Light and shadow of Watch-and-wait strategy in rectal cancer. Oncological result, clinical outcomes after salvage surgery and cost effectiveness analysis. Experience of a single centre.

Background: W atch and wait strategy is a potential option for patients with rectal cancer that obtain a complete clinic response after neoadjuvant therapy. The aim of this study is to analyse long-term oncological outcomes and perform a cost-effectiveness analysis in patients undergoing Watch and wait strategy for rectal cancer. Material and Methods: Data of patients treated with Watch and Wait strategy were prospectively collected from January 2015 to January 2020. A control group was created, matched 1:1 from a pool of 480 patients undergoing total mesorectal excision . An independent company carried out the financial analysis. Clinical and oncological outcomes were analysed in both groups. Outcome parameters included surgical and follow-up costs, quality-adjusted life years (QALYs) and the incremental cost per QALY gained or the incremental cost-effectiveness ratio (ICER). Results: 40 patients were included in the WW group and 40 patients in the surgical group. During a median follow-up period of 36 months, metastasis-free survival (MFS) and overall survival (OS) were similar in the two groups. In the WW group, 9 (22%)local regrowthwere detected in the first two years. The permanent stoma rate was slightly higher after salvage surgery in the WW group compared to the upfront surgical group (48.5% vs 20%, p<0.01). The cost-effectiveness analysis was slightly better for the WW group especially in low rectal cancer with respect to medium-high rectal cancer (ICER= -108642.1 vs ICER= -42423). Conclusions : WW strategy in locally advanced rectal cancer offers similar oncological outcomes respect to the surgical group and excellent result in quality of life and cost, especially in low rectal cancer. Nonetheless salvage surgery may by characterized by desfavorable functional outcome. Therefore a careful selection of patients is mandatory.