Cost-Effectiveness and Quality-Adjusted Survival of Watch and Wait After Complete Response to Chemoradiotherapy for Rectal Cancer

Abstract

Neoadjuvant chemoradiotherapy (CRT) followed by total mesorectal excision (TME) is the standard treatment for locally advanced rectal cancer. There is interest in deescalating local therapy after a clinical complete response to CRT. We hypothesized that a watch-and-wait (WW) strategy offers comparable cancer-specific survival, superior quality-adjusted survival, and reduced cost compared with upfront TME. We developed a decision-analytic model to compare WW, low anterior resection, and abdominoperineal resection for patients achieving a clinical complete response to CRT. Rates of local regrowth, pelvic recurrence, and distant metastasis were derived from series comparing WW with TME after pathologic complete response. Lifetime incremental costs and quality-adjusted life-years (QALY) were calculated between strategies, and sensitivity analyses were performed to study model uncertainty. The base case 5-year cancer-specific survival was 93.5% (95% confidence interval [CI] = 91.5% to 94.9%) on a WW program compared with 95.9% (95% CI = 93.6% to 97.4%) after upfront TME. WW was dominant relative to low anterior resection, with cost savings of $28 500 (95% CI = $22 200 to $39 000) and incremental QALY of 0.527 (95% CI = 0.138 to 1.125). WW was also dominant relative to abdominoperineal resection, with a cost savings of $32 100 (95% CI = $21 800 to $49 200) and incremental QALY of 0.601 (95% CI = 0.213 to 1.208). WW remained dominant in sensitivity analysis unless the rate of surgical salvage fell to 73.0%. Using current multi-institutional recurrence estimates, we observed comparable cancer-specific survival, superior quality-adjusted survival, and decreased costs with WW compared with upfront TME. Upfront TME was preferred when surgical salvage rates were low.