<prompt> T3 Stage in oral cancer is -Tumour 2cm in greatest dimensionTumour 4cmin greatest dimensionTumour 6cmin greatest dimensionTumour 8cmin greatest dimension  <response>: Ans. is b i.e., Tumour 4cmin greatest dimension Primary tumor staging of oral cavity carcinomaT0No evidence of primary tumorT1Tumor is 2 cm in greatest dimensionT2Tumor is 2 cm and 4 cm in greatest dimensionT3Tumor 4 cm in greatest dimensionT4a lipPrimary tumor invading cortical bone, inferior alveolar nerve, floor of mouth, or skin of face e.g., nose or chinT4a oral cavityTumor invades adjacent structures e.g., cortical bone, into deep tongue musculature, maxillary sinus or skin of faceT4b lip oralTumor invades masticator space, pterygoid plates, or skull base andor encases the internal carotid artery 