Neutrophil-to-Lymphocyte Ratio and MUST-Defined Nutritional Risk as Independent Correlates of Domain-Specific Quality of Life in Cancer Patients Receiving Chemotherapy

Background: Nutritional deterioration and systemic inflammation are prevalent in cancer patients undergoing chemotherapy and may independently impair health-related quality of life (QoL). Yet their simultaneous, domain-specific contributions to QoL remain poorly characterized, particularly in Middle Eastern populations. Methods: This cross-sectional study included adult cancer patients receiving chemotherapy. Medical records were used to collect clinical and laboratory data. Structured interviews were conducted to assess nutritional status using the Malnutrition Universal Screening Tool (MUST) and quality of life using the EORTC QLQ-C30 questionnaire. The NLR was calculated as an indicator of systemic inflammation. Multiple linear regression models, adjusted for age, sex, cancer site, stage, and treatment cycle, were used to examine independent associations with QoL domains. Results: Nearly 60% of patients were at a medium-to-high malnutrition risk and 27.1% exhibited high systemic inflammation (NLR > 3). The NLR was significantly associated with greater dyspnea (B = 28.4, p = 0.001), and the MUST was significantly associated with greater appetite loss (B = 17.0, p = 0.001). Additional significant associations included the NLR with poorer physical functioning (p = 0.009) and role functioning (p = 0.012), and the MUST with nausea and vomiting (p = 0.039). In the multivariate analysis, the NLR showed a statistically significant overall effect on the QoL profile (p = 0.007), while the MUST did not (p = 0.281), consistent with its more domain-specific pattern. Conclusions: This cross-sectional study suggests that systemic inflammation and nutritional risk are associated with domain-specific quality of life among cancer patients receiving chemotherapy. The NLR and MUST may represent accessible, complementary indicators of patient vulnerability and supportive care needs. Prospective multi-center studies are warranted to validate these associations and determine their clinical utility in supportive oncology practice.