Hospital Profitability of Robot-Assisted Gastrointestinal Cancer Surgery in Japan Under the National Fee Schedule: A Surgical Program Model with Required-Cut and Isoprofit Maps

Background/Objectives: Robot-assisted gastrointestinal (GI) cancer surgery has expanded in Japan since national reimbursement in 2018, yet hospital profitability remains uncertain because of capital, maintenance, and consumable costs. We examined whether a program-level volume threshold for profitability exists under Japan’s fee schedule and quantified actionable improvement targets. Methods: We developed a hospital-perspective, model-based economic evaluation (index admission to 30 days; 2025 Japanese yen (JPY)) comparing robot-assisted surgery (RAS) with conventional laparoscopic surgery (CLS) under Japan’s fee schedule (one point = ¥10) for gastrectomy, colectomy, rectal resection, and pancreatoduodenectomy. Case-level contribution margin differentials (ΔCM) were defined as the revenue differential minus the consumables differential and additional operating room (OR) time costs, plus savings from reduced length of stay (LOS), and were aggregated to annual program profit (Π) after fixed costs and platform sharing. Primary outputs were allowable consumables, required cut (%), and isoprofit contours. Uncertainty was assessed using 50,000-iteration probabilistic sensitivity analysis (PSA), one-way sensitivity analysis (OWSA), and learning-curve scenarios in line with Consolidated Health Economic Evaluation Reporting Standards (CHEERS) 2022. Results: In the base case, ΔCM was predominantly ≤0 for colon, rectum, and pancreatoduodenectomy; therefore, when the case-mix-weighted mean ΔCM was ≤0, increasing volume could not achieve breakeven and instead increased losses. Each 10 min reduction in OR time increased allowable consumables by ¥15,000, and each bed-day reduction increased it by ¥30,000. These required-cut and isoprofit maps provide actionable targets for cost negotiation, operational improvement, and platform sharing. Conclusions: Volume expansion alone rarely yields profitability; coordinated reductions in consumables, OR time, and LOS, together with platform sharing, are required.