To review the risk of local recurrence and impact of salvage therapy after Watch and Wait for rectal cancer with complete clinical response (cCR) after chemoradiation therapy (CRT).

Patients with cT2-4N0-2M0 distal rectal cancer treated with CRT (50.4-54 Gy + 5-fluorouracil-based chemotherapy) and cCR at 8 weeks were included. Patients with cCR were enrolled in a strict follow-up program with no immediate surgery (Watch and Wait). Local recurrence-free survival was compared while taking into account Watch and Wait strategy alone and Watch and Wait plus salvage.

90 of 183 patients experienced cCR at initial assessment after CRT (49%). When early tumor regrowths (up to and including the initial 12 months of follow-up) and late recurrences were considered together, 28 patients (31%) experienced local recurrence (median follow-up time, 60 months). Of those, 26 patients underwent salvage therapy, and 2 patients were not amenable to salvage. In 4 patients, local re-recurrence developed after Watch and Wait plus salvage. The overall salvage rate for local recurrence was 93%. Local recurrence-free survival at 5 years was 69% (all local recurrences) and 94% (after salvage procedures). Thirteen patients (14%) experienced systemic recurrence. The 5-year cancer-specific overall survival and disease-free survival for all patients (including all recurrences) were 91% and 68%, respectively.

Local recurrence may develop in 31% of patients with initial cCR when early regrowths (≤ 12 months) and late recurrences are grouped together. More than half of these recurrences develop within 12 months of follow-up. Salvage therapy is possible in ≥ 90% of recurrences, leading to 94% local disease control, with 78% organ preservation.