Risk of Metachronous Colorectal Cancer after Segmental or Extended Resection in Patients with Lynch Syndrome

Area of Science:

• Oncology
• Genetics
• Surgical Oncology

Background:

• Lynch syndrome (LS) patients with colorectal cancer (CRC) traditionally undergo extended colectomy.
• This recommendation is debated due to morbidity, lack of survival benefit, and immunotherapy advancements.

Purpose of the Study:

• To evaluate the impact of colectomy extent on metachronous CRC and survival in LS patients.
• To compare outcomes between segmental and extended resections based on LS gene risk.

Main Methods:

• A prospective database of LS patients diagnosed with CRC (1969-2024) was analyzed.
• Rates of metachronous CRC and 10-year overall survival were compared between resection types.

Main Results:

• Metachronous CRC occurred in 20% of patients; rates were higher in high-risk LS gene variants (MLH1, MSH2).
• Extended resection significantly reduced metachronous CRC in high-risk variants (6% vs. 30%) but not low-risk variants.
• Ten-year overall survival was similar across segmental (89%) and extended (96%) resections.

Conclusions:

• Extended colectomy reduces metachronous CRC risk in high-risk LS patients but does not improve overall survival.
• Segmental resection with surveillance is a reasonable alternative, allowing for future interventions like repeat surgery or immunotherapy.