<prompt> A 45 old chronic tobacco chewer presents with the chief complaints of a mass in the oral cavity of 1.5 cm with a single lymph node on ipsilateral neck. The stage of the tumor is -T1N3T3N1T2N2T1N1  <response>: Ans. is d i.e., T1N1 o Heres the TNM staging for Oral cavity carcinoma according to TNM 7th editionPrimary 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 Regional lymphadenopathyNXUnable to assess regional lymph nodesN0No evidence of regional metastasisN1Metastasis in a single ipsilateral lymph node, 3 cm or less in greatest dimensionN2aMetastasis in a single ipsilateral lymph node, 3 cm and 6 cmN2bMetastasis in a multiple ipsilateral lymph nodes, all nodes 6 cmN2cMetastasis in a bilateral or contralateral lymph nodes, all nodes 6 cmN3Metastasis in a lymph node 6 cm in greatest dimension 