Impact of Oral Versus Intravenous 5-FU-Based Adjuvant Regimens on Sleep Quality and Depression in Patients With Gastrointestinal Cancers

This is a prospective, non-randomized, single-center observational study designed to investigate the effects of oral versus intravenous (IV) 5-fluorouracil (5-FU)-based adjuvant chemotherapy regimens on sleep quality and depression levels in patients with non-metastatic gastrointestinal system (GIS) cancers. The study will be conducted at the Ankara Etlik City Hospital, Medical Oncology Department. A total of 100 adult patients (≥18 years) who are initiating adjuvant chemotherapy including 5-FU (either oral or IV formulation) for histopathologically confirmed non-metastatic GIS cancers will be included. Eligible patients will be enrolled after providing informed consent. The Pittsburgh Sleep Quality Index (PSQI) and Beck Depression Inventory (BDI), both of which have been validated in Turkish, will be used to assess sleep quality and depression severity. These measurements will be obtained at three time points: (1) baseline (prior to chemotherapy initiation), (2) day 45, and (3) day 90 of treatment. The study aims to detect early psychosocial changes that may occur during chemotherapy, particularly those related to sleep and mood. No changes or interventions will be made to the patients' standard oncological treatment. Patients showing severe sleep disturbances or depressive symptoms during follow-up will be referred to the relevant departments (psychiatry or sleep medicine) for further evaluation and care. The goal of the study is to better understand how the route of 5-FU administration (oral vs. IV) influences sleep patterns and emotional well-being during adjuvant chemotherapy. This could help optimize supportive care strategies and improve the quality of life of patients undergoing treatment for GIS cancers. Data will be analyzed using appropriate statistical tests. Categorical variables will be compared using Chi-square or Fisher's exact test; continuous variables will be compared using Student's t-test or Mann-Whitney U test, depending on distribution. A p-value of \<0.05 will be considered statistically significant.