MR-guided Adaptive Stereotactic Radiotherapy for Endometrial Cancer (MASTEC)

March 31, 2026 updated by: Radboud University Medical Center

MR-guided Adaptive Stereotactic Radiotherapy for Endometrial Cancer (MASTEC)

Rationale: External beam radiotherapy (EBRT) is an important cornerstone in treatment to reduce locoregional relapse in high(-intermediate) risk endometrial cancer (EC) patients. MR-guided adaptive radiotherapy (MGART) allows for more accurate delivery of radiation beams to the patients by visualizing and correcting for interfraction motion, with subsequent reduction of safety margins around the radiotherapy plan. Objective: The MASTEC study will investigate the safety of hypofractionated MR-guided adaptive radiotherapy in five fractions for elective pelvic nodal and vaginal vault irradiation in endometrial cancer.

Study design: Phase II multicentre intervention study Study population: Patients with endometrial cancer that receive adjuvant EBRT to the pelvic nodal areas and vaginal vault (with or without vaginal brachytherapy).

Intervention (if applicable): MR-guided adaptive radiotherapy (MGART) with reduced PTV margins, including 5 times 6Gy to the vaginal vault and pelvic nodal areas, 2 times a week .

Main study parameters/endpoints: The primary endpoint is acute gastrointestinal and genitourinary toxicity, scored by the Common Terminology Criteria Adverse Events version 6.0. Secondary endpoints are late gastrointestinal and genitourinary toxicity, quality of life and disease free survival; disease-specific survival; overall survival and metastasis-free survival.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

61

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 Contact

Study Contact Backup

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

In order to be eligible to participate in this study, a participant must meet all of the following criteria:

  • Women aged 18 years or older with histologically proven carcinoma of the endometrium, treated with curative hysterectomy with or without bilateral salpingo-oophorectomy. All histologies may be included (endometrioid, clear cell carcinoma, de-/undifferentiated carcinoma, carcinosarcoma, other non-endometrioid)

  • Candidate for adjuvant EBRT as decided by multidisciplinary tumour board, amongst others:

    • FIGO IB grade 3 endometrioid carcinoma
    • FIGO stage II endometrioid carcinoma
    • FIGO stage IIIA-C1 endometrioid carcinoma
    • FIGO IB-II clear cell carcinoma
    • FIGO IA-III carcinosarcioma
  • Patients receiving adjuvant systemic therapy are eligible when these therapies will not be administered concurrently
  • Patients receiving vaginal vault brachytherapy are eligible
  • Capable of giving informed consent

Exclusion criteria

A potential participant who meets any of the following criteria will be excluded from participation in this study:

  • Contra-indications for MRI according to the guidelines of the local department of Radiology, inability to lay on a treatment table for 45-60 minutes or severe claustrofobia
  • Presence of para-aortic lymph node metastases (FIGO stage IIIC2)
  • Prior pelvic radiotherapy
  • WHO performance score > 2

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

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Interventional arm
MR-guided stereotactic adaptive radiotherapy
Radiation: MR-guided adaptive radiotherapy (MGART) with reduced PTV margins, including 5 times 6Gy to the vaginal vault and pelvic nodal areas, 2 times a week
Patients will be treated with hypofractionated MR-guided adaptive radiotherapy up to 30Gy to the vaginal vault and pelvic nodal areas, contoured on T2W MRI and CT (slice thickness 3mm). Radiotherapy will not be performed on consecutive days. Radiotherapy will be performed by IMRT (7MV) on an MR-linac (Elekta Unity).

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Acute gastrointestinal and genitourinary toxicity (within 3 months after start of treatment)
Time Frame: 5 years after end of treatment

  1. Primary outcomes:

    Acute gastrointestinal toxicity: Maximum CTCAE v6.0 grade of GI toxicity within 90 days after treatment.

    Acute genitourinary toxicity: Maximum CTCAE v6.0 grade of GU toxicity within 90 days after treatment.

  2. Secondary Outcomes Late gastrointestinal toxicity: Maximum CTCAE v6.0 grade between 90 days and 5 years after treatment.

Late genitourinary toxicity: Maximum CTCAE v6.0 grade between 90 days and 5 years after treatment.

Acute vaginal toxicity: Maximum CTCAE v6.0 grade within 90 days after treatment.

Late vaginal toxicity: Maximum CTCAE v6.0 grade between 90 days and 5 years after treatment.

Quality of life: EORTC QLQ-C30 and QLQ-EN24 scores at 6 months and annually up to 5 years.

Locoregional disease-free survival: Time to locoregional recurrence or death. Distant disease-free survival: Time to distant metastasis or death. Overall survival: Time to death from any cause. Endometrial cancer-specific survival: Time to death due to endometrial cancer
5 years after end of treatment

Collaborators and Investigators

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

Sponsor

Radboud University Medical Center

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 (Estimated)

May 1, 2026

Primary Completion (Estimated)

June 1, 2028

Study Completion (Estimated)

March 1, 2033

Study Registration Dates

First Submitted

March 18, 2026

First Submitted That Met QC Criteria

March 31, 2026

First Posted (Actual)

April 7, 2026

Study Record Updates

Last Update Posted (Actual)

April 7, 2026

Last Update Submitted That Met QC Criteria

March 31, 2026

Last Verified

November 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • NL-011073 (Registry Identifier: CMO Portal)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

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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