BACKGROUND: Nearly 30% of patients with rectal cancer develop local regrowth after initial clinical complete response managed by watch and wait. These patients might be at higher risk for distant... Show moreBACKGROUND: Nearly 30% of patients with rectal cancer develop local regrowth after initial clinical complete response managed by watch and wait. These patients might be at higher risk for distant metastases.OBJECTIVE: This study aimed to investigate risk factors for distant metastases using time-dependent analyses.DESIGN: Data from an international watch and wait database were retrospectively reviewed. Cox regression analysis was used to determine risk factors for worse distant metastases-free survival. Conditional survival modeling was used to investigate the impact of risk factors on the development of distant metastases.SETTING: Retrospective, multicenter database.PATIENTS: A total of 793 patients (47 institutions) with rectal cancer and clinical complete response to neoadjuvant treatment from the International Watch & Wait Database were included.MAIN OUTCOME MEASURES: Distant metastases-free survival.RESULTS: Of the 793 patients managed with watch and wait (median follow-up 55.2 mo)‚ 85 patients (10.7%) had distant metastases. Fifty-one of 85 patients (60%) had local regrowth at any time. Local regrowth was an independent factor associated with worse distant metastases-free survival in the multivariable model. Using conditional estimates, patients with local regrowth without distant metastases for 5 years (from decision to watch and wait) remained at higher risk for development of distant metastases for 1 subsequent year compared to patients without local regrowth (5-year conditional distant metastases-free survival 94.9% vs 98.4%).LIMITATIONS: Lack of information on adjuvant chemotherapy, salvage surgery for local regrowth, and heterogeneity of individual surveillance/follow-up strategies used may have affected results.CONCLUSIONS: In patients with clinical complete response managed by watch and wait, development of local regrowth at any time is a risk factor for distant metastases. The risk of distant metastases remains higher for 5 years after development of local regrowth. Show less
