3.  It is the sixth most common cancer.  Etiology :male > female(both smoker),age >60y old  Geographical : India 40% because tobacco chewers and spicy food.  Predisposing factors : chronic irritation (smoke, spirit,sepsis) but not necessary to lead to cancer.

4. Precancerous lesion :  Erythroplakia  Leukoplakia  Chronic hyperplastic candidiasis  Oral submucous fibrosis  Oral lichen planus  Discoid lupus erythematosis  Discoid keratosis congenital

6. Pathology  lateral margin of anterior 2/3 of the tongue (45-55%),post 1/3 20% and less common site the ventral 9%,dorsl 6%.

7. Grossly malignant ulcer raised,deep,irregular with necrotic floor and everted edge or raised oval white plaque that fungate,central necrosis or hard submucous nodule or diffuse infiltrative(rare).

8. Spread  Direct :to nearby structure (ant 2/3 to lat) and (the post 1/3 totonsil,pharynx,larynx)  Lymphatic: to LN of the neck (ca lat 1/3 to submandibular)and then to deep cervical LN.ca post 1/3 upper deep cervical directly.  Blood : rare mainly in the post 1/3

10. Microscopically  Ant 2/3 well differentiated Scc >95%.  Post 1/3 less differentiated  Bcc and adenocarcinoma of minor salivery gland (rare).

11. Clinical presentation  Symptomless.  Or persistent ulcer >4weeks  Or deep indurated fissure  Or oval raised papillated plaque and white keratin  Or lobulated mass with overlying yellow patch of submucous necrosis.

12. Late stage  Sore tongue the pain first due to infection then due to invasion of lingual n. it may referred to ear.  Salivation due to pain and decrease tongue movement may be blood stained and bad smell.  Enlarged cervical LN (usually painless ).  Complications : -Inhalation of necrotic tissue lead to bronchopneumonia - Cachexia due to dysphagia and pain -Bleeding due to invasion of lingual vessels or ICA in post 1/3 tumor -Asphyxia due to enlarged LN or glottic edema.

14. Investigations  Incisional biopsy for lesion >4weeks UGA or LA  FNAC  MRI or CT to see the invasion

15. Treatment  Lines of treatment :surgery and radiotherapy while chemotherapy as adjuvant in some cases.

16. Surgery  Ca in situ = local excision +1 cm safety margin in extent and 0.5 cm in depth,the defect closed directly or flap from floor of the mouth.  Partial or hemiglossectomy using cutting diathermy or laser. The defect closed by radial flap or rectus abdominis or forehead flap.  Ca post 1/3 = either total or external radiation  If LN metastases so excision of tumor with neck dissection (modified or radical).  Mandible invasion = hemiglossectomy +hemimandibulectomy +neck dissection (commando operation)

17. Radiotherapy Tumor <4 cm equally benefit from RT or surgery

18. Palliative treatment  Radiotherapy  Palliative resection of 1ry to comfort the patient  Analgesia+NG feeding,trachistomy  Chemotherapy  Radiofrequency thermal ablation(minimal invasive therapy)  Gene therapy new treatment gene manipulation to change genetic code in persons cells.