1. Kumar Das, Dibash PhD

Article Content

According to the American Cancer Society, it is estimated that nearly 250,000 new cases of prostate cancer will be diagnosed, and more than 34,000 men will die of the disease in 2021. Additionally, despite advances in radiation treatment, prostate cancer will recur in up to 30 percent of patients after initial treatment.

prostate cancer. pro... - Click to enlarge in new windowprostate cancer. prostate cancer

Typically, androgen deprivation therapy (ADT) is used to treat recurrent prostate cancer, but it may create adverse side effects for many patients and also lose effectiveness over time. The ability to determine the extent and location of recurrent prostate cancer can help facilitate improved personalized patient management.


Earlier this year, the FDA approved the prostate-specific membrane antigen (PSMA)-targeted positron emission tomography (PET) imaging agent 18F-DCFPyL (also known as piflufolastat F 18) for identifying suspected metastasis or recurrence of prostate cancer. 18F-DCFPyL was approved based on the findings of the Phase III CONDOR trial (NCT03739684) and the Phase II/III OSPREY trial (NCT02981368), which demonstrated the improved sensitivity and accuracy of 18F-DCFPyL to identify and locate the disease.


More recently, at the American Urological Association 2021 Annual Meeting, Andrei Iagaru, MD, and colleagues presented the results of their work evaluating 18F-DCFPyL PET/CT in a single-center study for detecting recurrent lesions in prostate cancer patients with biochemical recurrence (BCR) (J Urol 2021;


In total, 223 patients (49-91 years old, mean +/-SD: 69.8+/-8.1) were prospectively enrolled with BCR (prostate-specific antigen [PSA] median 2.0 ng/mL, range 0.12-698.4) after primary definitive treatment with prostatectomy (72%), radiotherapy (28%), or both (25%). The 18F-DCFPyL positive lesions compatible with prostate cancer were evaluated by two independent readers. Patients with possible extra-pelvic oligometastases were identified.


"18F-DCFPyL PET/CT had an overall positivity rate of 84 percent across all PSA levels, which increased with PSA levels (ng/mL): 62 percent (PSA <0.5), 77 percent (0.5 <=PSA <1), 90 percent (1 <=PSA <2), 92 percent (2 <=PSA <5), and 96 percent (PSA >=5), respectively," noted the authors.


Further, the researchers evaluated the detection rate of 18F-DCFPyL after prostatectomy based on PSA doubling time. 18F-DCFPyL PET/CT had a higher positivity rate in patients with shorter PSA doubling time (PSADT) (93% in PSADT 0-3 months vs. 63% in PSADT >12 months, P<0.01). Higher positivity rate was also observed in prostatectomy patients with high Gleason score (97% in Gleason score 9-10 versus 82% in Gleason score 8 vs. 73% in Gleason score 7 and 67% in Gleason score 6, P<0.01). There was no difference of 18F-DCFPyL positivity rate observed in post-radiation patients with different PSADT or Gleason scores.


Following 18F-DCFPyL PET/CT, 46 percent on targeted radiotherapy, 28 percent on ADT, 8 percent on surveillance, and 18 percent considered "other" made changes to their management of the disease after a positive scan, compared to 24 percent, 7 percent, and 69 percent, respectively, who made changes to their management of the disease after a negative scan.


Oncology Times connected with Andrei Iagaru, MD, Professor of Radiology-Nuclear Medicine and Chief of the Division of Nuclear Medicine and Molecular Imaging at Stanford Health Care, to further discuss 18F-DCFPyL PET/CT for prostate cancer.


Oncology Times: Despite advances in radiation treatment, prostate cancer will recur in up to 30 percent of patients after initial treatment. There is currently no consensus on how best to treat reoccurrence. Why is that so?


Iagaru: "Despite the recent advances in diagnosis and therapy, we are only scratching the surface of the iceberg. Much more work is needed to make inroads in this area. But we now have better radiopharmaceuticals and instrumentation (digital PET and single-photon emission computed tomography [SPECT] combined with CT and MRI), so we are ideally positioned to make nuclear medicine a big player in the prostate cancer arena."


Oncology Times: What are your thoughts regarding the use of 18F-DCFPyL in your practice? What do you think it means to patients?


Iagaru: "We had access to 18F-DCFPyL through a research access program in ~250 patients since 2018 already. It is a game-changing agent that the referring physicians already use in the clinical management of their patients. We have a workflow to use 18F-DCFPyL both prior to definitive treatment using PET/MRI and at biochemical recurrence using PET/CT. Our fleet of PET/CT and PET/MRI scanners is all digital, which greatly enhances the ability to identify small lesions and early recurrence."


Oncology Times: Might there be utility for this diagnostic tool for lower-risk prostate cancer?


Iagaru: "Currently 18F-DCFPyL PET/CT holds great potential to be a 'one-stop shop' diagnostic tool in the workup of BCR prostate cancer. Perhaps there may be utility for surveillance and biopsy guidance."


Oncology Times: The NCCN panel has recognized the increased sensitivity and specificity of PSMA-PET tracers, compared to conventional imaging (CT, MRI), for detecting micrometastatic disease at both initial staging and biochemical recurrence. Is there potential to combine this PMSA PET imaging agent with MRI or spectroscopy to improve detection and anatomic definition?


Iagaru: "First, PET is as conventional as CT, MRI, or bone scans. There is nothing unconventional about it. The jury is still out about PSMA PET replacing CT and bone scans, in my opinion, but it has a clear advantage that remains to be validated in larger prospective studies in the U.S. 18F-DCFPyL PET/MRI is ideal for prostate biopsy guidance, as well as for evaluation prior to high-intensity focused ultrasound, HDR brachytherapy, and prostatectomy."


Dibash Kumar Das is a contributing writer.