Table 2.

Data variables collected

Patient	Surgical	Tumour
Age Gender BMI ASA score Smoking status Hypertension Diabetes mellitus Coronary artery disease Stroke COPD/Asthma Atrial fibrillation Peripheral arterial disease	Surgical procedure Surgery time Surgical approach Intraoperative blood loss Resective surgery (R0) Adjuvant treatment	TNM (AJCC classification) Grading (G1-G2-G3) Grade of perineural or lymphatic invasion Margins Numbers of lymph nodes studied K-Ras

AJCC, American Joint Committee on Cancer; ASA, American Society of Anesthesiologists physical status classification; BMI, body mass index; COPD, chronic obstructive pulmonary disease; TNM, tumour, node, metastases.

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