Colorectal cancer is a common and often fatal malignancy, and predicting survival can help guide treatment decisions. This study aimed to investigate the impact of clinicopathological characteristics and nutritional status on survival in patients with metastatic colorectal cancer receiving first-line treatment with 5-fluorouracil in combination with monoclonal antibodies (bevacizumab, cetuximab, or panitumumab). This prospective, non-interventional, observational, single-center study included 150 adult patients with metastatic colorectal cancer undergoing first-line therapy. Demographic data, cancer-related characteristics, laboratory parameters, and nutritional status assessed via the Mini Nutritional Assessment-Short Form were recorded prior to treatment initiation. Mini Nutritional Assessment-Short Form scores of 12-14, 8-11, and 0-7 were used to define normal nutritional status, risk of malnutrition, and malnutrition, respectively. The mean ages of patients without and with malnutrition were 60±11 and 62±11 years, respectively. Median progression-free survival and overall survival were 12 and 22 months, respectively. Multivariate analysis identified alcohol history (HR=2.83; 95%CI 1.27-6.34; p=0.011) and Mini Nutritional Assessment-Short Form≤7 (HR=1.93; 95%CI 1.09-3.45; p=0.025) as significant predictors of shorter progression-free survival. Mini Nutritional Assessment-Short Form ≤7 (HR=2.96; 95%CI 1.80-4.89; p<0.001) was also significantly associated with decreased overall survival. Among patients with metastatic colorectal cancer receiving first-line therapy, malnutrition (Mini Nutritional Assessment-Short Form≤7) and a history of alcohol use were associated with poorer survival outcomes. These findings underscore the importance of routine nutritional assessment and support the need for further prospective multicenter studies to validate these results.

Background: The aim of this study is to determine the prevalence of malnutrition, frailty, and cachexia in patients with different cancer subtypes undergoing oncological treatment using various screening scales and to evaluate the distribution of these conditions by geriatric age groups. Methods: This cross-sectional study included 4595 patients with different cancer subtypes undergoing oncological treatment. Nutritional status was assessed using the Mini Nutritional Assessment—Short (MNA-S) form; frailty was evaluated with the Fatigue, Resistance, Ambulation, Illnesses, and Loss of weight (FRAIL) scale; and cachexia was determined based on >5% weight loss in the last 6 months or a body mass index (BMI) < 20 kg/m², together with an additional >2% weight loss. Patients were divided into two groups by geriatric age. Results: A total of 36% of the patients included in the study were geriatric (≥65 years old). The prevalence of malnutrition, frailty, and cachexia in the general population was determined to be 40%, 45%, and 44%, respectively. All three conditions were found to be statistically significantly more prevalent in the geriatric age group (p < 0.001 for all comparisons). Conclusions: It was determined that the prevalence of malnutrition, frailty, and cachexia was high in cancer patients receiving systemic oncological treatments including chemotherapy, hormonal therapy, targeted therapy, and immunotherapy; these syndromes are significantly more common, particularly in the geriatric patient group.