Clinicopathological Characteristics With the Status of Mismatch Repair Deficient Invasive Colorectal Cancer With...

Area of Science:

• Gastroenterology
• Oncology
• Pathology

Background:

• Spontaneous regression of endoscopically invasive colorectal cancer (CRC) following biopsy is exceptionally rare.
• Mismatch repair deficiency (MMR-d) is a known factor in some cancers, but its role in CRC regression is not fully understood.

Purpose of the Study:

• To report three novel cases of endoscopically invasive CRC that underwent spontaneous regression after biopsy.
• To review the literature for similar cases of CRC with spontaneous regression, particularly those associated with MMR deficiency.

Main Methods:

• Case series reporting three patients with endoscopically invasive CRC.
• Literature review of studies investigating spontaneous regression of CRC and MMR status.
• Analysis of lesion characteristics, including location and morphology, and MMR status.

Main Results:

• Three patients with endoscopically invasive CRC experienced complete regression of their lesions after biopsy.
• Two of the three patients had tumors with mismatch repair deficiency (MMR-d).
• A literature review identified 12 cases (including these three) of spontaneously regressing CRC, with 11 showing MMR-d and all 12 lesions having a depressed morphology.

Conclusions:

• Spontaneous regression of endoscopically invasive colorectal cancer after biopsy can occur, particularly in cases with MMR deficiency.
• Depressed morphology and proximal colon location appear to be associated with spontaneously regressing CRC.
• Further research is warranted to understand the mechanisms behind MMR-d-associated CRC regression.