Clinical impact of 68 Ga-prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) in patients with prostate cancer with rising prostate-specific antigen after treatment with curative intent: preliminary analysis of a multidisciplinary approach

To assess the impact of a novel molecular imaging technique, Ga-(HBED-CC)-prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT), in the clinical management of patients with prostate cancer with rising prostate-specific antigen (PSA) after treatment with curative intent. In all, 131 consecutive patients were referred to our centre for a Ga-PSMA PET/CT in the setting of recurring prostate cancer. Of these patients, 11/131(8%) presented with persistent PSA after radical prostatectomy, while 120/131 (92%) were referred for biochemical recurrence after surgery, radiotherapy or both. The images where taken 1 h after injection of 2 MBq/kg of the Ga-(HBED-CC)-PSMA ligand. All examinations were interpreted by two experienced nuclear medicine specialists. Using the results of the examination, a multidisciplinary oncology committee (MOC) reported on the treatment strategy. A positive impact on clinical management was considered if the examination determined a modification in the treatment strategy compared to the MOC decision before PSMA imaging. All patients completed the examination with no adverse reactions. The median (interquartile range) PSA level at the time of the examination was 2.2 (0.72-6.7) ng/mL. Overall, Ga-PSMA PET/CT detected at least one lesion suspicious for prostate cancer in 98/131 (75%) patients. There was an impact on subsequent management in 99/131 patients (76%). The main modifications included continuing surveillance (withholding hormonal therapy), hormonal manipulations, stereotaxic radiotherapy, salvage radiotherapy, salvage node dissection or salvage local treatment (prostatectomy, high-intensity focussed ultrasound). Our preliminary experience suggests that performing Ga-PSMA PET/CT in patients with prostate cancer with rising PSA after treatment with curative intent can be clinically useful as it changes the treatment strategy in a significant proportion of patients. However, larger prospective trials are needed to validate our present findings.