Dosimetric evaluation of vaginal cuff brachytherapy planning in cervical and endometrial cancer patients

Katarzyna Sikorska; Agnieszka Zolciak-Siwinska; Adam Kowalczyk; Michał Bijok; Wojciech Michalski; Ewelina Gruszczynska

doi:10.5114/jcb.2020.96865

eISSN: 2081-2841
ISSN: 1689-832X

Journal of Contemporary Brachytherapy

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3/2020
vol. 12

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abstract:

Original paper

Dosimetric evaluation of vaginal cuff brachytherapy planning in cervical and endometrial cancer patients

Katarzyna Sikorska

¹

,

Agnieszka Zolciak-Siwinska

²

,

Adam Kowalczyk

¹

,

Michał Bijok

¹

,

Wojciech Michalski

³

,

Ewelina Gruszczynska

¹

Department of Medical Physics, Maria Sklodowska-Curie National Research Institute of Oncology, Warsaw, Poland
Department of Gynecological Oncology, Maria Sklodowska-Curie National Research Institute of Oncology, Warsaw, Poland
Department of Clinical Trials and Biostatistics, Maria Sklodowska-Curie National Research Institute of Oncology, Warsaw, Poland

J Contemp Brachytherapy 2020; 12, 3: 248–251

DOI: https://doi.org/10.5114/jcb.2020.96865

Online publish date: 2020/06/30

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Introduction
The aim of the study was to perform a prospective analysis of dosimetric consequences of rectal enema administration before vaginal cuff brachytherapy (VCB), the dose distribution in organs at risk (OARs), and the presence of air gaps (AGs) in patients with cervical or endometrial cancer.

Material and methods
In total, 75 patients treated in 2019 were randomly divided into two groups including 38 patients with and 37 without an enema before VCB. All patients received post-operative high-dose-rate (HDR). Single-channel vaginal cylinders with active length of 2.75 cm were used. Prescription dose was 7 Gy at 5 mm depth from the applicator surface in all directions. Treatment plans were based on computed tomography (CT).

Results
Enema performed before cylinder insertion had no effect on rectosigmoid Dmax or D2cm3. Rectosigmoid median V100 was 0.5 cm3 (range, 0-2.7 cm3). V100 ≥ 1 cm3 in 22 and ≥ 2 cm3 in 6 patients, with Dmax up to 19.7 Gy (282%) were observed. No effect of bladder volume in the range of 27-256 cm3 on Dmax or D2cm3 was found. The median bladder V100 was 0.1 cm3 (range, 0-1.4 cm3). There were 62 (83%) patients with AGs, with 24% at the top of the vagina and 75% on the remaining length of the vagina. Most of the AGs were small (≤ 3 mm), but in 5 (8%) cases, they were bigger than 5 mm.

Conclusions
VCB planning with the use of CT is essential. CT can facilitate the selection of optimal cylinder size to reduce the occurrence of large AGs. A few percent of plans require correction of dose distribution because of hot spots in OARs and the presence of AGs. Enema before cylinder insertion does not influence rectosigmoid Dmax and D2cm3. The analysis revealed no bladder volume effect on bladder doses Dmax and D2cm3.

keywords:

Dosimetric evaluation of vaginal cuff brachytherapy planning in cervical and endometrial cancer patients

Katarzyna Sikorska 1 , Agnieszka Zolciak-Siwinska 2 , Adam Kowalczyk 1 , Michał Bijok 1 , Wojciech Michalski 3 , Ewelina Gruszczynska 1

HDR, CT, VCB, cervical or endometrial cancer, enema, AGs

Katarzyna Sikorska

¹

,

Agnieszka Zolciak-Siwinska

²

,

Adam Kowalczyk

¹

,

Michał Bijok

¹

,

Wojciech Michalski

³

,

Ewelina Gruszczynska

¹