Clinical Report: Utilizing Preoperative 18F-FDG PET/CT in Colorectal Cancer

Overview

This study evaluates the diagnostic performance of preoperative 18F-FDG PET/CT in detecting synchronous neoplasms in patients with acute left-sided obstructive colorectal cancer. The findings indicate that PET/CT has high specificity (95.0%) but moderate sensitivity (77.8%) for invasive synchronous colorectal cancer.

Background

Synchronous colorectal cancers (sCRC) can occur in 3%-6% of colorectal cancer patients, complicating surgical decision-making in obstructive colorectal cancer (OCC). The inability to perform complete preoperative colonoscopy in these patients increases the risk of missing additional malignancies.

Data Highlights

Key Findings

• Invasive sCRC was confirmed in 9 patients (6.0%) and CSN in 17 patients (11.4%).

• For invasive sCRC, PET/CT demonstrated a sensitivity of 77.8% and specificity of 95.0%.

• The negative predictive value (NPV) for invasive sCRC was 98.5%, indicating a low rate of missed cancers.

• Among 135 PET-negative patients, only 2 (1.5%) had invasive sCRC.

• Secondary curative resection was required in 5 patients (3.4%) and therapeutic endoscopy in 8 (5.4%).

Clinical Implications

Preoperative 18F-FDG PET/CT may assist in identifying patients who require further assessment for synchronous neoplasms.

Conclusion

The study evaluates the role of preoperative 18F-FDG PET/CT in surgical decision-making for patients with acute left-sided obstructive colorectal cancer.

Related Resources & Content

1. Bachmann, J., et al., 2017 -- The Role of 18F-FDG PET/CT in the Diagnosis of Synchronous Colorectal Cancer

2. European Radiology, 2024 -- Guidelines for Staging and Restaging in Oncology Using FDG-PET/CT

3. Frontiers in Oncology, 2026 -- Diagnostic performance of 18F-FDG PET-CT and SPECT for bone metastases from colorectal cancer

4. European Radiology, 2026 -- Improved detection of local tumor progression after ablation or resection of colorectal liver metastases

5. ACR Appropriateness Criteria® Colorectal Cancer Screening: 2024 Update

6. Localised colon cancer: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up

7. The American Society of Colon and Rectal Surgeons Clinical Practice Guidelines for the Management of Colon Cancer

8. Fluoro-2-deoxy-d-glucose positron emission tomography/computed tomography for the detection of proximal synchronous lesions in patients with obstructive colorectal cancer

9. PET/CT Integrated With CT Colonography in Preoperative Obstructive Colorectal Cancer by Incomplete Optical Colonoscopy

10. Diagnostic accuracy and treatment benefit of PET/CT in staging of colorectal cancer compared to conventional imaging

11. https://coloproctol.org/upload/pdf/ac-2024-00059-0008.pdf

12. ACR Appropriateness Criteria® Colorectal Cancer Screening: 2024 Update - PubMed

13. Localised colon cancer: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up - ScienceDirect

14. The American Society of Colon and Rectal Surgeons Clinical Practice Guidelines for the Management of Colon Cancer