ASTRA Study: Circulating Tumor Cells in Blood of Patients With High-Grade Serous Ovarian Cancer

February 23, 2026 updated by: Institute of Oncology Ljubljana

ASTRA: Circulating Tumor Cells in Blood of Patients With High-Grade Serous Ovarian Cancer-Morphology, Immunophenotype, and Association With Clinical Outcomes

High-grade serous ovarian cancer is typically diagnosed at an advanced stage and remains associated with poor long-term survival. Reliable biomarkers for predicting disease course and treatment response are still limited.

Circulating tumor cells (CTCs) are malignant cells that detach from the primary tumor and enter the bloodstream. Their presence has been associated with disease progression and prognosis in several malignancies, including ovarian cancer. However, data on the morphological characteristics, immunophenotype, and clinical relevance of CTCs in high-grade serous ovarian cancer remain limited.

The ASTRA study evaluates the number and characteristics of circulating tumor cells in peripheral blood samples obtained from patients with high-grade serous ovarian cancer. The study examines CTC count, presence of CTC clusters and megakaryocytes, and immunophenotypic marker expression, and explores associations between CTC findings and clinical parameters and outcomes.

Results from this study may contribute to improved understanding of circulating tumor cells in ovarian cancer and support the development of liquid biopsy approaches for prognostic assessment and disease monitoring.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

This prospective, single-arm interventional diagnostic study evaluates circulating tumor cells (CTCs) in patients with high-grade serous ovarian cancer (HGSC). The study is designed to characterize the morphological and immunophenotypic features of CTCs and to assess their association with clinical and prognostic parameters.

Eligible participants include adult women with histologically confirmed high-grade serous ovarian cancer (FIGO stage III or IV) undergoing first-line platinum-based systemic therapy. As part of the study protocol, an additional 10 mL peripheral blood sample is collected prior to initiation of systemic therapy. In participants with detectable CTCs at baseline, a second additional 10 mL blood sample is collected before cycle 4 of systemic therapy to evaluate treatment-related changes in CTC count and characteristics.

Circulating tumor cells are isolated using the Parsortix size-based microfluidic system, which preserves cellular morphology. Isolated cells are processed into cytospin preparations and analyzed using cytology staining, immunocytochemistry, and immunofluorescence methods. CTCs are evaluated for number, presence of single cells and clusters, and expression of epithelial and mesenchymal markers. Megakaryocytes and other non-tumor cells are assessed to ensure accurate cell classification.

Clinical data, including tumor stage, laboratory parameters (e.g., CA125 and immune-inflammatory indices), treatment information, and outcome data, are obtained from medical records. Progression-free survival and overall survival are assessed using clinical follow-up data and the national cancer registry.

Statistical analyses include descriptive statistics, correlation analyses between CTC findings and clinical parameters, and survival analyses using Kaplan-Meier methods and multivariable Cox regression models.

This study provides detailed insight into circulating tumor cells in high-grade serous ovarian cancer and explores their potential role as prognostic biomarkers and tools for future clinical and translational research.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
30

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Slovenia
      • Ljubljana, Slovenia, 1000
        • Institute of Oncology Ljubljana

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Female patients aged 18 years or older.

    • Histologically confirmed high-grade serous ovarian cancer.
    • FIGO stage III or IV disease.
    • Indication for first-line platinum-based systemic therapy.
    • ECOG/WHO performance status 0-2.
    • Ability to provide peripheral blood samples.
    • Written informed consent obtained prior to participation.

Exclusion Criteria:

  • Presence of another active malignancy.
  • Any condition that, in the opinion of the investigators, could interfere with study participation or interpretation of results.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Diagnostic
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Peripheral Blood Collection for CTC Analysis
Adult women with histologically confirmed high-grade serous ovarian cancer (FIGO stage III or IV) undergoing standard-of-care first-line platinum-based systemic therapy provide an additional 10 mL peripheral blood sample for circulating tumor cell (CTC) isolation and analysis at baseline. In participants with detectable CTCs at baseline, a second additional 10 mL blood sample is collected before cycle 4 of systemic therapy to assess treatment-related changes.
Other: Peripheral Blood Collection for CTC Isolation and Analysis
Collection of an additional 10 mL peripheral blood sample for isolation and characterization of circulating tumor cells using the Parsortix size-based microfluidic system, followed by cytological and immunophenotypic analysis.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Number of Circulating Tumor Cells (CTCs) per 10 mL of Peripheral Blood
Time Frame: Baseline (prior to initiation of systemic therapy)
Total number of circulating tumor cells detected in 10 mL of peripheral blood using the Parsortix size-based isolation system. Results are reported as number of CTCs per participant.
Baseline (prior to initiation of systemic therapy)

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Presence of Circulating Tumor Cell (CTC) Clusters
Time Frame: Baseline (prior to initiation of systemic therapy)
Presence of circulating tumor cell clusters identified in 10 mL of peripheral blood following isolation and cytological evaluation.
Baseline (prior to initiation of systemic therapy)
Number of Megakaryocytes Detected per 10 mL of Peripheral Blood
Time Frame: Baseline (prior to initiation of systemic therapy)
Number of megakaryocytes detected in 10 mL of peripheral blood during cytological evaluation following CTC isolation.
Baseline (prior to initiation of systemic therapy)
Proportion of Circulating Tumor Cells Expressing Immunophenotypic Markers
Time Frame: Baseline and pre-cycle 4 assessment (up to 12 weeks)
Proportion of isolated circulating tumor cells expressing predefined epithelial or mesenchymal markers as assessed by immunocytochemistry and immunofluorescence.
Baseline and pre-cycle 4 assessment (up to 12 weeks)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Institute of Oncology Ljubljana

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
January 1, 2024

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
December 31, 2025

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 31, 2025

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
February 4, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
February 23, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
February 27, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
February 27, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
February 23, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
February 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • OIL_ASTRA_2023
  • ERID-KSOPR-0088/2023 (Other Identifier: Clinical Research Unit, Institute of Oncology Ljubljana)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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