MRI reduces variation of contouring for boost clinical target volume in breast cancer patients without surgical clips in the tumour bed

Al-Hammadi, Noora; Caparrotti, Palmira; Divakar, S.; Riyas, M.; Chandramouli, S.; Hammoud, R.; Hayes, Jillian; Garry, Maeve Mc; Paloor, S.; Petrič, Primož

doi:10.1515/raon-2017-0014

Cited by 20 publications

(20 citation statements)

References 54 publications

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“…Two previous studies also revealed a positive association between the CVS and CI gen [15,18], but neither reported a correlation coefficient or P values as we have done in the current study. Moreover, MR was reported to improve CT-assessed CVS in 11 cases (92%) in another study [15], while the corresponding number in our study was 15 cases (75%). These results are on par with those reported previously, which demonstrated that lumpectomy cavities were more visible in images of four different MR sequence images than in CT images [16].…”

Section: Discussioncontrasting

confidence: 97%

“…Similar to our findings, a study comparing CT and MR images from 33 patients delineated by 11 observers, reported a negative correlation between the CVS and IOV parameters [26]. Two previous studies also revealed a positive association between the CVS and CI gen [15,18], but neither reported a correlation coefficient or P values as we have done in the current study. Moreover, MR was reported to improve CT-assessed CVS in 11 cases (92%) in another study [15], while the corresponding number in our study was 15 cases (75%).…”

Section: Discussionsupporting

confidence: 88%

“…Recently, researchers have explored the role and feasibility of MR in breast radiotherapy [13,14], while an increasing number of studies have focused on comparing MR with CT simulation in defining and delineating the tumor bed for radiotherapy after breastconserving surgery. Some of these groups believed that MR can provide clearer visualization of breast lumpectomy cavity and improve accuracy and consistency in delineating tumor bed [15][16][17]. However, others found that there were no differences in target volumes or the IOV between two modalities [8,18,19].…”

Section: Introductionmentioning

confidence: 99%

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The impact of different simulation modalities on target volume delineation in breast-conserving radiotherapy

Jin

Liu

et al. 2020

Preprint

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Background In the management of breast-conserving radiotherapy, computed tomography (CT) simulation is now commonly used to identify tumor bed while has difficult ies defining precisely. We aimed to evaluate the impact of magnetic resonance (MR) and CT simulation on defining the postoperative tumor bed for breast-conserving radiotherapy in patients without the aid of surgical clips. Methods From August 2018 to March 2019, twenty patients with T 1 - 2 N 0 M 0 breast cancer at our situation were enrolled. All the patients underwent breast-conserving surgery without implantation of surgical clips and were prepared to receive radiotherapy. CT and MR images were acquired on the same day for each patient. Three radiation oncologists independently assigned cavity visualization score (CVS) and delineated the tumor bed based on first the CT then the MR images with a 14-day interval for each patient. Interobserver variability was assessed by volumes, generalized conformity index (CI gen ) and the distance between the centers of mass (dCOM). Differences in mean values for parameters were tested by paired t -test or one-way analysis of variance, as appropriate. Results The median age of the enrolled patients was 48 years old. First, the mean volumes of tumor bed derived from MR were 22%, 27% and 21% smaller than those based on CT images for each observer. Second, the mean CI gen was significantly superior, and dCOM was smaller for MR than for CT images (CI gen : 0.59 vs 0.52, P = 0.008; dCOM: 1.30 cm vs 1.39 cm, P = 0.095). Third, the mean CVS was 3.23±1.34 and 2.43±0.92 for MR and CT images, respectively ( P = 0.035). In the subgroup with a CT-based CVS≥3, the mean dCOM obtained from CT was larger than that from the MR images (1.35 cm vs 1.19 cm, P = 0.048). Last, there was a positive association between the CVS and CI gen for both modalities (CT: r = 0.699, P = 0.001; MR: r = 0.895, P ＜ 0.001). Conclusion Compared to CT, MR can improve the visualization of changes in the postoperative tumor bed. In addition, MR can yield a more precise definition of the tumor bed and improve the consistency of tumor bed contouring in patients without surgical clips.

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Section: Discussioncontrasting

confidence: 97%

Section: Discussionsupporting

confidence: 88%

Section: Introductionmentioning

confidence: 99%

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The impact of different simulation modalities on target volume delineation in breast-conserving radiotherapy

Jin

Liu

et al. 2020

Preprint

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“…Third, in three separate studies, MRI did not lead to a reduction in interobserver variation (20,24,50). However, in a more recent larger study, a significant reduction in interobserver variation was reported for delineation on MRI in patients without surgical clips (51). Therefore, the added value of using MRI for contouring in the adjuvant setting seems likely to be limited to those patients in whom tumour bed clips have not been placed.…”

Section: Contouringmentioning

confidence: 89%

Optimizing MR-Guided Radiotherapy for Breast Cancer Patients

et al. 2020

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Current research in radiotherapy (RT) for breast cancer is evaluating neoadjuvant as opposed to adjuvant partial breast irradiation (PBI) with the aim of reducing the volume of breast tissue irradiated and therefore the risk of late treatment-related toxicity. The development of magnetic resonance (MR)-guided RT, including dedicated MR-guided RT systems [hybrid machines combining an MR scanner with a linear accelerator (MR-linac) or 60 Co sources], could potentially reduce the irradiated volume even further by improving tumour visibility before and during each RT treatment. In this position paper, we discuss MR guidance in relation to each step of the breast RT planning and treatment pathway, focusing on the application of MR-guided RT to neoadjuvant PBI.

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“…However, this study had low numbers of patients and oncologists. 26 Karki et al found no difference in interobserver variation between MRI and PET-CT for non-small-cell lung carcinoma radiotherapy planning, when using a bidirectional local distance measure to compare individual clinicians’ contours with a median contour. 27 Barkati et al observed a higher DSC using CT v s MRI for prostate radiotherapy planning, indicating increased interobserver variation with MRI.…”

Section: Discussionmentioning

confidence: 99%

Does magnetic resonance imaging improve soft tissue sarcoma contouring for radiotherapy?

et al. 2019

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Objective: Soft tissue sarcomas (STS) are a rare, heterogeneous tumour group. Radiotherapy improves local control. CT is used to plan radiotherapy, but has poor soft tissue definition. MRI has superior soft tissue definition. Contour variation amongst oncologists is an important factor in treatment failure. This study is the first to directly compare STS tumour contouring using CT vs MRI. Methods: Planning CT and T2 weighted MR images of eight patients with STS were distributed to four oncologists. Gross tumour volume was contoured on both imaging modalities using in-house software. Images were recontoured 6 weeks later. The mean distance to agreement (DTA), standard deviation of the DTA, dice similarity coefficient (DSC) and contour volume were calculated for each oncologist and compared to a median contour volume. Results for CT and MRI were compared using a pairwise Student's t-test. Results: When comparing MRI to CT, tumour volumes were significantly smaller, with a difference of 21.4 cm3 across all patients (p = 0.008). There was not a statistically significant difference in the mean distance to agreement or dice similarity coefficient, but the standard deviation of the DTA showed a statistically significant improvement ( p = 0.04). For intraobserver variation, there was no statistically significant improvement using MRI vs CT. Conclusion: Oncologists contour smaller tumour volumes using MRI, with reduced interobserver variation. Improving the reliability and consistency of contouring is needed for improved quality assurance. Advances in knowledge: With further experience, the use of MRI in STS radiotherapy planning may reduce variation between oncologists and contribute to improved local control and reduced treatment toxicities.

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MRI reduces variation of contouring for boost clinical target volume in breast cancer patients without surgical clips in the tumour bed

Cited by 20 publications

References 54 publications

The impact of different simulation modalities on target volume delineation in breast-conserving radiotherapy

The impact of different simulation modalities on target volume delineation in breast-conserving radiotherapy

Optimizing MR-Guided Radiotherapy for Breast Cancer Patients

Does magnetic resonance imaging improve soft tissue sarcoma contouring for radiotherapy?

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