This study is a prospective, observational clinical study aimed at evaluating the efficacy of Megestrol Acetate for cachexia in patients with advanced digestive system tumors receiving TKI-based therapy.

Inclusion Criteria:

• Voluntarily sign a written informed consent (ICF).
• Age ≥ 18 years at enrollment.
• Eastern Cooperative Oncology Group (ECOG) performance status of 0-2.
• Life expectancy ≥ 3 months.
• Histologically or cytologically confirmed locally advanced or metastatic digestive system tumors that are not amenable to curative treatment, according to the 8th edition TNM staging classification.
• Not benefiting from local anticancer therapies such as surgery, local ablation, or chemoembolization, and planned to receive TKI-based anticancer treatment, which may be combined with chemotherapy or immunotherapy).
• Meet the diagnostic criteria for pre-cachexia or cachexia (based on Fearon diagnostic criteria).
• Good organ function determined

Exclusion Criteria:

• Gastrointestinal obstruction.
• Anorexia due to difficulty in eating caused by neurosis, mental illness, or pain.
• Comorbidities such as severe cerebrovascular, cardiac, renal, or liver diseases.
• Major surgery or trauma within the last month.
• Allergy to any component of the investigational drug.
• Other conditions deemed unsuitable by the investigator.

Patients with locally advanced or metastatic digestive system tumors