and DOI ≤ 10mm -T3: Tumor > 4 cm or any tumor with DOI > 10 mm but ≤ 20 mm -T4a: Moderately advanced or very advanced local disease □ Invades cortical bone of maxilla or mandible □ Involves maxillary sinus □ Invades skin of face □ Bilateral tongue involvement □ DOI > 20 mm -T4b: Tumor invades masticator space, pterygoid plates or skull base, or encases internal carotid artery ○ Involvement of extrinsic tongue musculature no longer used as staging criteria ○ CT is less sensitive than MR in identifying PNTS, but PNTS is occasionally demonstrated as enlarged, enhancing V3 of trigeminal nerve, enlarged inferior alveolar nerve canal, widening of foramen ovale, or as distal facial nerve branch involvement of cheek ○ CT with bone windows valuable in evaluating cortical bone invasion ○ MR can be useful in evaluation of extent of medullary cavity involvement after violation of mandibular cortex -Replaced bone marrow is easier to appreciate on precontrast T1WI • N Staging ○ CECT is most common modality utilized for initial nodal staging; but MR and PET/CT are useful and are performed as initial modalities in some centers ○ When using CECT, multiple features of nodes should be evaluated to determine possibility of metastatic disease, including size, shape, density, necrosis, and possible ENE -Malignant lymphadenopathy results in enlarged lymph nodes ± necrosis ○ Regional lymph node staging can be categorized clinically (cN) prior to treatment or pathologically (pN) following resection of primary tumor and selected nodal groups -Imaging findings support clinical classification ○ Midline nodes are considered ipsilateral ○ Anterior superior mediastinal nodes are considered regional nodes (level VII) ○ 1st-order nodal drainage is to submandibular nodes (level IB), then to jugulodigastric group (level IIA) at top of internal jugular chain ○ Oral tongue SCCa: 70% have malignant nodes at presentation ○ Retropharyngeal nodes should be evaluated, especially if tumor involves posterior wall of oropharynx ○ ENE is important discriminator and has been added as prognostic variable for regional lymph node metastases in 8th edition of AJCC Staging Manual -Clinical classification of ENE requires unambiguous clinical evidence □ Invasion of skin, infiltration of musculature or adjacent tissue leading to fixation or objective dysfunction of cranial nerve, brachial plexus, sympathetic trunk or phrenic nerve -Current radiologic techniques may suggest presence of ENE and may support clinical findings but is not sufficient alone to designate cENE -ENE can be determined by pathologic classification (pENE) based on microscopic identification of metastatic tumor within node extending through node capsule into adjacent tissue ○ Clinical nodal staging (cN)

Lip and Oral Cavity Carcinoma
-Clinical N1 (cN1) disease indicates metastasis in single ipsilateral node ≤ 3 cm and ENE(-) -Clinical N2 (cN2) includes □ cN2a: Metastasis in single ipsilateral node larger than 3 cm but not larger than 6 cm in greatest dimension and ENE(-) □ cN2b: Metastasis in multiple ipsilateral nodes, none larger than 6 cm in greatest dimension and ENE(-) □ cN2c: Metastasis in bilateral or contralateral lymph nodes, none larger than 6 cm in greatest dimension and ENE(-) -Clinical N3 (cN3) includes □ cN3a: Metastasis in lymph node larger than 6 cm in greatest dimension and ENE(-) □ cN3b: Metastasis in any node(s) and clinically overt ENE(+) • M Staging ○ Distant metastases are present < 10% of time at presentation: Lung > bone >liver ○ CT of chest is commonly performed in addition to CECT of neck to evaluate for pulmonary metastases and also allows for significant osseous coverage of thoracic spine, ribs, sternum, and shoulder girdle ○ PET/CT -PET scan or PET/CT is best overall evaluation for distant metastases -Strong FDG avidity seen in distant metastasis -Sensitivity greatest in metastases with diameter > 1 cm -PET offers major advantage in detecting 2nd primary tumors -Careful attention to artifacts and patterns of physiologic uptake is essential to avoid inaccurate staging

CLINICAL ISSUES Presentation
• OC SCCa usually occurs after 5th decade of life • Strongly associated with tobacco and alcohol use; betel quid chewing is primary epidemiological factor in some parts of world