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

Completed

Conditions

Intervention / Treatment

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

Interventional

Enrollment (Actual)

30

Phase

  • 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

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
Intervention / Treatment
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

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

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

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)

January 1, 2024

Primary Completion (Actual)

December 31, 2025

Study Completion (Actual)

December 31, 2025

Study Registration Dates

First Submitted

February 4, 2026

First Submitted That Met QC Criteria

February 23, 2026

First Posted (Actual)

February 27, 2026

Study Record Updates

Last Update Posted (Actual)

February 27, 2026

Last Update Submitted That Met QC Criteria

February 23, 2026

Last Verified

February 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID 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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