The impact of [Ga]PSMA I&T PET/CT on radiotherapy planning in patients with prostate cancer

PURPOSE: To determine the impact of Gallium-68-labled prostate-specific membrane antigen positron-emission tomography/computed tomography ([68Ga]PSMA PET/CT) on radiotherapy planning for primary disease, biochemical cancer relapse, and advanced disease of prostate cancer.

METHODS: A total of 106 patients with prostate cancer scheduled for radiation therapy underwent 120 [68Ga]PSMA PET/CT scans prior to radiotherapy treatment. In 20 cases, patients underwent [68Ga]PSMA PET/CT for primary therapy (PT), 75 cases were referred for biochemical relapse after surgery (RL), and 25 cases were intended for palliative treatment of localized metastases (MD). We retrospectively compared the impact of [68Ga]PSMA PET/CT on lesion detection and treatment decision to CT alone.

RESULTS: [68Ga]PSMA PET/CT revealed a total of 271 positive lesions, whereas CT detected 86 lesions (32%). Overall, the radiotherapy regime was changed in 55 of 120 cases (46%) based on the higher detection rate of [68Ga]PSMA PET/CT: in 15% of cases with PT, in 43% of cases with RL, and in 44% of cases with MD.

CONCLUSION: [68Ga]PSMA PET/CT is superior to CT alone for lesion detection in prostate cancer, thereby significantly impacting on radiotherapy planning for primary disease, biochemical cancer relapse, and advanced disease of prostate cancer.