Impact of 68Ga-PSMA-PET imaging on target volume definition and guidelines in radiation oncology - a patterns of failure analysis in patients with primary diagnosis of prostate cancer

Abstract Background Prostate Membrane Specific Antigen (PSMA) positron emission tomography (PET) and multiparametric MRI (mpMRI) have shown high accuracy in identifying recurrent lesions after definitive treatment in prostate cancer (PCa). In this study, we aimed to outline patterns of failure in a group of post-prostatectomy patients who received adjuvant or salvage radiation therapy (PORT) and subsequently experienced biochemical recurrence, using 18F-PSMA PET/CT and mpMRI. Methods PCa patients with biochemical failure post-prostatectomy, and no evident site of recurrence on conventional imaging, were enrolled on two prospective trials of first and second generation 18F-PSMA PET agents (18F-DCFBC and 18F-DCFPyL) in combination with MRI between October 2014 and December 2018. The primary aim of our study is to characterize these lesions with respect to their location relative to previous PORT field and received dose. Results A total of 34 participants underwent 18F-PSMA PET imaging for biochemical recurrence after radical prostatectomy and PORT, with 32/34 found to have 18F-PSMA avid lesions. On 18F-PSMA, 17/32 patients (53.1%) had metastatic disease, 8/32 (25.0%) patients had locoregional recurrences, and 7/32 (21.9%) had local failure in the prostate fossa. On further exploration, we noted 6/7 (86%) of prostate fossa recurrences were in-field and were encompassed by 100% isodose lines, receiving 64.8–72 Gy. One patient had marginal failure encompassed by the 49 Gy isodose. Conclusions 18F-PSMA PET imaging demonstrates promise in identifying occult PCa recurrence after PORT. Although distant recurrence was the predominant pattern of failure, in-field recurrence was noted in approximately 1/5th of patients. This should be considered in tailoring radiotherapy practice after prostatectomy. Trial registrationwww.clinicaltrials.gov, NCT02190279 and NCT03181867. Registered July 12, 2014, https://clinicaltrials.gov/ct2/show/NCT02190279 and June 8 2017, https://clinicaltrials.gov/ct2/show/NCT03181867.

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Variation of clinical target volume definition in three-dimensional conformal radiation therapy for prostate cancer

International Journal of Radiation Oncology*Biology*Physics ◽

10.1016/s0360-3016(99)00090-5 ◽

1999 ◽

Vol 44 (4) ◽

pp. 931-935 ◽

Cited By ~ 60

Author(s):

Richard K Valicenti ◽

John W Sweet ◽

Walter W Hauck ◽

Richard S Hudes ◽

Tony Lee ◽

...

Keyword(s):

Prostate Cancer ◽

Radiation Therapy ◽

Clinical Target Volume ◽

Three Dimensional ◽

Target Volume ◽

Conformal Radiation Therapy ◽

Target Volume Definition

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Target Volume Definition in Primary Prostate Cancer Radiotherapy

Radiotherapy in Prostate Cancer - Medical Radiology ◽

10.1007/174_2014_958 ◽

2014 ◽

pp. 33-39

Author(s):

Dirk Böhmer

Keyword(s):

Prostate Cancer ◽

Target Volume ◽

Cancer Radiotherapy ◽

Target Volume Definition ◽

Primary Prostate Cancer ◽

Prostate Cancer Radiotherapy

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64Cu-PSMA-BCH: A New Radiotracer for Delayed PET Imaging of Prostate Cancer

10.21203/rs.3.rs-238776/v1 ◽

2021 ◽

Author(s):

Teli Liu ◽

Chen Liu ◽

Zhongyi Zhang ◽

Ning Zhang ◽

Xiaoyi Guo ◽

...

Keyword(s):

Prostate Cancer ◽

Pet Imaging ◽

Radiation Dosimetry ◽

Whole Body ◽

Post Injection ◽

Human Organ ◽

Fine Needle ◽

Fine Needle Aspirates ◽

Psma Pet

Abstract PurposeDevelop a 64Cu labeled radiopharmaceutical targeting prostate specific membrane antigen (PSMA) and investigate its application for prostate cancer imaging. Methods64Cu-PSMA-BCH was prepared and investigated for stability, PSMA specificity and micro-PET imaging. With the approval of Ethics Committee of Beijing Cancer Hospital (No. 2017KT97), PET/CT imaging in 4 patients with suspected prostate cancer was performed and the radiation dosimetry was estimated. Then, PSMA PET-ultrasound image-guided biopsies were performed on 3 patients and the fine needle aspirates were further performed for autoradiography and immunohistochemistry analysis. Results64Cu-PSMA-BCH was prepared with high radiochemical yield and stability. In vivo study showed higher uptake in PSMA (+) 22Rv1 cells than PSMA (-) PC-3 cells (5.59±0.36 and 1.97±0.22 IA%/106 cells at 1 h). It accumulated in 22Rv1 tumor with increasing radioactivity uptake and T/N ratios from 1 h to 24 h post-injection. In patients with suspected prostate cancer, SUVmax and T/N ratios increased within 24 h post-injection. Compared with image at 1 h post-injection, more tumor lesions were detected at 4 h and 24 h post-injection. The human organ radiation dosimetry showed gallbladder wall was most critical, liver and kidneys were followed, and the whole-body effective dose was 0.0292 mSv/MBq. Two fine needle aspirates obtained by PET-ultrasound guided targeted biopsy showed high radioactive signal by autoradiography, with 100% PSMA expression in cytoplasm and 30% expression in nucleus. Conclusion64Cu-PSMA-BCH was PSMA specific and showed high stability in vivo with lower uptake in liver than 64Cu-PSMA-617. Biodistribution in mice and PCa patients showed similar profile compared with other PSMA ligands and it was safe with moderate effective dosimetry. The increased tumor uptake and T/N ratios by delayed imaging may facilitate the detection of small lesions and guiding targeted biopsies.

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