A 58-year-old man from rural Maharashtra presents with a 3-month history of altered bowel habits, abdominal pain, and weight loss. On examination, a palpable mass is felt in the left lower abdomen. Colonoscopy reveals a stenosing lesion in the sigmoid colon with biopsy confirming adenocarcinoma. CT abdomen shows the tumour invading the muscularis propria with no distant metastases, but 2 out of 12 regional lymph nodes are involved. What is the most appropriate next step in management?

Explanation

## Clinical Assessment This patient has **Stage III colorectal cancer (T2N1M0)** — the tumour invades the muscularis propria (T2), with 2 out of 12 regional lymph nodes involved (N1), and no distant metastases (M0). ## Staging Summary | TNM Stage | T | N | M | 5-yr Survival | |-----------|---|---|---|---------------| | Stage II | T3–T4 | N0 | M0 | 65–75% | | **Stage IIIA** | **T1–T2** | **N1** | **M0** | **~60–70%** | | Stage IIIB | T3–T4 | N1–N2 | M0 | 40–55% | | Stage IV | Any | Any | M1 | <10% | **Key Point:** The stem states the tumour invades the muscularis propria (T2) with N1 disease — this is Stage IIIA colon cancer. ## Standard Management of Resectable Stage III Colon (Sigmoid) Cancer **High-Yield:** The critical distinction in colorectal cancer management is between **colon cancer** and **rectal cancer**: - **Rectal cancer (Stage II–III):** Neoadjuvant chemoradiotherapy → Total Mesorectal Excision (TME) → adjuvant chemotherapy - **Colon cancer (including sigmoid, Stage III):** **Immediate surgical resection (hemicolectomy/sigmoidectomy) → adjuvant chemotherapy (FOLFOX or CAPOX)** For **sigmoid colon adenocarcinoma** that is **resectable** (no distant metastases, no unresectable local invasion), the standard of care per ASCO, NCCN, ESMO, and Indian textbooks (Bailey & Love, Sabiston) is: 1. **Upfront surgical resection** with adequate margins and lymph node clearance (≥12 nodes) 2. Followed by **adjuvant chemotherapy** (FOLFOX/CAPOX) for Stage III disease Neoadjuvant chemotherapy for colon cancer remains **investigational** (e.g., FOxTROT trial) and is **not yet standard practice** in Indian medical curricula or mainstream guidelines for resectable sigmoid colon cancer. ## Rationale for Correct Answer **Immediate surgical resection without neoadjuvant therapy** is the most appropriate next step because: 1. **Resectable disease:** CT shows no distant metastases and the tumour is technically resectable — surgery is not contraindicated. 2. **Standard of care:** For non-rectal colon cancer, upfront surgery followed by adjuvant chemotherapy is the established guideline-concordant approach (ASCO/NCCN/ESMO). 3. **Sigmoid ≠ Rectum:** Neoadjuvant chemoradiotherapy is reserved for rectal cancer (within 15 cm of anal verge); this lesion is in the sigmoid colon. 4. **Adjuvant chemotherapy** (FOLFOX) will be administered post-operatively given N1 status, providing systemic disease control. **Clinical Pearl:** Neoadjuvant therapy for colon cancer is only considered in borderline resectable or locally unresectable cases (e.g., T4b with adjacent organ invasion). For resectable Stage III sigmoid colon cancer, immediate surgery followed by adjuvant chemotherapy remains the standard per Bailey & Love's Surgery, Sabiston Textbook of Surgery, and NCCN Guidelines. ## Why Other Options Are Incorrect - **A (Palliative colostomy + chemotherapy):** Incorrect — this is curative-intent disease; palliative approach is inappropriate. - **B (Endoscopic stent + observation):** Incorrect — stenting is a bridge to surgery in acute obstruction, not definitive management. - **C (Neoadjuvant chemotherapy → surgery):** Incorrect for resectable sigmoid colon cancer; neoadjuvant chemotherapy is standard for rectal cancer, not sigmoid colon cancer in current practice. [cite: Bailey & Love's Short Practice of Surgery, 27e; NCCN Guidelines Colon Cancer v2.2024; Harrison's Principles of Internal Medicine 21e Ch 99]