Nucl Med Mol Imaging.  2023 Oct;57(5):223-234. 10.1007/s13139-023-00808-3.

Contribution of Metabolic Parameters and Pericolic Fat Stranding on Preoperative 18F‑FDG PET/CT in Predicting Post‑operative Histopathology and Outcome in Colorectal Cancer

• Soyluoglu S
• Gunay B

• KMID: 2547011
• DOI: http://doi.org/10.1007/s13139-023-00808-3

Abstract

Purpose
We aimed to investigate the additional value of preoperative PET/CT and reveal relationships between metabolic parameters, pericolic fat stranding finding, postoperative histopathology, and overall survival in colorectal cancer (CRC).
Methods
CRC patients who underwent preoperative PET/CT between January 2017-December 2021 were analyzed. Lymph nodes, organ metastases, and metabolic parameters were evaluated from PET/CT. The pericolic fat stranding was evaluated from CT component. Relationships between these factors and postoperative histopathological findings were statistically analyzed. Survival analyses were performed.
Results
Ninety-one patients (59 males, 32 females) were included in the study. All tumors showed high FDG uptake (mean SUVmax 19.5 ± 9.9). SUVmax of the tumor differed significantly at T3 and T4 stages (p = 0.041). A significant correlation was found between MTV, TLG values and the differentiation degree (p = 0.005, 0.003, respectively). PET/CT predicted the N stage with a high accuracy rate (80%). PET/CT found additional metastases that changed treatment decisions in one-third of patients. A relationship was found between tumor length, surgical margin, lymphovascular invasion and pericolic fat stranding. In multivariate analysis, differentiation degree (HR = 26.1, 95%CI 1.672–408.467), MTV (HR = 0.3, 95%CI 0.071–0.841), TLG (HR = 3.5, 95%CI 1.065–11.193), and lymphovascular invasion (HR = 0.2, 95%CI 0.026–0.853, p = 0.033) were independent factors affecting overall survival.
Conclusion
Preoperative PET/CT contributes to CRC management by detecting additional metastases as well as predicting prognosis and postoperative findings such as T stage, N stage and tumor differentiation. The SUVmax may differentiate between T3 and T4 tumor. Reporting of pericolic fat stranding may contribute to the estimation of lymphatic invasion and positive surgical margin.

Keyword

F-18-FDG PET; PET/CT; FDG; Colorectal cancer; Colon cancer; Pericolic fat stranding