A Trial Evaluating Omission of Radiotherapy to Regional Lymphatic's

Inclusion Criteria: 1. Aged 18 or above and less than 70 years 2. Stage pT1-4histological confirmed squamous cell carcinoma of oral cavity undergoing radical excision and ipsilateral/bilateral neck dissection. 3. Patient with high risk features: positive or close (≤ 5mm) margin, presence of LVI or PNI, pT3-4 4. At least one dissected hemi-neck (at least 12 nodes recovered in one dissected hemi-neck) 5. Pathological N0/ N1 neck and high risk features undergoing radiotherapy for HNSCC of the oral cavity 6. Brandwein-Gensler (BG) histological risk assessment in all patients 7. Karnofsky performance score greater or equal 70 8. Ability to complete the MD Anderson Dysphagia Inventory (MDADI) and EORTC quality of life questionnaires English or Hindi Version. 9. Timely delivery of PORT preferable within 6weeks of surgery (upto 1-2 weeks of delay beyond 6 weeks is permissible to accommodate for delayed wound healing or other logistics) 10. Written informed consent for treatment. 11. Available to attend long term follow- up Exclusion Criteria: 1. Non squamous histology 2. Presences of distant metastases 3. pT1-2 disease and no high risk features 4. Pathologically N2/N3 disease. 5. Patients that require re-irradiation for recurrent disease 6. Inadequate neck dissection (less than 12 nodes examined) 7. Primary tumor reaching midline (within 1 cm from midline) and only ipsilateral neck dissection done 8. Initiation of PORT after 8 weeks of radical surgery. 9. Previous radiotherapy to the head and neck region 10. Any invasive malignancy within previous 2 years (other than non melanomatous skin carcinoma or cervical carcinoma in situ). 11. Age \< 18 years or \> 70 years 12. Brandwein-Gensler (BG) histological risk not done