Contribution of tubarial salivary gland function detected through 68 Ga-prostate-specific membrane antigen PET/computed tomography to total salivary gland function.

[OBJECTIVE] This study aimed to determine the contribution of tubarial salivary glands to total salivary gland function using quantitative parameters obtained from 68 Ga-prostate-specific membrane antigen (PSMA) PET/computed tomography (PET/CT), including salivary gland volume (SV) and salivary gland function (SF).

[METHOD] This retrospectively designed study included 102 patients with prostate cancer (PCa) who had undergone 68 Ga-PSMA PET/CT for staging purposes between January 2022 and December 2023. Patients with missing data, those with tumors in the head and neck region, those who received radiotherapy to the head and neck region, those who underwent surgery in the head and neck region, those with any salivary gland-related disease, those previously treated with radioactive iodine, and those who received lutetium-177 ( 177 Lu) therapy were excluded from the study.

[RESULTS] All 102 patients included in the study were male and diagnosed with PCa. The mean age of the patients was calculated as 72.53 ± 7.58 years. Patients' tubarial SV% and tubarial SF% values were calculated as 7.76 ± 4.01 and 2.58 ± 1.34, respectively. The percentage volume of tubarial glands was found to be statistically significantly higher than that of sublingual glands ( P < 0.001, Wilcoxon signed-rank test). No statistical difference, however, was observed in their contributions to total function ( P = 0.506).

[CONCLUSION] When examining the volume ratios of salivary glands showing PSMA expression, it was found that the tubarial salivary glands had a higher volumetric ratio but a lower contribution to total function. We recommend considering these ratios when administering treatments that affect salivary gland functions.