Risks of Organ Preservation in Rectal Cancer: Data From Two International Registries on Rectal Cancer.

Area of Science:

• Colorectal cancer management
• Oncology
• Surgical oncology

Background:

• Organ preservation via Watch and Wait (WW) is an alternative to total mesorectal excision (TME) for rectal cancer patients achieving clinical complete response (cCR) after neoadjuvant therapy.
• Local regrowth (LR) occurs in nearly 30% of these patients, potentially increasing the risk of distant metastases (DM) even with salvage resection.

Purpose of the Study:

• To compare the risk of distant metastases (DM) in patients with local regrowth (LR) after Watch and Wait (WW) versus patients with near-complete pathologic response (nPCR) managed by total mesorectal excision (TME).

Main Methods:

• Retrospective comparison of patients from the International Watch & Wait Database (IWWD) with LR after WW and patients from the VIKINGO project with nPCR after TME.
• Primary endpoint: 3-year distant metastasis-free survival.
• Secondary endpoint: identification of risk factors for DM.

Main Results:

• Distant metastasis (DM) rates were significantly higher in the LR group (22.8%) compared to the nPCR group (10.2%).
• Independent risk factors for DM included LR, ypT3-4, and ypN+ status.
• 3-year DM-free survival was significantly worse for patients with LR (75%) versus nPCR (87%).

Conclusions:

• Patients with local regrowth (LR) after Watch and Wait (WW) demonstrate a higher risk of subsequent distant metastases (DM) compared to those managed with total mesorectal excision (TME) for near-complete pathologic response.
• Leaving the primary tumor in situ until LR develops may lead to poorer oncologic outcomes.