Point A vs. HR-CTV D90 in MRI-based cervical brachytherapy of small and large lesions

Harmon, Grant; Diak, A.M.; Shea, Steven M.; Yacoub, Joseph; Small, William; Harkenrider, Matthew M.

doi:10.1016/j.brachy.2016.08.010

Cited by 10 publications

(5 citation statements)

References 26 publications

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“…Harmon et al demonstrated in their study sufficient tumor coverage with lower doses to OARs in HR-CTV D 90 vs. Point A plans in the small lesion group. These improvements were not seen in the large lesion group, indicating a lesser dosimetric advantage of HR-CTV D90 compared to Point A planning when the cervical lesion is >25 cm 3 [14,15]. However, in our study, as expected coverage of the HR-CTV improves when the plan is optimised to a D90 of 100% of prescription dose rather than prescribing to the A points.…”

Section: Discussioncontrasting

confidence: 60%

Dynamics of high risk clinical target volume reduction during brachytherapy and impact on its coverage in patients with inoperable cervical cancer

Pobijakova¹,

Šćepanović²,

Paluga³

et al. 2018

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Cervical cancer is the third most common cancer in women worldwide. Standard of care for patients with node positive or locally advanced tumors >4 cm is definitive radiotherapy and concurrent chemotherapy. Brachytherapy is an integral part of definitive radiotherapy for cervical cancer. The aim of the study was to show a dynamics of High Risk Clinical Target Volume (HR-CTV) reduction during Brachytherapy (BT) as a part of definitive treatment (External Beam Radiotherapy /EBRT/ +/- Chemotherapy /ChT/) depending on the initial Gross Tumor Volume (GTV) and its impact on HR-CTV coverage in patients with inoperable cervical cancer. We analyzed the dosimetric data for BT of 54 patients who have had Three Dimensional Planning of BT (3D BT). The Gross Tumor Volume, HR-CTV and organs at risk (OARs) were contoured on the magnetic resonance imaging (MRI), subsequently on the co-registered MRI images with computed tomography (CT). Point A and ICRU 38 rectal and bladder points were defined on reconstructed CT images. Patients were categorized on the basis of whether the 100% isodose line of the point-A prescription dose encompassed the HR-CTV (1st group) or not (2nd group). The 30cc volume has been determined as a cut-off value, which represented the most acceptable value of intermediate size of volumes. The initial mean value of GTV was 42cc. After completion of EBRT/ChT, the mean GTV was 3.24cc what was 91% reduction rate in relation to the initial value. We followed the dynamics of HR-CTV reduction during BT and have noted its minimal reduction from 24.3cc (mean value) at the time of the first fraction to the 24.1cc before fourth fraction. The mean V100 was 98% and increased with decreasing of the volume size (p=0.0063, Fisher's exact test). D90 (mean value was 96.3 Gy10) has been correlated with V100 and also, it increased with decreasing of the volume size (p=0.0003). The mean D0.1cc and D2cc of rectum doses were 80 Gy3 and 65.6 Gy3, respectively. The mean ICRU rectal dose for all patients was 67.2 Gy3. The mean D0.1cc (99.5 Gy3), D2cc (79.5 Gy3) and ICRU (75.2 Gy3) of bladder doses were acceptable. Dynamics of HR-CTV reduction during BT was minimal, although, significant reduction of the GTV was achieved after EBRT/ChT. This study revealed that the dose prescription of 7 Gy × 4 fractions to point A was not sufficient indicator for dose coverage of the HR-CTV. However, dosimetric parameters as V100 and D90 were strong indicators for coverage of HR-CTV which was inversely related to the volume of the target and the extension of tumor. However, dosimetric parameters for rectum and bladder (D0.1cc, D2cc and ICRU) did not show dependence on the target volumes.

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Section: Discussioncontrasting

confidence: 60%

Dynamics of high risk clinical target volume reduction during brachytherapy and impact on its coverage in patients with inoperable cervical cancer

Pobijakova¹,

Šćepanović²,

Paluga³

et al. 2018

neo

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show abstract

“…Moreover, there were significantly higher doses with HR-CTV D 90 and D 100 (p < 0.05). However, there were no significant differences in HR-CTV D 90 dose parameters in the large lesion group (>25 cm 3 ), demonstrating that there was no dosimetric advantage of HR-CTV D 90 over Point A in this group [13].…”

Section: Discussionmentioning

confidence: 71%

“…Although point A plans met the suggested OAR dose limits, they reported that 15% and 17% of patients had genitourinary and gastrointestinal toxicities of grades 3-4, showing the dosimetric advantages of CT planning with the volumebased high-dose rate in providing significant HR-CTV while reducing OAR doses [18]. In another study by Harmon et al [13], twenty-eight fractions obtained from sixteen cervical cancer patients treated with MRI-based high-dose-rate brachytherapy. Lesions were divided into small (<25 cm 3 ) or large (>25 cm 3 ) volume.…”

Section: Discussionmentioning

confidence: 99%

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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

2021

EJGO

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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.

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“…Harmon et al (21) assessed the difference between 2D plans normalized to Point A and 3D target (HR-CTV) optimization under MRI guidance for 3-catheter IC treatment. The results showed that for patients with small tumor volume (HR-CTV !25 cm 3 ), the rectum, bladder, and sigmoid colon doses would be effectively lowered with the 3D target optimization method.…”

Section: Discussionmentioning

confidence: 99%

Dose distribution of brachytherapy for locally advanced (stage IIB) cervical cancer

et al. 2020

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Point A vs. HR-CTV D90 in MRI-based cervical brachytherapy of small and large lesions

Cited by 10 publications

References 26 publications

Dynamics of high risk clinical target volume reduction during brachytherapy and impact on its coverage in patients with inoperable cervical cancer

Dynamics of high risk clinical target volume reduction during brachytherapy and impact on its coverage in patients with inoperable cervical cancer

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

Dose distribution of brachytherapy for locally advanced (stage IIB) cervical cancer

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