Preoperative Radiotherapy in Rectal Adenocarcinoma

Benefits of Preoperative Radiotherapy

Preoperative radiotherapy significantly reduces local recurrence rates compared to surgery alone, with a reduction in local recurrence rates, as recommended by the European Society for Medical Oncology 1, 2, 3
Short-course radiotherapy (25 Gy, 5 Gy/fraction followed by immediate surgery) effectively reduces local recurrence, according to the European Society for Medical Oncology 5

Due to decreased toxicity, preoperative chemoradiotherapy is preferred over postoperative chemoradiotherapy, as stated by the European Society for Medical Oncology 1, 2, 3, 4

For early, favorable cases (cT1-2, some early cT3, N0), surgery alone using total mesorectal excision (TME) is appropriate, as recommended by the European Society for Medical Oncology 6
For intermediate cases (most cT3 without threatened mesorectal fascia, some cT4a, N+), preoperative radiotherapy followed by TME is recommended, according to the European Society for Medical Oncology 6, 5
For locally advanced, non-resectable cases (cT3 with threatened mesorectal fascia, cT4 with organ involvement), preoperative chemoradiotherapy followed by surgery 6-8 weeks later is recommended, as stated by the European Society for Medical Oncology 6, 5

Short-course radiotherapy: 25 Gy in 5 fractions over 1 week, followed by surgery within 10 days, as recommended by the European Society for Medical Oncology 6, 5
Long-course chemoradiotherapy: 45-50.4 Gy in 1.8-2 Gy fractions with concurrent 5-FU (bolus, continuous infusion, or oral), according to the European Society for Medical Oncology 6, 5

Preoperative staging must be accurate to select appropriate patients for preoperative treatment - endoscopic ultrasound or rectal MRI is recommended, as stated by the European Society for Medical Oncology 1, 2, 3, 4
The quality of the mesorectal excision significantly impacts outcomes and should be evaluated by the surgeon and/or pathologist, according to the European Society for Medical Oncology 6
Combinations of 5-FU with other cytostatics or targeted biological drugs have shown higher pathologic complete response rates but also increased toxicity, as reported by the European Society for Medical Oncology 5, 7