This literature review focuses on the degree of malnutrition in cancer patients using malnutrition screening tools and the relation between malnutrition and cancer-related complications. The review includes the Patient-Generated Subjective Global Assessment, Malnutrition Screening Tool, and Malnutrition Universal Screening Tool. The effectiveness of PG-SGA and MUST is also compared. The study concludes that PG-SGA is a reliable screening tool for determining malnutrition in cancer patients.