A 58-year-old man from Delhi presents with a 3-month history of altered bowel habits, tenesmus, and blood-stained stools. Digital rectal examination reveals a hard, irregular mass 6 cm from the anal verge. Colonoscopy confirms a stenosing lesion of the rectosigmoid with biopsy-proven adenocarcinoma. CT staging shows a T3N1M0 tumour with no distant metastases. The patient is fit for surgery with no significant comorbidities. What is the most appropriate next step in management?

Explanation

## Clinical Context This patient has locally advanced rectal cancer (T3N1M0) with nodal involvement. The tumour location (6 cm from anal verge) places it in the rectum, making sphincter preservation a key consideration. ## Rationale for Neoadjuvant Chemoradiotherapy **Key Point:** Neoadjuvant chemoradiotherapy (nCRT) is the standard of care for locally advanced rectal cancer (T3–T4 or N+) in the modern era. **High-Yield:** The benefits of nCRT in rectal cancer include: 1. Downstaging of the tumour, improving resectability and sphincter preservation rates 2. Reduction of local recurrence risk from ~25% to ~5–8% 3. Improved overall survival compared to adjuvant therapy alone 4. Better tolerance (fewer acute toxicities than adjuvant CRT) **Clinical Pearl:** The interval between completion of nCRT and surgery is typically 6–8 weeks to allow maximal tumour regression and tissue healing. ## Treatment Algorithm ```mermaid flowchart TD A[Rectal cancer diagnosed]:::outcome --> B{Stage?}:::decision B -->|T1-T2, N0| C[Direct surgery]:::action B -->|T3-T4 or N+| D[Neoadjuvant CRT]:::action D --> E[6-8 week interval]:::action E --> F[Total mesorectal excision]:::action C --> G[Adjuvant chemo if high-risk]:::action F --> H[Adjuvant chemo if residual disease]:::action ``` ## Why This Patient Qualifies - **T3 disease:** Tumour invades through muscularis propria into perirectal fat — requires nCRT - **N1 nodal involvement:** Regional node metastases mandate neoadjuvant approach - **Fit for surgery:** No contraindications; can tolerate combined modality therapy - **Sphincter preservation feasible:** Tumour is 6 cm from anal verge (>5 cm margin achievable with anterior resection post-downstaging) ## Post-nCRT Management After completion of nCRT and restaging (typically by MRI), the patient proceeds to **total mesorectal excision (TME)** with anterior resection and primary anastomosis if sphincter function is adequate. [cite:Harrison 21e Ch 297]