A 65-year-old woman with resected stage II colorectal cancer (T3N0M0) is being counseled about adjuvant therapy. She has no contraindications to chemotherapy. Which is the preferred adjuvant regimen?

Explanation

## Adjuvant Chemotherapy for Stage II Colorectal Cancer **Key Point:** FOLFOX is the preferred adjuvant regimen for stage II colorectal cancer with high-risk features (T3N0 or T4 tumors, poor differentiation, lymphovascular invasion, or microsatellite stability). ### Stage II Risk Stratification **High-Risk Stage II** (like this patient's T3N0): - Tumor depth ≥T3 - Poor histologic differentiation - Lymphovascular or perineural invasion - Inadequate lymph node sampling (<12 nodes) - Microsatellite stable (MSS) or proficient mismatch repair (pMMR) **Benefit of FOLFOX in High-Risk Stage II:** - Reduces recurrence risk by ~20% - Improves disease-free survival (DFS) by 3–5 years - Absolute benefit: ~3–5% at 5 years - Supported by ASCO, ESMO, and NCCN guidelines ### Adjuvant Regimen Comparison | Regimen | Indication | DFS Benefit | Toxicity | |---------|-----------|-------------|----------| | **5-FU monotherapy** | Obsolete; rarely used | Minimal | Low | | **5-FU/LV** | Stage III; low-risk stage II | Modest | Low | | **FOLFOX** | High-risk stage II; all stage III | Superior | Moderate (neuropathy, myelosuppression) | | **Bevacizumab + chemo** | Not standard adjuvant; mainly metastatic disease | Not established | Higher | **High-Yield:** Stage II T3N0 is considered "high-risk" and warrants FOLFOX, not just 5-FU/LV. The oxaliplatin component is critical for improved outcomes. **Mnemonic: FOLFOX for HIGH-RISK Stage II** — **F**luorouracil, **O**xaliplatin, **L**eucovorin for tumors with **H**igh-risk features (T3/T4, poor grade, LVI). **Clinical Pearl:** Stage II low-risk (T1–T2, good differentiation, no LVI, adequate nodal sampling) may be observed without adjuvant therapy; high-risk stage II requires FOLFOX. [cite:ASCO Colorectal Cancer Adjuvant Therapy Guidelines; NCCN Colorectal Cancer v3.2023]