Primary Objective: To evaluate the effect of nanocrystalline megestrol acetate versus placebo on body weight and appetite in patients with unresectable hepatocellular carcinoma receiving TACE combined with targeted and immunotherapy.Secondary Objectives: To evaluate the effect of nanocrystalline megestrol acetate versus placebo on quality of life, inflammatory markers, nutritional indicators, and psychological stress in patients with unresectable hepatocellular carcinoma receiving TACE combined with targeted and immunotherapy.Exploratory Objective: To explore the impact of nanocrystalline megestrol acetate versus placebo on survival benefit in patients with unresectable hepatocellular carcinoma receiving TACE combined with targeted and immunotherapy.