Evaluation of the Technical Feasibility of Testing ct DNA for Homologous Recombination Gene Variants in Metastatic Prostate Cancer.

Study Overview
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Brief Summary
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Evaluation of technical feasibility for Homologous Recombination (HR) genes variants research on circulating tumor DNA (ctDNA) from plasma and urine of patients with a metastatic prostate cancer.

Detailed Description
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The benefit of PARPi has been well established for ovarian (SOLO-1 study) and prostate cancer (PROFOUND study) with defects in the Homologous Recombination Repair (HRR) system due to BRCA1 or BRCA2 variants. Somatic variants in HRR genes are currently researched by Next Generation Sequencing (NGS). However, in metastatic prostate cancer, using formalin-fixed and paraffin-embedded (FFPE) samples, failure rate is around 30 % according to our retrospective datas, in agreement with the data of the PROFOUND study, highlighting a real pre-analytical matter when FFPE samples are used for NGS testing. Research of such alterations on circulating tumor DNA (ctDNA) extracted from plasma or urine could be a promising alternative test.

Official Title
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Evaluation of the Technical Feasibility of Testing Circulating Tumour DNA for Homologous Recombination Gene Variants in Metastatic Prostate Cancer.

Conditions
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Circulating Tumor DNA, Metastatic Prostate Cancer

Intervention / Treatment
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* Other: Blood sample
* Other: Urine sample


Participation Criteria
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Eligibility Criteria
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Inclusion criteria Age > 18 years Metastatic prostate cancer Archived tissue sample available for testing for somatic variants of HRR genes (including BRCA1/BRCA2) Free, informed and signed consent for research Non inclusion criteria Refusal of blood and urine collection Patient cognitively incapable of signing consent to participate in this study Patient under guardianship or curatorship

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| adult patients with metastatic prostate cancer<br> | Other: Blood sample<br>* 2 tubes Cell free DNA are taken during a blood sample already planned in the patient's care.<br>Other: Urine sample<br>* Urine sample is taken during the consultation carried out for the patient's care<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Circulating plasma tumour DNA | search for somatic variants of HRR genes (including BRCA1/BRCA2) | Baseline | 
| Circulating urine tumour DNA | search for somatic variants of HRR genes (including BRCA1/BRCA2) | Baseline | 
| FFPE tissue | search for somatic variants of HRR genes (including BRCA1/BRCA2) | Baseline | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Prostate cancer, ctDNA, HR genes