Risk of distant metastasis after local excision for near-complete response versus salvage surgery for local regrowth in rectal cancer: Results from an international registry

Abstract

Aim: Watch and Wait (WW) strategy is currently used for mid/low rectal adenocarcinoma after neoadjuvant treatment (NAT). Local regrowth (LR) is a well-known risk, but its impact on distant metastasis (DM) is increasingly debated. This study aimed to assess the rate of DM after local excision (LE) for near-complete clinical response (ncCR) at restaging versus salvage surgery for regrowth following WW.

Method: Retrospective analysis of DM rates from a prospective international registry, comparing patients with ncCR after NAT who underwent LE and patients with initial complete clinical response (cCR) and WW strategy, who underwent salvage surgery for regrowth. The primary endpoint was the 5-year distant metastasis-free survival (5y-DMFS). Univariate/Multivariate analysis were performed to identify risk factors of DM.

Results: Among 138 patients included, 59 had LE for ncCR and 79 had salvage surgery after regrowth including TME (n = 23), APR (n = 30) and LE (n = 26). The 5y-DMFS was lower in patients with surgery at regrowth, 71 % vs. 93 % (p = 0.006). LR was the only independent risk factor associated with DM (OR:3.89; 95 % CI:1.34-11.25; p = 0.012). When only patients managed by salvage LE for LR are considered, 5y-DMFS was equivalent to LE at restaging (87 vs. 93; p = 0.442).

Conclusion: Patients with rectal cancer undergoing LE for ncCR after NAT have a significantly lower rate of DM compared to patients undergoing salvage surgery after LR within WW approach. Patients managed by LE for regrowth may represent a distinct subgroup where the risk of subsequent DM is equivalent to patients managed by LE at restage.