MRI‑based neoadjuvant therapy indication in middle and low rectal cancer

Area of Science:

• Oncologic imaging and treatment strategies.
• Rectal cancer diagnosis and staging.

Background:

• Optimal treatment for rectal cancer remains debated despite diagnostic advances.
• Current guidelines recommend neoadjuvant therapy for UICC stage II+ rectal cancer.
• MRI-derived variables like mesorectal fascia distance and resection margin influence treatment decisions.

Purpose of the Study:

• To evaluate the indication for neoadjuvant therapy in middle and low rectal cancer.
• To assess the accuracy of MRI in staging rectal cancer.
• To compare MRI staging with histopathological findings.

Main Methods:

• Prospective data collection from 101 rectal cancer patients (2013-2018).
• Comparison of MRI staging accuracy against definitive histopathology.
• Exclusion of 9 patients diagnosed with benign lesions post-histopathology.

Main Results:

• No significant difference observed between MRI and histopathological T-staging in 92 patients.
• Significant discrepancies found in N-staging between preoperative MRI and postoperative histopathology.
• MRI T-staging accuracy was comparable to histopathology.

Conclusions:

• Preoperative lymph node staging using MRI is inefficient, potentially leading to overtreatment.
• Neoadjuvant therapy, while beneficial, has side effects and should be reserved for patients who will benefit.
• Improved staging accuracy is needed to optimize neoadjuvant therapy indications in rectal cancer.