Glucose metabolism of visceral adipose tissue measured by 18F-FDG PET/CT is related to the presence of colonic adenoma

Prognostic Significance of Adipose Tissue Distribution and Metabolic Activity in PET/CT in Patients with Metastatic Colorectal Cancer

PURPOSE

In this study, we aimed to evaluate the prognostic significance of adipose tissue distribution and metabolic activity in PET/CT to predict survival in patients with metastatic colorectal cancer (mCRC).

METHODS

The volume, density (HU), and FDG uptake (standardized uptake value (SUV)) of visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) and maximum FDG uptake of the tumor tissue were measured. Subcutaneous adipose tissue of volume-to-density ratio (SAT ratio) was calculated.

RESULTS

The median OS for the patients with SAT ratio value <  -1.1 and ≥  -1.1 were 38.5 (95% CI 31.54-45.58) and 24.5 (95% CI 14.13-34.93) months, respectively (p = 0.05). During follow-up, 69 patients experienced disease progression. The median progression-free survival (PFS) was 11.03 months (95% CI: 9.11-12.95). Median PFS for patients with tumor SUV max value < 11.5 and ≥ 11.5 were 9.2 (95% CI 7.25-11.27) and 12.6 (95% CI 10.02-15.27) months, respectively (p = 0.14). Forty-eight patients received bevacizumab therapy. VAT SUV mean (HR: 0.09; 95% CI 0.01-0.52, p = 0.008) was significantly associated with PFS in patients receiving bevacizumab. SAT ratio was the significant parameter for the OS (HR: 0.58; 95% CI 0.33-1.01, p = 0.05) and PFS (HR: 1.99; 95% CI 1.02-3.91, p = 0.043).

CONCLUSIONS

SAT ratio was an independent prognostic factor for survival in patients with mCRC. Higher SAT volume is correlated with longer survival in mCRC patients.

Blood pool activity on F-18 FDG PET/CT as a possible imaging biomarker of metabolic syndrome

Association of blood pool (BP) and adipose tissue activity from F-18 fluorodeoxyglucose positron-emission tomography/computed tomography (FDG PET/CT) with the parameters of metabolic syndrome (MetS) and different MetS/obesity types were investigated. 245 subjects underwent FDG PET/CT scan for health check-ups were investigated retrospectively. Associations of BP (BP SUV: SUV_max, SUV_mean), visceral (VAT SUV), and subcutaneous adipose tissue (SAT SUV) activity with parameters of MetS, body mass index (BMI), and lipid profiles were analyzed. MetS/obesity types were subdivided into metabolically healthy obese (MHO) and metabolically unhealthy obese (MUO). BP SUV was higher in subjects with MetS (t-test, P < 0.005), and was associated with MetS from multivariable binary logistic regression (OR 5.232 P = 0.010). BP SUV was statistically higher in MUO than in MHO (P < 0.05) along with blood pressure, triglycerides, and HDL-cholesterol. Multivariable binary logistic regression analysis showed MUO had higher blood pressure and BP SUV, while lower HDL-cholesterol relative to MHO after adjusting for triglycerides.

[Role of adipose tissue in the development and progression of colorectal cancer]

The paper gives the current data available in the literature on the relationship and pathogenetic mechanisms of influence of adipose tissue on colorectal carcinogenesis. It considers the aspects of changes in adipose tissue and microenvironment of the tumor itself, including those under the influence of biologically active substances secreted by adipocytes; differences in subcutaneous and visceral fat and their importance in the development and progression of colorectal cancer (CRC), as well as the role of adipose tissue-derived stem cells. Understanding these mechanisms for adipose tissue influence on CRC will assist not only in preventing this disease, but also in searching for new therapeutic targets.

Usefulness of metabolic activity of adipose tissue in FDG PET/CT of colorectal cancer

PURPOSE

To determine the relationship between metabolic activity of adipose tissue on FDG PET/CT and prognosis in colorectal cancer.

METHODS

A total of 176 colorectal cancer patients with curative surgical resection were retrospectively enrolled. Volume and metabolic activity of subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) on FDG PET/CT images were measured. The maximum standardized uptake value (SUV) of primary tumor (SUVtumor) was also obtained. Univariate analysis with log-rank test and multivariate Cox regression analyses were used to evaluate prognostic values of volume and metabolic activity of SAT and VAT as well as SUVtumor and clinicopathologic factors.

RESULTS

Of 176 patients, 26 experienced recurrence during follow-up. SUVtumor showed significant correlation with serum C-reactive protein level (r = 0.242, p = 0.001), SUV of VAT (r = 0.167, p = 0.026), and size of primary tumor (r = 0.341, p < 0.001). In univariate analysis with log-rank test, SUV of VAT (p = 0.009) and SAT (p = 0.006), volume of VAT (p = 0.015), N stage (p < 0.001), M stage (p < 0.001), tumor involvement of resection margin (p = 0.001), and lymphatic invasion (p = 0.024) were significantly associated with recurrence-free survival (RFS). However, SUVtumor showed no significant association with RFS. In multivariate Cox regression analysis, SUV of VAT (p = 0.016), presence of lymph node metastasis (p < 0.001), and tumor involvement of resection margin (p = 0.011) were independent prognostic factors for RFS.

CONCLUSIONS

The SUV of VAT in patients with colorectal cancer is significantly associated with FDG uptake of primary tumor. It is an independent predictor for RFS.