MRI guided adaptive brachytherapy (BT) represents the gold standard in the treatment of gynecological cancers. Commercially available standard MRI compatible applicators for BT of gynecological cancers don't always allow for optimal target volume coverage. Three-dimensional (3D) printed technology enables versatile possibilities of improvement of standard applicators and development of novel applicators with better coverage of the target volume. The purpose of this study is to implement and assess 3D printing technology as an instrument for designing and manufacturing applicators for individualized BT of gynecological cancers.
Patients with locoregionally gynecological cancers will be included in this single-institution, non-randomized, one-arm study. All patients will receive 45-50 Gy external beam radiotherapy (EBRT) with intensity-modulated radiotherapy/volumetric-modulated arc therapy (IMRT/VMAT) technique, 1.8-2 Gy/fraction +/- concurrent cisplatin based chemotherapy. First BT with commercially available standard applicators (tandem with ring +/- parallel needles or vaginal cylinder) will be carried out. MRI with applicator in situ will be performed, high-risk clinical target volume (CTV-HR) and organs at risk (OAR) will be delineated and treatment planning will be conducted. In the case of large gynecological cancer and suboptimal target coverage at BT (V100 ≤ 90%, D98 ≤ 80%, D90 ≤ 100%, D100 ≤ 60%) a preplan will be performed as the basis for the 3D applicator modelling. The next BT application will be performed with an individually designed 3D printed applicator. Dose-volume characteristics of the following treatment plans will be compared: the preplan, the plan with standard and the plan with individual 3D printed applicator. The primary objective of the study is to determine the improvement of dose-volume parameters with the use of 3D printed individual applicators in advanced gynecological cancer.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
TREATMENT
Masking
NONE
Enrollment
50
An individualized MRI-compatible brachytherapy applicator is designed based on the participant's anatomy, tumor location, high-risk clinical target volume, and preliminary treatment plan. The applicator is manufactured using 3D-printing technology and may include an add-on cap for oblique needles, an individualized Vienna-type applicator, or an individualized vaginal cylinder for intracavitary and interstitial brachytherapy. The aim is to improve target volume coverage while respecting dose constraints for organs at risk.
Institute of Oncology Ljubljana
Ljubljana, Slovenia
Improvement in High-Risk Clinical Target Volume Coverage
Dose-volume parameters for the high-risk clinical target volume (HR-CTV) will be compared between treatment plans generated with a standard brachytherapy applicator and an individualized 3D-printed applicator within the same participant. Evaluated parameters include D90, D98, D100, and V100. The absolute and relative improvement achieved with the individualized applicator will be reported.
Time frame: During brachytherapy treatment planning, before delivery of the planned brachytherapy dose
Number of Participants With Grade 3 or Higher Treatment-Related Toxicity
Treatment-related toxicity involving the bladder, rectum, bowel, and vagina will be assessed using the Common Terminology Criteria for Adverse Events, version 3.0. The number and percentage of participants with new or worsening grade 3 or higher toxicity will be reported. Vaginal stenosis will be evaluated separately in accordance with the study protocol.
Time frame: From the first brachytherapy procedure through 60 months after completion of treatment
Dose to Organs at Risk
Dose-volume parameters for organs at risk will be compared between treatment plans generated with the standard and individualized 3D-printed applicators. Evaluated organs include the bladder, rectum, sigmoid colon, and small bowel. Parameters include D2cc, D0.1cc, and maximum dose, expressed in gray.
Time frame: During brachytherapy treatment planning, before delivery of the planned brachytherapy dose
Local Tumor Control
Local control is defined as the absence of persistent or recurrent disease at the anatomical site of the tumor identified on baseline magnetic resonance imaging. Local control will be assessed by clinical and gynecological examinations and by magnetic resonance imaging. The number and percentage of participants with local control will be reported.
Time frame: From completion of treatment through 60 months
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