We sought to evaluate the evolution of the nutritional status of patients with advanced cancer of the upper aerodigestive tract undergoing surgical treatment (SURG) or organ preservation protocol (OP). Evaluations were conducted at the beginning and end of treatment, including weight, body composition and Patient-Generated Subjective Global Assessment (PG-SGA). Each group was comprised of 29 patients. Initially, malnutrition rates were 65.5% and 51.7% in the SURG and OP groups, respectively. At the end, the values went to 55.1% in SURG and 79.3% in OP. In the OP, there was a reduction in weight (P = 0.001), fat mass (P = 0.006), fat free mass (P = 0.002), and muscle mass (P = 0.005) and an increase in scores of the PG-SGA (P = 0.008). The same was not observed in SURG, except for the weight decrease (P = 0.025). Malnutrition was prevalent in both treatment groups and patients in OP were at greater risk of nutritional decline.