Prostate-specific Membrane Antigen PET: Therapy Response Assessment in Metastatic Prostate Cancer

Therapy response assessment is a critical step in cancer management, leading clinicians to optimize the use of therapeutic options during the course of the disease. Imaging is a pivotal biomarker for therapy response evaluation in oncology and has gained wider use through the development of reproducible data-based guidelines, of which the Response Evaluation Criteria in Solid Tumors is the most successful example. Disease-specific criteria have also been proposed, and the Prostate Cancer Working Group 3 criteria are the mainstay for prostate cancer (PC). However, conventional imaging evaluation in metastatic PC has several limitations, including (a) the inability to detect small-volume disease, (b) the high prevalence of bone (nonmeasurable) lesions at imaging, and (c) the established role of serum prostate-specific antigen (PSA) levels as the biomarker of choice for response assessment and disease progression. In addition, there are an increasing number of newer treatment options with various effects on imaging features. Prostate-specific membrane antigen (PSMA) PET has improved patient selection for newer treatments, such as metastasis-directed therapy (MDT) or radionuclide therapy. The role of PSMA PET in response assessment for many metastatic PC therapeutic options (MDT, androgen deprivation therapy, chemotherapy, radionuclide therapy, and immunotherapy) is an evolving issue, with emerging data showing good correlation with PSA levels and clinical outcome. However, there are specific implications of each therapy (especially androgen deprivation therapy and immunotherapy) on PSMA expression by PC cells, leading to potential pitfalls and inaccuracies that must be known by radiologists. Despite some limitations, PSMA PET is addressing gaps left by conventional imaging methods (eg, CT and bone scanning) and nonimaging biomarkers (PSA levels) in metastatic PC therapy response assessment, a role that can be improved with advances like refinement of interpretation criteria and whole-body tumor burden quantification.^© RSNA, 2020See discussion on this article by Barwick and Castellucci.

[Initial results on the use of mechanical devices for proximal saphenous vein graft anastomoses: a clinical and angiographic evaluation]

OBJECTIVE

To report on our initial clinical experience of the utilization of a mechanical anastomotic device (MAD) to perform saphenous vein graft to aorta anastomosis.

METHOD

Between June 2002 and May 2003, 17 patients, including 13 male, with a mean age of 64.4 +/- 9.4 years, were selected for coronary artery bypass grafting using MAD. A total of 49 anastomoses, 19 arterial and 30 vein grafts, were performed with a mean of 2.9 +/-0.5 anastomoses per patient. Eleven (36.7%) vein-graft anastomoses were performed with conventional sutures and 19 (63.3%) using MAD. The clinical evolution, enzymatic and electrocardiographic alterations as well as an angiographic study were analyzed in the postoperative period.

RESULTS

Of the 17 patients, the mechanical device was used on 16 (94.1%). Six (37.5%) patients were operated on under cardiopulmonary bypass with a mean time of 102.9 +/-16.9 minutes. The postoperative evolution was satisfactory in all patients. No patient presented with enzymatic, myocardial infarction or other ischemic electrocardiographic alterations in the immediate postoperative period. Early postoperative angiography was performed in 9 (52.9%) patients. The anastomoses of the left internal thoracic artery to left anterior descending artery were patent in all cases. Of the 15 saphenous vein grafts studied, 11 (73.3%) were performed using MAD, 9 (81.8%) of which were patent. All the 4 conventionally sutured vein anastomoses were patent. No hospital deaths occurred. In the late follow-up, 88.2% of the patients were free of cardiac-related events.

CONCLUSIONS

MAD for vein graft-to-aorta anastomoses proved to be feasible, but a wider analysis of the benefits of its utilization regarding operative time, aggression to the patient, patency of the grafts and final cost are necessary.