Can Initial 18F-FDG PET-CT Imaging Give Information on Metastasis in Patients with Primary Renal Cell Carcinoma?

Abstract

PurposeThe aim of this study was to investigate the relationship between the maximum standardized uptake values (SUVmax) of primary renal cancers with and without metastatic lesions, if any. We also studied the relationship between the size of primary renal cancers and their SUVmax, and tried to find a clinical value of 18F-FDG PET-CT for the initial evaluation of renal cell carcinoma (RCC).MethodsThe cases of 23 patients, 16 men and 7 women, who underwent PET-CT examination before operation were retrospectively reviewed. We measured the SUVmax of the primary renal cancers and those of any existing metastatic lesions, and the size of the primary renal cancers. We compared the SUVmax of primary RCCs with metastases and those without metastases, SUVmax of primary RCC and those of metastases, and studied the correlation between the size and SUVmax of primary RCCs.ResultsThe SUVmax of primary RCC of the 16 patients without metastasis ranged from 1.1 to 5.6 with a median value of 2.6. Those of the patients with metastasis ranged from 2.9 to 7.6 with a median of 5.0. The size of the all 23 primary renal cancers ranged from 1.7 cm to 13.5 cm, with a median of 4.5 cm, and their SUVmax ranged from 1.1 to 7.6, with a median of 2.9. There was a statistically significant difference between the SUVmax of the primary RCC with metastasis (5.3 ± 1.7) and those without metastasis (2.9 ± 1.0). There was a moderate positive correlation between the sizes and SUVmax of all 23 primary RCCs. However, there was no statistically significant correlation between the sizes and SUVmax of primary RCCs with metastatic lesions and the same for RCCs without metastasis. The cutoff value of SUVmax for predicting extra-renal lesion was 4.4 and that for size was 5.8 cm according to the receiver operating characteristic curves.ConclusionsThose who have primary RCC with high SUVmax are suggested to have a likelihood of metastasis. Also, there was a moderate trend of increasing value of SUVmax of primary RCC as their size increases. Physicians should beware of missing extra-renal lesions elsewhere.

The Place of FDG PET/CT in Renal Cell Carcinoma: Value and Limitations

“…The highest FDG accumulation was seen in the tumor of the highest grade, and the highest mortality was found for tumors exceeding SUV max of 10. Lee et al investigated the relationship between the SUV max of primary RCC with and without metastatic lesions in 23 patients ( 20 ). The median SUV max of primary RCC of the 16 patients without metastasis was 2.6 (range of 1.1–5.6) while that of the patients with metastasis was 5.0 (range of 2.9–7.6).…”

Role of positron emission tomography/computed tomography in the evaluation of renal cell carcinoma

“…found that the median SUVmax of the primary RCC of 16 patients without metastasis was 2.6 (range of 1.1–5.6) while that of the patients with metastasis was 5.0 (range of 2.9–7.6). [ 30 ] Thus FDG PET/CT may help in predicting the extrarenal disease, as a primary RCC with a high SUVmax has a higher likelihood of having occult metastasis. Besides the SUV values, metabolic parameters such as the metabolic tumor volume and the total lesion glycolysis calculated with PET imaging also have a prognostic significance as suggested by Hwang et al .…”

Imaging of renal cell carcinoma

“…Finally, a retrospective study looked at FDG PET in 23 patients, which was acquired before nephrectomy. The study concluded that a high standardized uptake value max at primary RCC reflected a higher likelihood of metastatic disease (5.3 Ϯ 1.7 in metastatic disease vs. 2.9 Ϯ 1.0 in nonmetastatic disease) [65].…”