Society of Nuclear Medicine and Molecular Imaging | Jun 26, 2018
“Research presented at the 2018 Annual Meeting of the Society of Nuclear Medicine and Molecular Imaging (SNMMI) demonstrates for the first time the benefit of providing earlier lutetium-177 (177Lu) prostate-specific membrane antigen (PSMA) radioligand therapy to patients with metastatic prostate cancer. Until now, this therapy has only been used in patients with end-stage disease.”
“For prostate cancer patients who have rising levels of PSA (a cancer indicator) even after radical prostatectomy, early treatment makes a difference. In a study featured in the December issue of The Journal of Nuclear Medicine, Australian researchers demonstrate that PET scans can identify which of these prostate cancer patients would benefit from salvage radiation treatment (SRT).
” ‘The research is novel because it looks at the impact of PSMA PET/CT on patient responses to treatment, not just on whether the PET scan results in changed management,’ explains Louise Emmett, MD, of the St. Vincent’s Hospital, Sydney, Australia. She elaborates, ‘In the study, these patients underwent imaging with a PSMA PET scan and had treatment based on the results of the scan findings. The study then followed how these men were treated, and whether the treatment was effective.’ ”
“Therapy options are limited for men with advanced-stage, metastatic castration-resistant prostate cancer (mCRPC), but a new treatment protocol offers hope. In the featured article of The Journal of Nuclear Medicine‘s October issue, German researchers report on their recent clinical experience, which establishes a dosing regimen for actinium-225 (225Ac)-labeled targeted alpha therapy of patients with prostate specific membrane antigen (PSMA)-positive tumors. The protocol balances treatment response with toxicity concerns to provide the most effective therapy with the least side effects.”
“Imaging agents for the detection of biochemical recurrent prostate cancer could move beyond computed tomography (CT) and magnetic resonance imaging (MRI) in the near future, with the emergence of prostate-specific membrane antigen (PSMA)-PET, particularly in oligometastatic disease, with a high-detection sensitivity rate, explains Thomas Hope, MD.
“PSMA-PET uses small molecules that bind to PSMA, localizes a prostate cancer tumor, and allows radiologists to image patients after 1 hour to detect small sites of disease. Hope and researchers at the University of California, San Francisco (UCSF) are dedicated to bringing this imaging modality to the FDA for approval with diagnostic data as evidence.”
“Researchers presenting a preclinical study at the 2017 Annual Meeting of the Society of Nuclear Medicine and Molecular Imaging (SNMMI) demonstrated the efficacy and optimal dose for targeted photodynamic therapy (tPDT) to treat prostate cancer before and during surgery. Prostate-specific membrane antigen (PSMA) was targeted with an anti-PSMA antibody radiolabeled with the tracer indium-111 (111In) and coupled with specialized photosensitizers that cause cell destruction upon exposure to near-infrared (NIR). The combined formula is 111In-DTPA-D2B-IRDye700DX.
” ‘Coupling the photosensitizer to an imaging agent that targets PSMA on the tumor surface makes it possible to selectively and effectively destroy prostate tumor remnants and micrometastases while surrounding healthy tissues remain unaffected,’ said Susanne Lütje, MD, PhD, lead author of the study from the Department of Radiology and Nuclear Medicine at Radboud University Medical Center in Nijmegen, the Netherlands, and the Clinic for Nuclear Medicine at University Hospital Essen, Germany.”
“The researchers are using the small molecule Lutetium 177Lu-PSMA-617 to target prostate-specific membrane antigen (PSMA), a protein that is abundantly expressed in 85-90 percent of metastasized prostate cancers. The small molecule binds to PSMA and delivers precise radiation therapy intended to shrink the cancer — even in cases in which cells have yet to form a visible tumor on a bone or CT scan.”
“A German multicenter study, initiated by the German Society of Nuclear Medicine, demonstrates that lutetium-177 (Lu-177)-labeled PSMA-617 is a promising new therapeutic agent for radioligand therapy (RLT) of patients with metastatic castration-resistant prostate cancer (mCRPC). The study is published in the January 2017 issue of the Journal of Nuclear Medicine and is the featured article.
“Prostate-specific membrane antigen (PSMA) is overexpressed in prostate cancer and even more so with castration-resistant disease. This makes development of new tracers for PSMA-targeted radionuclide therapies a promising treatment approach. Prostate cancer deaths are usually the result of mCRPC, and the median survival for men with mCRPC has been less than two years.”
“A molecular imaging biomarker is able to detect fast-growing primary prostate cancer and distinguish it from benign prostate lesions, addressing an unmet clinical need. The new research, published in the July 2015 issue of The Journal of Nuclear Medicine, is significant for patients with suspected prostate cancer that has not been confirmed by standard biopsy.
” ‘We were able to demonstrate in our research that PSMA PET imaging was more specific than MR imaging for detection of clinically significant high-grade prostate cancer lesions, and importantly was able to distinguish benign prostate lesions from primary prostate cancer, currently a difficult diagnostic imaging task,’ stated Steven P. Rowe, MD, PhD, resident at Johns Hopkins Medical Institutions in Baltimore, Md. ‘Additionally, this work demonstrated a direct correlation between PSMA PET radiotracer activity in prostate cancer and prostate adenocarcinoma aggressiveness (Gleason score).’ “
“A recent study reported in The Journal of Nuclear Medicine compared use of the novel Ga-68-PSMA-ligand PET/CT with other imaging methods and found that it had substantially higher detection rates of prostate-specific membrane antigen (PSMA) in patients with biochemical recurrence after radical prostatectomy. Discovering a recurrence early can strongly influence further clinical management, so it is especially noteworthy that this hybrid PSMA-ligand identified a large number of positive findings in the clinically important range of low PSA-values (<0.5ng/mL).
“According to the CDC, prostate cancer is the most common cancer among men in the United States, after non-melanoma skin cancer. While many men with prostate cancer die from other causes, prostate cancer remains one of the leading causes of cancer death among men of all races. Treatment and survival after recurrence depend on many factors, but early detection of the recurrence is certainly key.
“Matthias Eiber, MD, corresponding author of the study, noted, ‘The study is the first to examine this highly promising PET tracer in the use of a homogeneous patient collective consisting of only those with biochemical recurrence after radical prostatectomy. It found superb detection rates compared to other tracers, like choline, or imaging modalities, like MRI. For patients, this means that the referring urologist can receive earlier and more precise information about the site and extent of metastatic disease. Physicians will also be better able estimate whether a PSMA-PET scan might be useful in a specific setting.’ “