Abstract 4058
Background
For individual treatment planning in patients with metastatic castration resistant prostate cancer (mCRPC), molecular analyses are increasingly used. As most patients have bone only disease, bone biopsies are often the only source for tumour tissue. However, the success rate of computed tomography (CT)-guided bone biopsies for molecular analyses in mCRPC patients is only 36.5-44%. Positron emission tomography (PET) using 68Ga-PSMA is a promising tool to increase the success rate of bone biopsies for molecular analyses in mCRPC patients.
Methods
In this multicenter study, the success rate of 68Ga-PSMA guided bone biopsies for molecular diagnostics was retrospectively evaluated in a subset of mCRPC patients who underwent a bone biopsy for whole-genome DNA sequencing within the CPCT-02 study (NCT01855477). To evaluate whether biopsies were obtained from a 68Ga-PSMA positive lesion, rigid body image registration of 68Ga-PSMA PET/CT and interventional CT was performed. This technique provided volume of interest (VOI) based quantification of 68Ga-PSMA uptake at the exact biopsy site. In addition, the potential impact of molecular analyses on clinical decision making was evaluated.
Results
Sixty-nine 68Ga-PSMA-guided biopsies were eligible for primary analysis. Based on tumor percentage ≥ 30%, 70% of 68Ga-PSMA-guided biopsies was eligible for molecular analyses. At biopsy sites with positive, inconclusive or negative 68Ga-PSMA uptake, tumour percentage was ≥ 30% in 73%, 55% and 36% of the biopsies, respectively (p = 0.0850). At sites of biopsies with a tumour percentage ≥ 30%, standardized uptake value (SUV)max and SUVmean of 68Ga-PSMA were significantly higher (p = 0.0260 and p = 0.0129 respectively), whereas Hounsfield units (HU)mean and HUmax on CT were significantly lower (p = 0.0189 and p = 0.0494 respectively). Molecular analyses identified potentially targetable aberrations including PTEN loss, AR amplifications, and BRCA variants.
Conclusions
68Ga-PSMA PET/CT is a useful technique to improve the success rate of CT-guided bone biopsies for molecular analyses in mCRPC patients. Successful bone biopsies for molecular analyses can improve individual treatment planning by detecting targetable mutations.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
R. de Wit: Advisory / Consultancy, Speaker Bureau / Expert testimony, Research grant / Funding (institution): Sanofi; Advisory / Consultancy, Speaker Bureau / Expert testimony: Merck; Advisory / Consultancy, Research grant / Funding (institution): Bayer; Advisory / Consultancy: Roche; Advisory / Consultancy: Janssen; Advisory / Consultancy: Clovis. N. Mehra: Advisory / Consultancy, Research grant / Funding (institution): Astellas; Advisory / Consultancy, Research grant / Funding (institution): Janssen; Research grant / Funding (institution): Pfizer; Advisory / Consultancy, Research grant / Funding (institution): Roche; Advisory / Consultancy, Research grant / Funding (institution): Sanofi Genzyme; Advisory / Consultancy: MSD; Advisory / Consultancy: BMS; Advisory / Consultancy: Bayer. A.A.M. Van der Veldt: Honoraria (institution), Advisory / Consultancy: BMS; Honoraria (institution), Advisory / Consultancy: MSD; Honoraria (institution), Advisory / Consultancy: Roche; Honoraria (institution), Advisory / Consultancy: Novartis; Honoraria (institution), Advisory / Consultancy: Pierre Fabre; Honoraria (institution), Advisory / Consultancy: Pfizer; Honoraria (institution), Advisory / Consultancy: Sanofi; Honoraria (institution), Advisory / Consultancy: Ipsen. M.P. Lolkema: Research grant / Funding (institution): JNJ; Research grant / Funding (institution): Astellas. All other authors have declared no conflicts of interest.
Resources from the same session
2115 - Preclinical in vivo screening to predict responder patients depend on EGFR status
Presenter: Yejin Kim
Session: Poster Display session 3
Resources:
Abstract
3349 - Interplay between miR-17-5p and MALAT-1 Shapes The Cytokine Storm in Triple Negative Breast Cancer (TNBC) Tumor Microenvironment
Presenter: Raghda Soliman
Session: Poster Display session 3
Resources:
Abstract
4014 - Clinical verification on the relationship between lipid metabolism and the immune microenvironment of breast cancer
Presenter: Wataru Goto
Session: Poster Display session 3
Resources:
Abstract
4158 - The clinical and transcriptional signatures of human CD204 reveal an applicable marker for tumor associated macrophage in breast cancer
Presenter: Yunjie He
Session: Poster Display session 3
Resources:
Abstract
5392 - Activated effector T cells co-expressing multiple inhibitory receptors (IRs) are enriched in the tumor immune microenvironment in high grade serous ovarian cancer (HGSOC)
Presenter: Alice Bergamini
Session: Poster Display session 3
Resources:
Abstract
2617 - Oncolytic reovirus as a new anti-tumor strategy in castration resistant prostate cancer
Presenter: Yunlim Kim
Session: Poster Display session 3
Resources:
Abstract
2995 - Dysregulation of helper T lymphocytes in esophageal squamous cell carcinoma (ESCC) patients is highly associated with aberrant production of miR-21
Presenter: Ali Memarian
Session: Poster Display session 3
Resources:
Abstract
3597 - Myeloid derived suppressor cells but not regulatory T cells are associated with adaptive immunity and clinical outcomes in anal squamous cell carcinoma
Presenter: Christophe Borg
Session: Poster Display session 3
Resources:
Abstract
3430 - Evaluation of immune responses among responders (R) and non-responders (non-R) in a humanized mouse model with colorectal cancer (CRC) xenografts treated with combination immunotherapy
Presenter: Juan Marín Jiménez
Session: Poster Display session 3
Resources:
Abstract
1995 - ¬¬Advanced melanoma patients with high CD16+ macrophages have better response and survival to anti-PD-1 based immunotherapy
Presenter: Hansol Lee
Session: Poster Display session 3
Resources:
Abstract