Comprehensive assessment of nutritional status in colorectal cancer patients before surgery: a cross-sectional study

Background Malnutrition is a prevalent and clinically significant problem among patients with cancer, affecting 20–70% of cases, with the highest rates in gastrointestinal malignancies. In colorectal cancer (CRC), preoperative malnutrition is particularly concerning, as it increases postoperative complications, prolongs hospital stay, impairs treatment tolerance, elevates healthcare costs, and reduces survival. Tumor-related inflammation, metabolic stress, and surgical trauma further exacerbate nutritional deterioration, making early identification essential. There are few studies that have exclusively examined the nutritional status before surgery in CRC patients, specifically in Iran. Given the importance of nutrition screening and the comprehensive evaluation of malnutrition in patients at risk of malnutrition before surgery, this study aimed to evaluate the comprehensive nutritional assessment of these patients before surgery. Methods This cross-sectional study was conducted from October 2023 to January 2025 at the surgical department of Ghaem Hospital, Mashhad, Iran. Hospitalized patients with confirmed CRC were included. Demographic and disease-related information was collected. Nutritional status was assessed using the patient-generated subjective global assessment (PG-SGA). Anthropometric measurements, body composition analysis, dietary intake evaluation, nutrition impact symptoms, handgrip strength, and laboratory tests were assessed. Logistic regression was used to identify independent factors associated with critical nutritional risk (PG-SGA score ≥ 9). Results A total of 105 patients (mean age 57.5 ± 13.3 years) were included. 54.3% had moderate-to-severe malnutrition (PG-SGA Category B or C), including 21.9% with severe malnutrition (Category C), and 40% had critical nutritional risk (PG-SGA score ≥ 9). Low muscle strength was observed in 78.1%, and reduced muscle mass in 26.7%. Common symptoms included abdominal pain, indigestion, bloating, constipation, and anorexia. Inadequate energy and protein intake were reported in 48.6% and 83.8% of patients, respectively. Older age (> 65 years), low economic status, cancer unawareness, tumor pathology, anemia, lower serum albumin, and insufficient energy and protein intake were associated with higher PG-SGA scores ( p < 0.05). PG-SGA scores negatively correlated with BMI, Karnofsky performance status, mid-upper arm circumference, total body water, and fat-free mass index ( p < 0.01). FFMI (fat-free mass index), serum albumin, and non-adenocarcinoma pathology ( n = 5; imprecise estimate) were independently associated with critical nutritional risk (PG-SGA ≥ 9) in the exploratory multivariable logistic regression analysis. Conclusion A substantial proportion of patients awaiting CRC surgery had moderate-to-severe malnutrition or critical nutritional risk. These findings highlight the importance of timely nutrition screening to identify at-risk patients, followed by comprehensive nutrition assessment to guide individualized interventions, optimize preoperative care, and improve clinical and functional outcomes.