<![CDATA[Diagnostic delay in breast cancer accelerates disease progression and escalates healthcare expenditures under the National Health Insurance (Jaminan Kesehatan Nasional/JKN) program. This study aimed to evaluate the cost-effectiveness of 8-cycle anthracycline, cyclophosphamide-taxane (AC-T) chemotherapy regimen based on diagnostic delay status from the perspective of the Social Security Agency for Health (BPJS Kesehatan). A retrospective cohort study was conducted on 49 breast cancer patients at RSUP Dr. M. Djamil Padang, stratified into neoadjuvant (n = 23) and adjuvant (n = 26) arms, evaluating prospective INA-CBGs claim tariffs and serum CA 15-3 kinetics as a surrogate response biomarker. In the neoadjuvant arm, the non-delay group achieved significant within-group biomarker reduction (p = 0.007; net change: 4.69 vs. 0.31 μ/mL, between-group p = 0.231) and saved IDR 10,125,271 per patient (ICER: -IDR 2,311,706/μ/mL, dominant). In the adjuvant arm, diagnostic delay was associated with post-mastectomy biomarker elevation (-17.25 μ/mL), whereas non-delay saved IDR 10,396,936 per patient (ICER: -IDR 563,520/μ/mL, dominant). Probabilistic sensitivity analysis (10,000 iterations) confirmed 100% stability in Quadrant II of the Cost-Effectiveness Plane across both arms. Prompt diagnosis demonstrates economic dominance by curbing public reimbursement expenditures alongside favorable surrogate biomarker trajectories, supporting the macroeconomic value of strengthening early detection policies.]]>
