Randomized prospective phase III trial of ⁶⁸Ga-PSMA-11 PET/CT molecular imaging for prostate cancer salvage radiotherapy planning [PSMA-SRT]

Journal Article · Mon Jan 07 00:00:00 EST 2019 · BMC Cancer

DOI:https://doi.org/10.1186/s12885-018-5200-1· OSTI ID:1611772

Calais, Jeremie ^[1]; Czernin, Johannes ^[2]; Fendler, Wolfgang P. ^[3]; Elashoff, David ^[2]; Nickols, Nicholas G. ^[4]

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1. Univ. of California, Los Angeles, CA (United States); DOE/OSTI
2. Univ. of California, Los Angeles, CA (United States)
3. Univ. of California, Los Angeles, CA (United States); Univ. Hospital, Essen (Germany)
4. Univ. of California, Los Angeles, CA (United States); VA Greater Los Angeles Healthcare System, Los Angeles, CA (United States)

Salvage radiotherapy (SRT) for prostate cancer (PCa) recurrence after prostatectomy offers long-term biochemical control in about 50–60% of patients. SRT is commonly initiated in patients with serum PSA levels < 1 ng/mL, a threshold at which standard-of-care imaging is insensitive for detecting recurrence. As such, SRT target volumes are usually drawn in the absence of radiographically visible disease. ⁶⁸Ga-PSMA-11 (PSMA) PET/CT molecular imaging is highly sensitive and may offer anatomic localization of PCa biochemical recurrence. However, it is unclear if incorporation of PSMA PET/CT imaging into the planning of SRT could improve its likelihood of success. The purpose of this trial is to evaluate the success rate of SRT for recurrence of PCa after prostatectomy with and without planning based on PSMA PET/CT.

Methods

We will randomize 193 patients to proceed with standard SRT (control arm 1, n = 90) or undergo a PSMA PET/CT scan (free of charge for patients) prior to SRT planning (investigational arm 2, n = 103). The primary endpoint is the success rate of SRT measured as biochemical progression-free survival (BPFS) after initiation of SRT. Biochemical progression is defined by PSA ≥ 0.2 ng/mL and rising. The randomization ratio of 1:1.13 is based on the assumption that approximately 13% of subjects randomized to Arm 2 will not be treated with SRT because of PSMA-positive extra-pelvic metastases. These patients will not be included in the primary endpoint analysis but will still be followed. The choice of treating the prostate bed alone vs prostate bed and pelvic lymph nodes, with or without androgen deprivation therapy (ADT), is selected by the treating radiation oncologist. The radiation oncologist may change the radiation plan depending on the findings of the PSMA PET/CT scan. Any other imaging is allowed for SRT planning in both arms if done per routine care. Patients will be followed until either one of the following conditions occur: 5 years after the date of initiation of randomization, biochemical progression, diagnosis of metastatic disease, initiation of any additional salvage therapy, death.

Discussion

This is the first randomized phase 3 prospective trial designed to determine whether PSMA PET/CT molecular imaging can improve outcomes in patients with PCa early BCR following radical prostatectomy.

• Research Organization: Univ. of California, Los Angeles, CA (United States)
• Sponsoring Organization: German Research Foundation (DFG); National Institutes of Health (NIH); USDOE Office of Science (SC)
• Grant/Contract Number: SC0012353
• OSTI ID: 1611772
• Journal Information: BMC Cancer, Journal Name: BMC Cancer Journal Issue: 1 Vol. 19; ISSN 1471-2407
• Publisher: BioMed Central
• Country of Publication: United States
• Language: English

Related Subjects

60 APPLIED LIFE SCIENCES
PET/CT
PSMA
oncology
prostate cancer
randomized phase 3 trial
salvage radiation therapy