Synopsis
Explain how preoperative radiotherapy, chemoradiotherapy or total neoadjuvant strategies reduce local or distant relapse risk in selected rectal cancer and how total mesorectal excision preserves the mesorectal fascial envelope.
- Neoadjuvant treatment selection follows MRI-defined local risk, metastatic risk, tumour height and patient fitness.
- Short-course pelvic radiotherapy commonly delivers 25 Gy in five daily fractions; representative long-course chemoradiotherapy delivers 45 Gy in 25 daily fractions with concurrent fluoropyrimidine and a protocol-selected boost when indicated.
- Total neoadjuvant therapy adds systemic chemotherapy before surgery to neoadjuvant radiotherapy or chemoradiotherapy; select it for a defined stage, systemic-risk or response goal rather than applying it to every rectal tumour.
Key red flags
Vomiting with distension and obstipation needs urgent obstruction assessment. Fever or acute deterioration during concurrent chemotherapy may be neutropenic sepsis and must not wait for the next oncology review.
Reasoning priorities
Define local stage, radial-margin risk and distant disease before selecting treatment order.
Record cT, cN, mesorectal fascia, EMVI, sphincter and levator involvement; resectable non-metastatic locally advanced disease triggers the preoperative-treatment offer.
Worked reasoning
A fit 60-year-old has a low rectal adenocarcinoma staged cT3 cN1 M0 with EMVI and tumour 1 mm from the mesorectal fascia; sphincters and levators are clear.
- Confirm tissue diagnosis, complete-colon examination, high-resolution pelvic MRI, CT chest/abdomen/pelvis, baseline CEA, continence, renal function, blood count and performance status.
- At specialist rectal MDT, classify the threatened radial margin and node-positive cT3 M0 stage as requiring an offer of preoperative radiotherapy or chemoradiotherapy under NICE.
- Select long-course chemoradiotherapy because downstaging is important for radial clearance: 45 Gy in 25 daily fractions with concurrent fluoropyrimidine, plus any boost specified by the oncology protocol. Document renal, marrow and performance fitness, fertility discussion where relevant, and acute bowel, urinary and skin risks.
- Restaging shows a smaller residual lesion with a clear predicted plane, so proceed to laparoscopic low anterior resection with TME and a protective-stoma decision based on the anastomosis and patient risk.
- Pathology is ypT2 ypN0, 0 of 20 nodes, complete mesorectal plane and 7 mm circumferential margin. Verify the MDT’s adjuvant decision and monitor bowel, urinary, sexual and stoma outcomes.