18F-DCFPyL Imaging as a Method to Assess Treatment Response to Stereotactic Body Radiation Therapy

Background:

Radiotherapy is a highly effective treatment for localized prostate cancer; however,

recurrence is more common in patients with unfavorable intermediate and high-risk

prostate cancer, and is usually diagnosed by rising prostate specific antigen (PSA -

biochemical failure).

Early identification of disease persistence or recurrence before meeting criteria of

biochemical failure may allow effective potentially curative salvage treatment, but

identification of local recurrence or persistence at early stages is challenging. CT

imaging is relatively insensitive at localizing recurrence, while MRI is more sensitive

for local recurrence but is non-specific.

Prostate specific membrane antigen (PSMA) targeted PET imaging was recently FDA approved

for imaging men with suspected prostate cancer metastases who are potentially curable by

radiation or surgery. PSMA based imaging has been used in prospective trials to define

extent of disease and to alter radiation treatment volumes.

18F-DCFPyL, a second generation PSMA PET agent that binds with high affinity to PSMA yet

clears rapidly from the blood pool, has recently been approved by the FDA as a method to

stage high risk cancer and detect recurrent disease.

Primary Objective:

To define 18F-DCFPyL PET/CT imaging response in participants with localized prostate

cancer after treatment with stereotactic body radiation therapy (SBRT) with or without

androgen deprivation therapy (ADT).

Eligibility:

Biopsy proven localized prostate cancer in whom prostate SBRT with or without ADT is

appropriate therapy

Must have at least 1 MRI detected, biopsy proven site of prostate cancer.

ECOG 0-2

Design:

This is a single center, prospective study aimed at recruiting the following cohorts:

Up to 40 evaluable participants with presumed localized prostate cancer (intermediate or

high risk) scheduled to undergo radiotherapy with systemic androgen deprivation therapy.

Up to 40 evaluable participants with presumed localized prostate cancer (intermediate or

high risk) scheduled to undergo SBRT without androgen deprivation therapy.

Up to 20 evaluable participants with presumed localized prostate cancer (intermediate or

high risk) scheduled to undergo radiotherapy with localized androgen deprivation therapy.

Participants receiving neoadjuvant androgen deprivation therapy will undergo a second

18F-DCFPyL PET/CT and multiparametric MRI (mpMRI) at 8 weeks after initiation of ADT but

before SBRT.

All participants will undergo 18F-DCFPyL PET/CT and mpMRI 6 months following completion

of SBRT and at recurrence, if applicable.

Participants will be followed for up to 2 years after completion of SBRT to evaluate

longitudinal quality of life and biochemical control.