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      Impact of different dose prescription schedules on EQD2 in high-dose-rate intracavitary brachytherapy of carcinoma cervix.

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          Abstract

          To observe the effect of different high-dose-rate (HDR) intracavitary brachytherapy dose schedules on equieffective dose in 2 Gy per fraction (EQD2).

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          Most cited references 17

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          Clinical outcome of protocol based image (MRI) guided adaptive brachytherapy combined with 3D conformal radiotherapy with or without chemotherapy in patients with locally advanced cervical cancer

          Background To analyse the overall clinical outcome and benefits by applying protocol based image guided adaptive brachytherapy combined with 3D conformal external beam radiotherapy (EBRT) ± chemotherapy (ChT). Methods Treatment schedule was EBRT with 45–50.4 Gy ± concomitant cisplatin chemotherapy plus 4 × 7 Gy High Dose Rate (HDR) brachytherapy. Patients were treated in the “protocol period” (2001–2008) with the prospective application of the High Risk CTV concept (D90) and dose volume constraints for organs at risk including biological modelling. Dose volume adaptation was performed with the aim of dose escalation in large tumours (prescribed D90 > 85 Gy), often with inserting additional interstitial needles. Dose volume constraints (D2cc) were 70–75 Gy for rectum and sigmoid and 90 Gy for bladder. Late morbidity was prospectively scored, using LENT/SOMA Score. Disease outcome and treatment related late morbidity were evaluated and compared using actuarial analysis. Findings One hundred and fifty-six consecutive patients (median age 58 years) with cervix cancer FIGO stages IB–IVA were treated with definitive radiotherapy in curative intent. Histology was squamous cell cancer in 134 patients (86%), tumour size was >5 cm in 103 patients (66%), lymph node involvement in 75 patients (48%). Median follow-up was 42 months for all patients. Interstitial techniques were used in addition to intracavitary brachytherapy in 69/156 (44%) patients. Total prescribed mean dose (D90) was 93 ± 13 Gy, D2cc 86 ± 17 Gy for bladder, 65 ± 9 Gy for rectum and 64 ± 9 Gy for sigmoid. Complete remission was achieved in 151/156 patients (97%). Overall local control at 3 years was 95%; 98% for tumours 2–5 cm, and 92% for tumours >5 cm (p = 0.04), 100% for IB, 96% for IIB, 86% for IIIB. Cancer specific survival at 3 years was overall 74%, 83% for tumours 2–5 cm, 70% for tumours >5 cm, 83% for IB, 84% for IIB, 52% for IIIB. Overall survival at 3 years was in total 68%, 72% for tumours 2–5 cm, 65% for tumours >5 cm, 74% for IB, 78% for IIB, 45% for IIIB. In regard to late morbidity in total 188 grade 1 + 2 and 11 grade 3 + 4 late events were observed in 143 patients. G1 + 2/G3 + 4 events for bladder were n = 32/3, for rectum n = 14/5, for bowel (including sigmoid) n = 3/0, for vagina n = 128/2, respectively. Interpretation 3D conformal radiotherapy ± chemotherapy plus image (MRI) guided adaptive intracavitary brachytherapy including needle insertion in advanced disease results in local control rates of 95–100% at 3 years in limited/favourable (IB/IIB) and 85–90% in large/poor response (IIB/III/IV) cervix cancer patients associated with a moderate rate of treatment related morbidity. Compared to the historical Vienna series there is relative reduction in pelvic recurrence by 65–70% and reduction in major morbidity. The local control improvement seems to have impact on CSS and OS. Prospective clinical multi-centre studies are mandatory to evaluate these challenging mono-institutional findings.
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            Computed tomography versus magnetic resonance imaging-based contouring in cervical cancer brachytherapy: results of a prospective trial and preliminary guidelines for standardized contours.

            To compare the contours and dose-volume histograms (DVH) of the tumor and organs at risk (OAR) with computed tomography (CT) vs. magnetic resonance imaging (MRI) in cervical cancer brachytherapy. Ten patients underwent both MRI and CT after applicator insertion. The dose received by at least 90% of the volume (D(90)), the minimal target dose (D(100)), the volume treated to the prescription dose or greater for tumor for the high-risk (HR) and intermediate-risk (IR) clinical target volume (CTV) and the dose to 0.1 cm3, 1 cm3, and 2 cm3 for the OARs were evaluated. A standardized approach to contouring on CT (CT(Std)) was developed, implemented (HR- and IR-CTV(CTStd)), and compared with the MRI contours. Tumor height, thickness, and total volume measurements, as determined by either CT or CT(Std) were not significantly different compared with the MRI volumes. In contrast, the width measurements differed in HR-CTV(CTStd) (p = 0.05) and IR-CTV(CTStd) (p = 0.01). For the HR-CTV(CTStd), this resulted in statistically significant differences in the volume treated to the prescription dose or greater (MRI, 96% vs. CT(Std), 86%, p = 0.01), D(100) (MRI, 5.4 vs. CT(Std), 3.4, p <0.01), and D(90) (MRI, 8.7 vs. CT(Std), 6.7, p <0.01). Correspondingly, the IR-CTV DVH values on MRI vs. CT(Std), differed in the D(100) (MRI, 3.0 vs. CT(Std), 2.2, p = 0.01) and D(90) (MRI, 5.6 vs. CT(Std), 4.6, p = 0.02). The MRI and CT DVH values of the dose to 0.1 cm3, 1 cm3, and 2 cm3 for the OARs were similar. Computed tomography-based or MRI-based scans at brachytherapy are adequate for OAR DVH analysis. However, CT tumor contours can significantly overestimate the tumor width, resulting in significant differences in the D(90), D(100), and volume treated to the prescription dose or greater for the HR-CTV compared with that using MRI. MRI remains the standard for CTV definition.
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              American Brachytherapy Society consensus guidelines for locally advanced carcinoma of the cervix. Part II: high-dose-rate brachytherapy.

              This report presents an update to the American Brachytherapy Society (ABS) high-dose-rate (HDR) brachytherapy guidelines for locally advanced cervical cancer. Members of the ABS with expertise in cervical cancer formulated updated guidelines for HDR brachytherapy using tandem and ring, ovoids, cylinder, or interstitial applicators for locally advanced cervical cancer. These guidelines were written based on medical evidence in the literature and input of clinical experts in gynecologic brachytherapy. The ABS affirms the essential curative role of tandem-based brachytherapy in the management of locally advanced cervical cancer. Proper applicator selection, insertion, and imaging are fundamental aspects of the procedure. Three-dimensional imaging with magnetic resonance or computed tomography or radiographic imaging may be used for treatment planning. Dosimetry must be performed after each insertion before treatment delivery. Applicator placement, dose specification, and dose fractionation must be documented, quality assurance measures must be performed, and followup information must be obtained. A variety of dose/fractionation schedules and methods for integrating brachytherapy with external-beam radiation exist. The recommended tumor dose in 2-Gray (Gy) per fraction radiobiologic equivalence (normalized therapy dose) is 80-90Gy, depending on tumor size at the time of brachytherapy. Dose limits for normal tissues are discussed. These guidelines update those of 2000 and provide a comprehensive description of HDR cervical cancer brachytherapy in 2011. Copyright © 2012 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.
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                Author and article information

                Journal
                J Contemp Brachytherapy
                Journal of contemporary brachytherapy
                Termedia Sp. z.o.o.
                1689-832X
                2081-2841
                Apr 2019
                : 11
                : 2
                Affiliations
                [1 ] Ramaiah Medical College Bengaluru, India.
                Article
                36439
                10.5114/jcb.2019.84586
                6536140

                cervical cancer, EQD2, brachytherapy

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