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Paper text:
squamous cell carcinoma may arise from dysplastic epithelium or may be entirely independent of it . in the indian population , field cancerization ( slaughters theory )
is found to be extremely prevalent , thereby throwing up fresh challenges for the surgeon .
squamous cell carcinoma primarily spreads via direct invasion and lymphatic routes.[13 ] invasive carcinoma is histologically graded and specified as well - differentiated , moderately well - differentiated , or poorly differentiated types .
the grading of the tumor serves as an important aid to the overall biologic behavior of the tumor .
tumors which more closely resemble their native tissue are considered to be well differentiated ( low grade ) .
this is in contrast to the tumors exhibiting significant cytomorphologic atypia and demonstrating little or no resemblance to native squamous epithelium .
these lesions are considered to be poorly differentiated ( high grade ) and have an increased propensity for regional metastasis and a poorer prognosis .
perineural spread , lymphatic invasion , and tumor extension beyond the lymph node capsule usually point to a poorer prognosis overall .
generally , metastasis from oral squamous cell carcinoma most frequently develops in the ipsilateral cervical lymph nodes .
tumors of the lower lip and floor of mouth may initially involve the submental lymph nodes , but this is relatively rare.[24 ] contralateral or bilateral cervical metastases canal occur especially in tumors of the base of the tongue , in advanced tumors , and in tumors that occur near the midline .
if a tumor perforates the nodal capsule and invades into the surrounding connective tissue , the node will feel fixed and immobile .
as many as 30% of oral cancers have cervical metastases , either palpable or occult , at the time of initial evaluation .
distant metastases are most common in the lungs , prostrate , liver , and bones , but any part of the body may be affected.[14 ] in all cases of suspected oral carcinoma , the neck should be staged prior to biopsy of the primary tumor ; otherwise , regional reactive lymphadenopathy develops subsequent to biopsy , thus hindering the appropriate staging of disease . unfortunately , some patients may have microscopic lymph node disease which may not be detected clinically , and as such , elective neck dissections are sometimes performed to eliminate this eventuality , though the role of positron emission tomography ( pet ) scans has been debated .
the most important indicator of prognosis which serves to establish appropriate treatment modalities is the staging of oral cancer .
staging protocol depends on quantifying three basic clinical features : size of primary tumor , status of regional lymph nodes , and the presence or absence of metastasis .
the american joint committee on cancer ( ajcc ) utilizes the tumor , lymph node , and metastases ( tnm ) classification system for their staging protocol . at our center
, we also incorporate the guidelines for treatment of oral cancer , as determined by tata memorial cancer centre in mumbai .
although surgery is the primary mode of treating squamous cell carcinoma of the head and neck , radiotherapy and chemotherapy , either alone or in combination , play important roles .
the goal of surgery is to eradicate all visibly gross disease and at the same time provide adequate disease free margins to counter the risk of microscopic metastasis [ figures 1 and 2 ] .
resected primary with free margins to limit microscopic disease spread the disease ( gross ) free neck with preservation of internal jugular vein , sternocleidomastoid muscle and spinal accessory nerve in our center , the neck is cleared as per the regional cancer centre , thiruvanthapuram protocol , where the continuity of the specimen may be sacrificed to preserve all the vital structures , similar to functional neck dissection , but all the gross disease with margins of a minimum of 2 cm are carefully removed .
dissections are performed for patients who have positive lymph node involvement at the initial workup stage and entails complete removal of all lymphatic tissue from the neck ( levels i  iv ) , though elective dissections are performed for all patients with tumor size more than 1.5 cm regardless of neck node involvement due to the poor patient compliance regarding follow - up in our center .
the classic radical neck dissection includes comprehensive node dissection with removal of the sternocleidomastoid muscle , internal jugular vein , and spinal accessory nerve .
modified radical ( functional ) neck dissection was developed to diminish the morbidity by removing all cervical nodes but preserving important anatomical structures .
selective neck dissections involve the removal of lymph node groups at highest risk of containing metastasis from a primary tumor .
radiotherapy is primarily used as postoperative treatment for cases in which resection margins are not free of tumor , or there is surgical inaccessibility , or there has been perineural growth and bone invasion .
all cases in our center are sent for a radiotherapy reference prior to and after surgery .
chemotherapy may also be given as palliative treatment to patients with locally recurrent disease , which can not be cured with surgery or radiotherapy , or to patients with distant metastases.[13 ]
successive treatment of squamous cell carcinoma of the oral cavity involves a combination of addressing the anatomic site of the primary cancer , status of the neck , anticipated functional and cosmetic results , anticipated patient compliance , and the overall medical status of the patient .
we feel that the ability to control oral cancer depends upon two principles : prevention and early detection . therefore , with squamous cell carcinoma being the most common head and neck malignancy , it is mandatory that all dental professionals and facio - maxillary surgeons examine all patients with precancerous disease and early disease , with an emphasis on maximum patient education .
in the indian subcontinent , the incidence of squamous cell carcinoma of the oral cavity has been constantly increasing despite the improvement in the awareness about squamous cell carcinoma . 
 the patients generally report to us in the period in which the tumor would have undergone metastasis . 
 this article highlights about the grading , staging , and decision - making regarding the surgical management of squamous cell carcinoma of the oral cavity . 
 the article also stresses upon the early detection of the lesion by the practitioner for a definitive successful surgical treatment of the patient .