Updates of prostate cancer staging: Prostate-specific membrane antigen

68Ga-PSMA Uptake in Combined Hepatocellular Cholangiocarcinoma With Skeletal Metastases

Ga-PSMA PET is a rapidly evolving imaging modality for whole-body staging of prostate cancer. We report a case of a 70-year-old man with mildly elevated prostate-specific antigen (8.1 μg/L) and clinical suspicion of prostate cancer (osteoblastic metastases on radionuclide bone scan) who was referred for Ga-PSMA PET/CT for primary staging. Multiple Ga-PSMA-avid skeletal foci, mostly associated with lytic changes on low-dose CT, as well as hepatic foci of avid Ga-PSMA uptake, were identified. No abnormal focus of avid Ga-PSMA uptake was identified in the prostate. On histopathological examination, the liver lesion proved to be combined hepatocellular cholangiocarcinoma.

99m Tc-MIP-1404-SPECT/CT for the detection of PSMA-positive lesions in 225 patients with biochemical recurrence of prostate cancer

BACKGROUND

^99m Tc-MIP-1404 (Progenics Pharmaceuticals, Inc., New York, NY) is a novel, SPECT-compatible ^99m Tc-labeled PSMA inhibitor for the detection of prostate cancer. We present results of its clinical use in a cohort of 225 men with histologically confirmed prostate cancer referred for workup of biochemical relapse.

METHODS

From April 2013 to April 2017, ^99m Tc-MIP1404-scintigraphy was performed in 225 patients for workup of PSA biochemical relapse of prostate cancer. Whole-body planar and SPECT/CT images of the lower abdomen and thorax were obtained 3-4 h p.i. of 710 ± 64 MBq ^99m Tc-MIP-1404. Images were visually analyzed for presence and location of abnormal uptake. In addition, quantitative analysis of the SPECT/CT data was carried out on a subset of 125 patients. Follow-up reports of subsequent therapeutic interventions were available for 59% (139) of all patients.

RESULTS

Tracer-positive lesions were detected in 77% (174/225) of all patients. Detections occurred at the area of local recurrence in the prostate in 25% of patients (or a total of 56), with metastases in lymph nodes in 47% (105), bone in 27% (60), lung in 5% (12), and other locations in 2% (4) of patients. Detection rates were 90% at PSA levels ≥2 ng/mL and 54% below that threshold. Lesional SUVmax values were, on average, 32.2 ± 29.6 (0.8-142.2), and tumor-to-normal ratios 146.6 ± 160.5 (1.9-1482.4). The PSA level correlated significantly with total uptake of MIP-1404 in tumors (P < 0.001). Furthermore, total tumor uptake was significantly higher in patients with Gleason scores ≥8 compared to those with Gleason scores ≤7 (P < 0.05). In patients with androgen deprivation therapy, the detection rate was significantly higher compared to patients without androgen deprivation therapy (86% vs 71%, P < 0.001). Based on ^99m Tc-MIP-1404-imaging and other information, an interdisciplinary tumor board review recommended changes to treatment plans in 74% (104/139) of those patients for whom the necessary documentation was available.

CONCLUSION

SPECT/CT with ^99m Tc-labeled MIP-1404 has a high probability in detecting PSMA-positive lesions in patients with elevated PSA. Statistical analysis disclosed significant relationship between quantitative ^99m Tc-MIP-1404 uptake, PSA level, and Gleason score.

The Role of Local Therapy for Oligometastatic Prostate Cancer: Should We Expect a Cure?

The role of local treatment in oligometastatic prostate cancer remains contentious. Treatment of the prostate in metastatic disease may confer benefit, but prospective data are lacking. With improvements in treatments, aggressive strategies directed at metastases have increasingly become of clinical interest. Current evidence suggests good local control can be achieved; however, further data are required to determine overall cancer outcomes. This article evaluates the evidence available and consider whether local treatment of oligometastatic disease is a feasible, safe, and a positive strategy in this disease cohort. Cure should not be expected, although prolonged disease and treatment-free survival may be observed.

The Impact of 68Ga-PSMA PET/CT on Management Intent in Prostate Cancer: Results of an Australian Prospective Multicenter Study

⁶⁸Ga-PSMA PET/CT scanning has been shown to be more sensitive than conventional imaging techniques in patients with prostate cancer. This prospective Australian multicenter study assessed whether ⁶⁸Ga-PSMA PET/CT imaging affects management intent in patients with primary or recurrent prostate cancer. Methods: Before undertaking ⁶⁸Ga-PSMA PET imaging, referring medical specialists completed a questionnaire detailing relevant demographic and clinical data as well as their proposed management plan. A separate follow-up questionnaire was completed after the ⁶⁸Ga-PSMA PET/CT scan results were available to determine whether the management plan would change. Results: A total of 431 patients with prostate cancer from 4 Australian centers had pre- and post-⁶⁸Ga-PSMA management plans completed. Scans were obtained for primary staging of intermediate- and high-risk disease in 25% of patients and for restaging/biochemical recurrence in 75% of patients. Overall, ⁶⁸Ga-PSMA PET/CT scanning led to a change in planned management in 51% of patients. The impact was greater in the group of patients with biochemical failure after definitive surgery or radiation treatment (62% change in management intent) than in patients undergoing primary staging (21% change). Imaging with ⁶⁸Ga-PSMA PET/CT revealed unsuspected disease in the prostate bed in 27% of patients, locoregional lymph nodes in 39%, and distant metastatic disease in 16%. Conclusion:⁶⁸Ga-PSMA PET/CT scans detect previously unsuspected disease and may influence planned clinical management in a high proportion of patients with prostate cancer. The impact was greater in patients with biochemical recurrence. These results demonstrate the potential clinical value of ⁶⁸Ga-PSMA PET/CT in management of prostate cancer.