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Adaptive Fractionation in Online Adaptive Stereotactic Radiotherapy for Abdominopelvic Lymph Node Oligometastases

NCT07415356 · Status: RECRUITING · Phase: NA · Type: INTERVENTIONAL · Enrollment: 25

Last updated 2026-02-17

No results posted yet for this study

Summary

Oligometastases, a state of cancer with up to five metastases, was traditionally treated with systemic treatments like chemotherapy. Treatment with stereotactic body radiotherapy (SBRT) showed a high local control and improved disease-free survival.

The use of SBRT also allows for the deferral of systemic treatment, thereby delaying its potential side effects. SBRT enables the delivery of a high dose to the tumor while minimizing the dose to organs at risk, reducing normal tissue damage, however, toxicity remains a potential issue in the abdominopelvic region, where lymph node oligometastases are often located near highly mobile, radiosensitive organs like the bowel.

Online adaptive radiotherapy is used to address this issue, adapting the treatment plan to the anatomy of the day. Unfortunately, adaptive radiotherapy results in longer treatment delivery times than conventional radiotherapy. This can potentially be countered by increasing the fraction dose and reducing the number of fractions if the patient anatomy allows it. This is convenient for the patient as it reduces the number of hospital visits, and it could also reduce the total workload for the hospital.

Therefore, there is not only a benefit of a reduction in toxicity by adaptive treatment, but also in reducing the total treatment time. This study aims to investigate if the number of adaptive fractions can be reduced by 30% for patients with abdominal or pelvic lymph node oligometastases.

Conditions

  • Lymph Node Oligometastases

Interventions

RADIATION

Online-Adaptive SBRT

The treatment will consist of online-adaptive SBRT using the ETHOS linear accelerator. The standard treatment will be 45 Gy in 5 fractions (45Gy/5Fx). If the patient anatomy allows, the number of planned fractions will be isotoxically reduced, keeping OAR and target dose goals biologically equivalent, to a minimum of 25 Gy in 1 fraction (25Gy/1Fx). For the adaptive treatment, daily HyperSight CBCT scans will be made, and the target and OAR contours will be automatically delineated and adjusted if necessary. If, during treatment, patient anatomy changes in such a way that fewer or more fractions are required than planned, changes can be made in the daily dose and number of remaining fractions. During and after treatment, a CBCT scan is made to verify the current treatment and improve future treatments.

Sponsors & Collaborators

  • Joost J. M. E. Nuyttens

    lead OTHER

Study Design

Allocation
NA
Purpose
TREATMENT
Masking
NONE
Model
SINGLE_GROUP

Eligibility

Min Age
18 Years
Sex
ALL
Healthy Volunteers
No

Timeline & Regulatory

Start
2025-02-27
Primary Completion
2026-02-05
Completion
2028-01-01

Countries

  • Netherlands

Study Locations

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Read the full study record

This page highlights key information. For complete eligibility criteria, study locations, investigator contacts, and the full protocol, visit the original record on ClinicalTrials.gov.

View NCT07415356 on ClinicalTrials.gov