Preoperative ¹⁸F-FDG PET/CT in Patients with Presumed Localized Colon Cancer: A Prospective Study with Long-Term...

Area of Science:

• Oncology
• Nuclear Medicine
• Radiology

Background:

• Accurate staging of colonic cancer (CC) is crucial for treatment planning.
• Conventional imaging may miss certain primary lesions or metastases.
• The role of 18F-FDG PET/CT in primary CC staging requires further elucidation.

Purpose of the Study:

• To evaluate the added diagnostic value of preoperative 18F-FDG PET/CT to conventional staging in patients with presumed non-metastatic colonic cancer.
• To assess the prognostic role of primary tumor 18F-FDG uptake after long-term follow-up.

Main Methods:

• Prospective enrollment of 48 patients with presumed localized CC undergoing presurgical 18F-FDG PET/CT.
• Assessment of SUVmax, SUVpeak, TLG, and MTV for colon lesions.
• Comparison of 18F-FDG PET/CT with conventional workup for primary tumor and nodal staging.
• Analysis of prognostic factors and long-term outcomes (mean follow-up: 15 years).

Main Results:

• 18F-FDG PET/CT demonstrated higher sensitivity (94% vs. 78%) for primary tumor detection compared to conventional workup, identifying 10 additional lesions in 7 patients.
• Quantitative PET parameters (SUVmax, SUVpeak, TLG) differentiated between invasive adenocarcinomas and pre-malignant lesions, and between pT1-pT2 and pT3-pT4 stages.
• PET/CT identified unknown metastatic spread and one synchronous lung cancer in 4 patients (23% additional diagnostic value).
• Nodal staging sensitivity was slightly improved with PET/CT (33% vs. 22%), but without statistical significance.
• Primary tumor 18F-FDG uptake did not correlate with nodal/distant metastases or predict disease-free survival.

Conclusions:

• Preoperative 18F-FDG PET/CT enhances the detection of colonic lesions missed by conventional methods, especially in incomplete colonoscopies.
• PET/CT is effective in identifying distant metastases but has limitations in N staging.
• Quantitative 18F-FDG uptake in the primary tumor did not provide significant prognostic information regarding recurrence or survival in this cohort.