RESUMO
Cancer patients are particularly susceptible to undernourishment so associated weight loss is frequent. Approximately 15% of patients lose >10% of their usual body weight, 40-80% become undernourished, and about 20% die as a result. Well-nourished patients have a higher survival rate when compared with patients at risk of undernourishment (19.9 vs. 3.7 months); hence, nutritional intervention is pivotal. Undernourishment negatively influences the patient's prognosis, and its prevalence depends on the tumor type and location, disease stage, treatment, and the applied nutritional evaluation tool. During abdominopelvic radiotherapy, up to 90% of patients experience symptoms of varying severity; weight loss during radiotherapy is an early indicator of nutritional deterioration, and he the use of radiation is associated with a higher likelihood of undernourishment. In patients with gynecological malignancies, 12.5-54% are malnourished before receiving oncological treatment, worsening after treatment in 35.8-82% of cases. There is also deterioration of the nutritional status in patients with colorectal cancer once pelvic radiotherapy is initiated, whereby 50% of cases are malnourished at the beginning of treatment, and 66.7% are so when it ends. Although there are notable differences in the impact of radiotherapy on weight according to the radiated region, 88% patients receiving abdominal radiotherapy were found to lose weight compared to 38% of patients whose treatment was limited to the pelvis.