We often observed that ¹⁸F-FDG accumulation in gingival cancer with bone resorption was higher than that in tongue cancer. In this study, we statistically compared accumulation of ¹⁸ F-FDG in gingival cancer with bone resorption with accumulation in tongue cancer. We also compared it with ¹⁸F-labeled choline (¹⁸F-choline) PET to clarify the characteristics of ¹⁸F-FDG accumulation in bone resorption.

The subjects were 57 patients with gingival cancer and 34 patients with tongue cancer. Histologically, all cases were squamous cell carcinoma. ¹⁸F-FDG and ¹⁸F-choline accumulations were evaluated using the maximum standardized uptake value (SUV).

Comparison of ¹⁸F-FDG SUV between tongue cancer and gingival cancer without bone resorption showed no significant difference; however, the comparison between tongue cancer and gingival cancer with bone resorption resulted in values of 6.6 and 10.4, respectively, showing a significantly higher ¹⁸F-FDG SUV in gingival cancer accompanied by bone resorption (p = 0.001). The SUV of ¹⁸F-choline in tongue cancer was similar to that of ¹⁸F-FDG, but unlike with ¹⁸F-FDG, the SUV was not significantly higher in gingival cancer with bone resorption.

The mean ¹⁸F-FDG PET SUV was higher in gingival cancer with bone resorption than in tongue cancer, although this finding was not observed with ¹⁸F-choline. It was assumed that the high ¹⁸F-FDG SUV was due to accumulation in osteoblasts and osteoclasts involved in bone metabolism in addition to cancer stromal cells.