Stage II colon cancer.

Area of Science:

• Oncology
• Gastroenterology
• Cancer Biomarkers

Background:

• Colorectal cancer (CRC) is a leading cause of cancer worldwide, with Stage II representing approximately 25% of cases.
• Stage II CRC, characterized by local tumor invasion without lymph node or distant metastasis, exhibits significant biological and prognostic heterogeneity.
• Current adjuvant 5-fluorouracil (FU) chemotherapy offers a modest 3-4% reduction in recurrence risk for Stage II CRC, benefiting only a subset of patients.

Purpose of the Study:

• To identify reliable biomarkers for predicting adjuvant chemotherapy benefit in Stage II colorectal cancer.
• To differentiate patient subgroups within Stage II CRC based on prognosis and treatment response.
• To refine treatment decisions for Stage II CRC by integrating molecular and clinical data.

Main Methods:

• Analysis of clinicopathological features, including tumor stage (T3) and microsatellite instability (MSI) status.
• Evaluation of gene expression profiles to derive a validated recurrence score.
• Comparison of prognostic information provided by molecular biomarkers versus conventional features.

Main Results:

• Patients with T3 primary tumors and high microsatellite instability (MSI-High) demonstrate an excellent prognosis, negating the need for adjuvant chemotherapy.
• For microsatellite-stable (MSS) Stage II CRC, a recurrence score derived from gene expression provides superior prognostic accuracy compared to traditional clinicopathological factors.
• The recurrence score effectively stratifies patients, aiding in the selection of those likely to benefit from adjuvant chemotherapy.

Conclusions:

• Microsatellite instability testing is crucial for identifying Stage II CRC patients who can safely forgo adjuvant chemotherapy.
• Gene expression-based recurrence scores offer a more precise tool for personalizing adjuvant chemotherapy decisions in Stage II CRC.
• Integrating MSI status and recurrence scores optimizes treatment strategies, improving outcomes and avoiding unnecessary toxicity in Stage II colorectal cancer.