Local recurrence in rectal cancer: from detection to structured reporting
Mohamed A Hamza1, Valesca Bizinoto2, Renata Vidal Leão3
1Department of Radiology, Mayo Clinic, Rochester, USA.
Abdominal Radiology (New York)
|August 7, 2026
Summary
Locally recurrent rectal cancer requires early detection for optimal treatment. Advanced imaging like MRI is crucial for distinguishing tumor from fibrosis and guiding surgical decisions.
Area of Science:
- Oncology
- Radiology
- Surgical Oncology
Background:
- Locally recurrent rectal cancer (LRRC) affects 2-10% of patients post-treatment, posing significant morbidity and mortality risks.
- Recurrences often occur within three years, near the surgical site, complicating early detection due to fibrosis and altered anatomy.
- Prompt diagnosis and complete resection (R0) are vital for durable disease control and survival.
Purpose of the Study:
- To review optimal multimodality imaging techniques for diagnosing and managing locally recurrent rectal cancer.
- To highlight the role of imaging in differentiating recurrent tumor from post-treatment changes and assessing resectability.
- To discuss emerging imaging applications for personalized patient management.
Main Methods:
- Contrast-enhanced CT for initial surveillance and detection of metastases or pelvic disease.
- High-resolution pelvic MRI with specific protocols (T2-weighted, diffusion-weighted, contrast-enhanced) for local characterization.
- Musculoskeletal MRI for posterior compartment recurrences involving the sacrum and nerve roots.
- FDG-PET/CT for equivocal findings and excluding distant metastases.
- Review of current literature on imaging modalities and their application in LRRC.
Main Results:
- CT is useful for surveillance but limited in distinguishing tumor from fibrosis in the pelvis.
- MRI is the preferred modality for local staging, assessing tumor extent, and involvement of adjacent structures.
- Dedicated sacral MRI aids in evaluating bone and nerve involvement, crucial for surgical planning.
- FDG-PET/CT is valuable for equivocal CT/MRI findings, though sensitivity varies.
- Hybrid FDG-PET/MRI shows promise but requires further validation for surgical management impact.
Conclusions:
- Accurate imaging is critical for timely diagnosis and effective management of locally recurrent rectal cancer.
- MRI, particularly with specialized protocols, is superior to CT for pelvic recurrence characterization.
- Multimodality imaging, including PET/CT and emerging techniques, aids in comprehensive staging and surgical planning.
- Structured reporting and future applications of AI and radiomics hold potential for individualized treatment strategies.
