IMR Press / EJGO / Volume 42 / Issue 5 / DOI: 10.31083/j.ejgo4205141
Open Access Original Research
Comparison of point a based plans with clinical target volume-based three-dimensional plans using dose–volume parameters in small lesion of cervical cancer brachyterapy
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1 Department of Radiation Oncology, Health Sciences University Bakirkoy Dr. Sadi Konuk Training and Research Hospital, 34147 Istanbul, Turkey
2 Department of Radiation Oncology, Health Sciences University Sisli Hamidiye Etfal Training and Research Hospital, 34371 Istanbul, Turkey
Eur. J. Gynaecol. Oncol. 2021 , 42(5), 936–942; https://doi.org/10.31083/j.ejgo4205141
Submitted: 21 July 2021 | Revised: 4 September 2021 | Accepted: 17 September 2021 | Published: 15 October 2021
Abstract

Objective: Intracavitary brachytherapy (ICBT) is the most critical part of cervical cancer treatment which contains a combination of external and intracavitary radiotherapy. We aimed to compare two different plans normalized to point A and the high-risk clinical target volume (HR-CTV) in terms of the target volume and doses for organs at risk (OARs). Methods: Twenty-eight patients with small-residue cervical tumor volume who received CT-based brachytherapy treatment with uterus tandem and double ovoid applicators were included in the study. 3D-ICBT treatment plans normalized to HR-CTV and point A were applied separately to five fractions. We made a total of 280 plans for the two treatment techniques. The patients were given a dose of 5.5 Gy per fraction for a total of 27.5 Gy in 5 fractions. The doses to OAR (rectum, sigmoid, and bladder) and HR-CTV were compared between HR-CTV and point A - based plans. Results: In the brachytherapy treatment planning, the mean doses of HR-CTV D90 and IR-CTV D100 were significantly lower in each fraction and in the total doses when normalized to HR-CTV than when normalized to point A (p < 0.001). D1cc, D2cc, and Dmax values of OAR doses obtained from the brachytherapy treatment planning were significantly lower in each fraction and in the total doses when normalized to HR-CTV than when normalized to point A (p < 0.001). Conclusion: Our findings revealed that, particularly in small-volume HR-CTV after EBRT, plans normalized to HR-CTV can reduce overdose in the target tissue and avoid unnecessary OAR irradiation compared to the plans normalized to point A.

Keywords
Intracavitary brachytherapy
Cervical cancer
Point A
HR-CTV
Tumor size
Three-dimensional treatment plan
CT scan
Figures
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