Total Neoadjuvant Therapy for Locally Advanced Rectal Cancer

Introduction to Total Neoadjuvant Therapy

The American Society of Clinical Oncology recommends total neoadjuvant therapy (TNT) as initial treatment for patients with locally advanced rectal cancer, particularly those with lower rectal tumors and/or high-risk features, with a strength of evidence of high 1, 2, 3

Pathologic complete response rates are significantly higher with TNT (22.4%) compared to standard chemoradiation (14.3%), representing a clinically meaningful improvement in tumor regression, with moderate strength of evidence 3
TNT improves 5-year overall survival with a hazard ratio of 0.78 (95% CI 0.62-0.97), demonstrating a mortality benefit over standard treatment, with high strength of evidence 3

The National Comprehensive Cancer Network prefers the TNT sequence of long-course chemoradiotherapy (50.4 Gy with concurrent fluoropyrimidine) followed by consolidation chemotherapy (FOLFOX or CAPOX for 4-6 cycles), then surgery 6-8 weeks after completing chemotherapy, with high strength of evidence 1, 2, 3, 4

The European Society for Medical Oncology strongly recommends TNT for patients with T4 tumors, lower rectal tumors, EMVI-positive on MRI, tumor deposits, threatened mesorectal fascia, or threatened intersphincteric plane, with high strength of evidence 1, 2, 3

The American College of Surgeons notes that chemotherapy compliance rates are significantly higher with TNT compared to adjuvant therapy, as patients receive systemic treatment before the physiological stress of surgery, with moderate strength of evidence 3
TNT enables organ preservation strategies for patients achieving clinical complete response, particularly valuable for those requiring abdominoperineal resection with permanent colostomy, with high strength of evidence 3, 5

The National Cancer Institute recommends that all patients must undergo high-resolution pelvic MRI with dedicated rectal sequence, including standardized synoptic reporting, before initiating any treatment, with high strength of evidence 1, 2, 3
MSI/MMR status must be assessed prior to treatment commencement, as MSI-high/dMMR tumors should receive immunotherapy rather than TNT, with high strength of evidence 1, 2, 3

The American Society of Clinical Oncology notes that grade 3+ adverse events occur in approximately 38% of patients undergoing TNT, requiring careful patient selection and monitoring, with moderate strength of evidence 3
Triplet chemotherapy regimens like FOLFIRINOX carry higher toxicity (35.9% grade 3+ events) and may be inappropriate for patients with significant comorbidities or age >76 years, with high strength of evidence 1, 3

The European Society for Medical Oncology recommends that for patients with MSI-high or dMMR locally advanced rectal cancer, immunotherapy is the recommended treatment rather than TNT, as immunotherapy achieves exceptionally high complete response rates (up to 100% in some series) without the toxicity of chemoradiation, with high strength of evidence 3, 4, 5