The role of 68GA-PSMA PET-CT volumetric parameters in predicting treatment response in prostate cancer patients

Aim: We aimed to determine whether TL-PSMA, PSMA-TV, and SUVpeak values measured in prostate adenocarcinoma patients who underwent imaging with Ga-68 PSMA PET/CT for primary staging have a role in predicting treatment response. Method: Images of 68 patients who had Ga-68 PSMA PET/CT for primary staging between 25 March 2019 and 3 December 2021 were analyzed retrospectively. Volumetric parameter data were obtained by manual drawing with %40 threshold value for prostate gland, lymph nodes, bone, and visceral organ metastases. Results: TL-PSMA(Bone) measurement was statistically significantly different between the treatment-responsive and unresponsive groups (p=0.049). In addition, TL-PSMA and PSMA-TV parameters showed statistically significant differences between the treatment-responsive and unresponsive groups (p=0.02 and p=0.016). We could not find a significant relationship between other volumetric parameters and treatment response. Conclusion: It has been determined that the volumetric parameters obtained by Ga-68 PSMA PET/CT imaging performed for primary staging may have a role in predicting the treatment response in patients with prostate adenocarcinoma. However, new studies with larger patient groups are needed to clarify the issue. Keywords: PET/CT, Ga-68 PSMA, TL-PSMA, PSMA-TV