Preliminary results on response assessment using 68Ga-HBED-CC-PSMA PET/CT in patients with metastatic prostate cancer undergoing docetaxel chemotherapy

35 Background: Imaging-based response to systemic therapies in metastatic prostate cancer is still challenging. The aim of this study was to retrospectively investigate the association between Prostate-Specific Membrane Antigen (PSMA) expression changes on 68Ga PSMA PET/CT and the response to treatment following the start of taxane-based chemotherapies (docetaxel or cabazitaxel) in both metastatic hormonosensitive (mHSPC) and castration-resistant prostate cancer (mCRPC) patients. Methods: We retrospectively reviewed all 68Ga-PSMA-11 PET/CT scans performed at our institution from November 2014 to June 2020. We included mHSPC and mCRPC patients with a baseline 68Ga-PSMA PET/CT performed < 2 months before, and a second 68Ga-PSMA PET/CT performed < 3 months after docetaxel or cabazitaxel (with no modification in therapy between scans). The biological data was used to distinguish PSA-non-responders (increasing PSA or decreasing PSA by < 50% from pretherapy level) and PSA-responders (decreasing PSA > 50% following the start of therapy or the peak thereafter). The PSMA PET/CT response was assessed visually by two independent nuclear medicine physicians blinded to clinical data and patient outcomes. Patients were classified as PSMA-non-responders (≥1 new PSMA-expressing metastases, majority of PSMA-expressing metastases increasing in intensity, or stable PSMA-expression of the disease) or PSMA-responders (complete disappearance of pathologic PSMA uptake, or majority of PSMA-expressing metastases decreasing in intensity). Majority of lesions was defined as > 50% of registered lesions. Descriptive statistics and measures of associations (two-sided Fisher’s exact test and Phi coefficient) were calculated. Results: A total of 37 patients were included (8 mHSPC and 29 mCRPC), 21 patients under docetaxel and 16 cabazitaxel. All patients received at least 3 cycles [median 6 (range 3-10)]. The mean time (±standard deviation) between the first 68Ga-PSMA PET/CT and the start of therapy was 22±16 days. The mean time between the the last cycleand the second 68Ga-PSMA PET/CT was 36±27 days. PSA-response and PSMA-response were concordant in 95% of cases with 18 patients PSA/PSMA-non-responders and 17 PSA/PSMA-responders (Phi = 0.90, p = 0.0001). Two discordant patients presented with PSMA-response but PSA-non-response. No isolated PSMA flare was observed, as PSA-response was always associated with a decrease in PSMA-expression on the second PET/CT. Conclusions: This retrospective study suggests PSMA expression changes on PET/CT at least after 3 cycles of chemotherapy (docetaxel or cabazitaxel) are strongly associated with PSA response. No flare phenomenon was found at this evaluation. Prospective studies are needed to better define the potential role of PSMA-PET/CT in response assessment.

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18: PSMA-PET-Based Response Assessment of Metastatic Prostate Cancer Response to Radiotherapy: A Case Series

Radiotherapy and Oncology ◽

10.1016/s0167-8140(21)08896-4 ◽

2021 ◽

Vol 163 ◽

pp. S11

Author(s):

Aruz Mesci ◽

Mohammad Gouran-Savadkoohi ◽

Jeffrey Greenspoon ◽

Anil Kapoor ◽

Himanshu Lukka ◽

...

Keyword(s):

Prostate Cancer ◽

Metastatic Prostate Cancer ◽

Case Series ◽

Response Assessment ◽

Psma Pet

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Comparison of Tumor Heterogeneity Assessed with Textural Parameters in 68Ga-PSMA PET/CT and 177Lu-PSMA SPECT/CT in Patients with Metastatic Prostate Cancer

Biomedical Journal of Scientific & Technical Research ◽

10.26717/bjstr.2018.11.002161 ◽

2018 ◽

Vol 11 (5) ◽

Author(s):

Lara Schwarte

Keyword(s):

Prostate Cancer ◽

Tumor Heterogeneity ◽

Metastatic Prostate Cancer ◽

Psma Pet ◽

Pet Ct ◽

Textural Parameters

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Evaluation of [68Ga]Ga-PSMA-PET/CT in therapy response assessment of PSMA-targeted radionuclide therapy in patients with castration resistant prostate cancer

10.1055/s-0039-1683739 ◽

2019 ◽

Author(s):

J Kurth ◽

J Kretzschmar ◽

M Heuschkel ◽

G Kundt ◽

OW Hakenberg ◽

...

Keyword(s):

Prostate Cancer ◽

Radionuclide Therapy ◽

Therapy Response ◽

Response Assessment ◽

Targeted Radionuclide Therapy ◽

Castration Resistant Prostate Cancer ◽

Castration Resistant ◽

Psma Pet ◽

Pet Ct ◽

Therapy Response Assessment

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Prior PSMA PET-CT Imaging and Hounsfield Unit Impact on Tumor Yield and Success of Molecular Analyses from Bone Biopsies in Metastatic Prostate Cancer

Cancers ◽

10.3390/cancers12123756 ◽

2020 ◽

Vol 12 (12) ◽

pp. 3756

Author(s):

Minke Smits ◽

Kamer Ekici ◽

Samhita Pamidimarri Naga ◽

Inge M. van Oort ◽

Michiel J. P. Sedelaar ◽

...

Keyword(s):

Prostate Cancer ◽

Molecular Characterization ◽

Metastatic Prostate Cancer ◽

Ct Imaging ◽

Ct Guidance ◽

Prediction Tool ◽

Psma Pet ◽

Pet Ct ◽

Bone Biopsies ◽

Tumor Yield

Developing and optimizing targeted therapies in metastatic castration-resistant prostate cancer (mCRPC) necessitates molecular characterization. Obtaining sufficient tumor material for molecular characterization has been challenging. We aimed to identify clinical and imaging variables of imaging-guided bone biopsies in metastatic prostate cancer patients that associate with tumor yield and success in obtaining molecular results, and to design a predictive model: Clinical and imaging data were collected retrospectively from patients with prostate cancer who underwent a bone biopsy for histological and molecular characterization. Clinical characteristics, imaging modalities and imaging variables, were associated with successful biopsy results. In our study, we included a total of 110 bone biopsies. Histological conformation was possible in 84 of all biopsies, of which, in 73 of the 84, successful molecular characterization was performed. Prior use of PSMA PET-CT resulted in higher success rates in histological and molecular successful biopsies compared to CT or MRI. Evaluation of spine biopsies showed more often successful results compared to other locations for both histological and molecular biopsies (p = 0.027 and p = 0.012, respectively). Low Hounsfield units (HUs) and deviation (Dev), taken at CT-guidance, were associated with histological successful biopsies (p = 0.025 and p = 0.023, respectively) and with molecular successful biopsies (p = 0.010 and p = 0.006, respectively). A prediction tool combining low HUs and low Dev resulted in significantly more successful biopsies, histological and molecular (p = 0.023 and p = 0.007, respectively). Based on these results, we concluded that site selection for metastatic tissue biopsies with prior PSMA PET-CT imaging improves the chance of a successful biopsy. Further optimization can be achieved at CT-guidance, by selection of low HU and low Dev lesions. A prediction tool is provided to increase the success rate of bone biopsies in mCRPC patients, which can easily be implemented in daily practice.

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