The following is the summary of “Risk of Distant Metastases in Patients With Clinical Complete Response Managed by Watch and Wait After Neoadjuvant Therapy for Rectal Cancer: The Influence of Local Regrowth in the International Watch and Wait Database” published in January 2023 issue of Diseases of the Colon & Rectum by Fernandez, et al.

Local regrowth of rectal cancer occurs in about 30% of patients who have achieved clinical full response and are being followed with observation. It’s possible that these patients are more likely to develop distant metastases. The purpose of this research was to use temporal analyses to identify potential risk factors for distant metastases. In this study’s design, information from a global “watch and wait” database was analyzed retrospectively. Factors associated with decreased time without developing distant metastases were identified using Cox regression analysis. The effect of potential risk variables on the appearance of distant metastases was studied using conditional survival modeling. Multi-center, retrospective database. About 793 patients (from 47 different institutions) with rectal cancer who had a clinical full response to neoadjuvant treatment were included in the study.

Survival free of distant metastases is the primary endpoint. The results showed that 85 patients (10.7%) with distant metastases were among the 793 patients who were managed with the watch and wait (median follow-up 55.2 months). About 60% of the patients (51 out of 85) saw some local regrowth. In the multivariate analysis, local regrowth stood out as an independent predictor that predicted a lower risk of dying from distant metastases. When comparing patients with and without local regrowth, the conditional estimates show that patients with local regrowth have a lower 5-year conditional distant metastases-free survival (94.9% vs. 98.4%) and are at a higher risk for developing distant metastases in the following year (by 1 percentage point).

Results may have been impacted by the variability of individual surveillance/follow-up strategies used and the lack of information on adjuvant chemotherapy, salvage surgery for local regrowth, and other factors. It is concluded that the occurrence of local regrowth at any time is a risk factor for distant metastases in patients with clinical full response managed by watch and wait. For 5 years after local regrowth appears, the risk of distant metastases is still elevated.