Outline the principle of personalisation of treatment of oesophageal malignancy based on tumor staging. Stage 0 Principle: Early-stage cancer confined to the inner most layer of the oesophagus. Treatment: Endoscopic therapies. E.g. endoscopic mucosal resection (EMR) and radiofrequency ablation (RFA). Rationale: Minimally invasive procedures -> effective at removing or destroying the abnormal cells with minimal impact on the surrounding tissues. Stage 1 T1, N0 and M0. Principle: Tumor invades the submucosa but NO lymph node involvement or metastasis. Treatment: Endoscopic resection or esophagectomy for more extensive lesions. Rationale: Early surgical intervention. Achieves high cure rate with limited spreads. Stage 2 T2-T3, N0-N1, M0 . Principle: Tumor invades the muscularis propria or adventitia, with possible regional lymph node involvement. Treatment: Neoadjuvant chemoradiotherapy followed by esophagectomy. Rationale: Preoperative therapy can regress the tumor. Makes the surgery more effective. Reduces the risk of recurrence. Stage 3 T3-T4, N1-N2, M0 . Principle: Tumor invades nearby structures or has significant lymph node involvement. Treatment: Combined modality therapy including chemoradiotherapy followed by surgery, or definitive chemoradiotherapy for non-surgical candidates. Rationale: Aggressive treatment is necessary to control local and regional disease. Improves survival. Stage 4 Principle: Distant metastasis present. Treatment: Palliative care focusing on symptom relief and quality of life. Includes chemotherapy, targeted and supportive care. Rationale: Aims to manage symptoms. Aims to prolong survival. Aims to maintain quality of life rather than cure.