Lymph Nodes Evaluation in Rectal Cancer: Where Do We Stand and Future Perspective

Area of Science:

• Oncology
• Radiology
• Medical Imaging

Background:

• Nodal involvement assessment is critical for rectal cancer (RC) management.
• Current morphological criteria in MRI for nodal staging have limitations in sensitivity and specificity.
• Existing imaging modalities necessitate further validation for accurate lymph node evaluation in RC.

Purpose of the Study:

• To review current and emerging imaging techniques for assessing lymph node (LN) involvement in RC.
• To discuss the advantages and limitations of various advanced imaging modalities.
• To compare international guidelines for LN evaluation in RC.

Main Methods:

• Narrative review of established and experimental imaging techniques.
• Inclusion of advanced MRI sequences (DWI, IVIM, DKI, DCE) and PET/CT, PET/MRI.
• Discussion of experimental methods like SPIO and DECT, and radiomics analysis.

Main Results:

• Standard MRI criteria for nodal assessment in RC show limitations.
• Advanced MRI techniques and PET-based imaging show promise but need validation.
• Radiomics and novel techniques are emerging areas for LN assessment in RC.

Conclusions:

• Accurate lymph node staging in rectal cancer remains a challenge.
• Advanced imaging techniques show potential to improve diagnostic accuracy over conventional methods.
• Further research and validation are needed for widespread clinical adoption of novel techniques and adherence to guidelines.