Watch-And-Wait Policy Versus Robotic Resection In Locally Advanced Rectal Cancer Patients After Clinical Complete Response Following Chemoradiotherapy: A Cost-Effectiveness Study (Reccoste).

e19374 Background: Chemoradiotheray (CR) followed by standard Surgical Resection (SR) is the standard treatment for distal locally-advanced rectal cancer (LARC) patients after a clinical compete response (cCR). Some novel approach suggested better functional results using robotic rectal resection (RRR) or avoiding surgical procedure, called Watch and Wait (WW) strategy. Methods: A Markov model-based, cost-utility analysis estimating mean costs and QALYs per patient was performed to compare SR, RRR and WW strategies for patients achieving a cCR to CRT. Rates of local regrowth, recurrence and distant metastasis were derived from series comparing WW to SR and from our previous comparative study of RRR versus SR. Lifetime incremental cost-utility ratio was calculated between strategies, and sensitivity analysis were performed to study model uncertainly. A willingness-to-pay of 30.000 per Quality Adjusted-Life Year (QALY) was used as a threshold to determine the most cost-effective treatment. Results: The base case 15-years cancer-specific survival was 93.5% (95% confidence interval [CI] 91.5-94.9] on a WW program, compared to 95.9% [95%CI 93.6-97.7] after RRR. WW was dominant relative to RRR with cost savings of $48,566.58 (95%CI $47,635.77 - $49,497.39 ) and incremental QALY of 7.47 (95%CI 1.46 – 7.48). WW was also dominant relative to LRR, with cost savings of $48,764.49 (95%CI $47,768.49 - $49,760.48 ) and incremental QALY of 7.44 (95%CI 7,43 – 7.45). WW remained dominant in sensitivity analysis unless the rate of SR fell to 73.0%). Conclusions: This study provides data of cost-effectiveness differences between SR, RRR, WW approaches in LARC after cCR, showing a benefit for WW.