Evaluation of the Efficacy and Safety of Megestrol Acetate in Preventing Nausea and Vomiting Induced by Highly Emetogenic Chemotherapy

1. Age ≥ 18 years, regardless of sex

2. Histologically or cytologically confirmed lung cancer

3. Expected survival ≥ 3 months

4. Female subjects of childbearing potential must have negative serum pregnancy test within 72 hours prior to randomization and must be non-lactating

5. Capable of comprehending and willingly providing signed informed consent form (ICF), and adhering to study requirements/restrictions Exclusion Criteria

1. Received or scheduled to receive concurrent radiotherapy within 7 days prior to enrollment through Day 1-8 of treatment 2. Systemic corticosteroid therapy or sedating antihistamines within 7 days prior to enrollment 3. Poorly controlled serous cavity effusions (pleural/peritoneal/pericardial) 4. Severe cardiovascular diseases within 3 months prior to enrollment 5. Participation in other clinical trials within 30 days prior to enrollment