Factors influencing bowel sparing in intensity modulated whole pelvic radiotherapy for gynaecological malignancies

Georg, Petra; Georg, Dietmar; Hillbrand, Martin; Kirisits, Christian; Pötter, Richard

doi:10.1016/j.radonc.2006.04.014

Cited by 81 publications

(50 citation statements)

References 22 publications

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“…The IMRT technique has the potential benefit over conventional CRT of improving target coverage, reducing the volume of the organs at risk (OARs) that receive irradiation, and reducing the toxicity to normal tissue 8. Dosimetric studies have shown a significant reduction in the dose to small bowel with IMRT when compared to conventional CRT.…”

Section: Introductionmentioning

confidence: 99%

Dosimetric benefits of intensity‐modulated radiotherapy and volumetric‐modulated arc therapy in the treatment of postoperative cervical cancer patients

Deng

Han

Chen³

et al. 2016

J Applied Clin Med Phys

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As the advantage of using complex volumetric‐modulated arc therapy (VMAT) in the treatment of gynecologic cancer has not yet been fully determined, the purpose of this study was to investigate the dosimetric advantages of VMAT by comparing directly with whole pelvic conformal radiotherapy (CRT) and intensity‐modulated radiotherapy (IMRT) in the treatment of 15 postoperative cervical cancer patients. Four‐field CRT, seven‐field IMRT, and two‐arc VMAT plans were generated for each patient with identical objective functions to achieve clinically acceptable dose distribution. Target coverage and OAR sparing differences were investigated through dose‐volume histogram (DVH) analysis. Nondosimtric differences between IMRT and VMAT were also compared. Target coverage presented by V95% were 88.9% ± 3.8%, 99.9% ± 0.07%, and 99.9% ± 0.1% for CRT, IMRT, and VMAT, respectively. Significant differences on conformal index (CI) and conformal number (CN) were observed with CIs of 0.37 ± 0.07, 0.55 ± 0.04, 0.61 ± 0.04, and CNs of 0.33 ± 0.06, 0.55 ± 0.04, 0.60 ± 0.04 for CRT, IMRT, and VMAT, respectively. IMRT and VMAT decreased the dose to bladder and rectum significantly compared with CRT. No significant differences on the Dmean, V45, and V30 of small bowel were observed among CRT, IMRT, and VMAT. However, VMAT (10.4 ± 4.8 vs. 19.8 ± 11.0, P = 0.004) and IMRT (12.3 ± 5.0 vs. 19.8 ± 11.0, P = 0.02) decreased V40, increased the Dmax of small bowel and the irradiation dose to femoral heads compared with CRT. VMAT irradiated less dose to bladder, rectum, small bowel and larger volume of health tissue with a lower dose (V5 and V10) compared with IMRT, although the differences were not statistical significant. In conclusion, VMAT and IMRT showed significant dosimetric advantages both on target coverage and OAR sparing compared with CRT in the treatment of postoperative cervical cancer. However, no significant difference between IMRT and VMAT was observed except for slightly better dose conformity, slightly less MU, and significant shorter delivery time achieved for VMAT.

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Section: Introductionmentioning

confidence: 99%

Dosimetric benefits of intensity‐modulated radiotherapy and volumetric‐modulated arc therapy in the treatment of postoperative cervical cancer patients

Deng

Han

Chen³

et al. 2016

J Applied Clin Med Phys

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“…19,20 However, the generation of ITV necessitates careful identification of targets on MVCT/KVCT scans. For the conduct of the present study, we hypothesized that the displacement characteristics of central recurrences may be different than that of uterus [21][22][23] and post-surgical vaginal remnant [24][25][26][27] and need prospective investigation. The methodology in the present study relied on evaluating COM displacement of recurrent tumour on daily MVCT images.…”

Section: Discussionmentioning

confidence: 99%

Internal target volume for post-hysterectomy vaginal recurrences of cervical cancers during image-guided radiotherapy

Upasani

Chopra

Mahantshetty

et al. 2015

BJR

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Objective: The outcome of post-surgical recurrences of cervical cancer may be improved through radiation dose escalation, which hinges on accurate identification and treatment of the target. The present study quantifies target motion during course of image-guided radiotherapy (IGRT) for vault cancers. Methods: All patients underwent planning CT simulation after bladder-filling protocol. A daily pre-treatment megavoltage CT was performed. All translations and rotations were recorded. Post-registration displacement of gross tumour volume (GTV) and centre of mass (COM) of GTV was independently recorded by two observers for fractions one to seven. Day 1 image sets served as reference images against which the displacements of COM were measured. We calculated the displacements of common volume (CV) and encompassing volume (EV) of GTV for both the observers. Results: A total of 90 image data sets of 15 patients were available for evaluation. Individual patient GTV and average GTV by both the observers were comparable. The average shifts for EV were 2.4 mm [standard deviation (SD) 6 1.2] in the mediolateral, 4.2 mm (SD 6 2.8) in the anteroposterior and 4.0 mm (SD 62.1) in superoinferior directions. Similarly, the average shifts for CV were 1.9 mm (SD 60.6) in the mediolateral, 3.7 mm (SD 62.7) in the anteroposterior and 4.4 mm (SD 62.7) in superoinferior directions. Using Stroom's/van Herk's formula, the minimum recommended margins would be 4.5/5.2, 8.2/9.4 and 7.3/8.3 mm, respectively, for lateral, anteroposterior and superoinferior directions. Conclusion: Differential directional internal margin is recommended in patients undergoing IGRT for postsurgical recurrence of cervical cancers. Advances in knowledge: Internal organ motion of vault cancers can be accounted for by a directional margin to the gross tumour.

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“…[12][13][14][15][16][17][18] However, smallbowel sparing achieved with the use of IMRT is markedly reduced by relatively small expansions of the target volume. Therefore, accurate target delineation, highly reproducible patient immobilization and a clear understanding of internalorgan motion are needed to achieve optimal advantage in the use of IMRT over conventional methods of post-hysterectomy pelvic radiation therapy.…”

Section: Discussionmentioning

confidence: 99%

Vaginal displacement during course of adjuvant radiation for cervical cancer: results from a prospective IG-IMRT study

Chopra

Patidar²,

Dora³

et al. 2014

BJR

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Objective: To compare internal target volume (ITV) generated using population-based displacements (ITV_study) with empty and full bladder scan fusion (ITV_EBFB) for organ-at-risk (OAR) doses during adjuvant intensitymodulated radiation therapy (IMRT) for cervical cancer. Methods: From January 2011 to October 2012, patients undergoing IMRT were included. CT simulation was carried out after inserting vault markers. Planning target volume (PTV)_EBFB received 50 Gy per 25 fractions. Pre-treatment megavoltage CT (MVCT) was performed. MVCTs were registered using bony landmarks with Day 1 MVCT. Displacement of the centre of mass of markers was measured along each axis. Directional ITV was calculated using mean 6 2 standard deviations (SDs) (ITV_study). Replanning was performed using PTV study, and OAR doses were compared with PTV_EBFB using Wilcoxon test.Results: A total of 348/386 data sets were evaluable for 16 patients. The median vaginal displacement was 1.2 mm (SD, 1.3 mm), 4.0 mm (SD, 3.5 mm) and 2.8 mm (SD, 3.3

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Factors influencing bowel sparing in intensity modulated whole pelvic radiotherapy for gynaecological malignancies

Cited by 81 publications

References 22 publications

Dosimetric benefits of intensity‐modulated radiotherapy and volumetric‐modulated arc therapy in the treatment of postoperative cervical cancer patients

Dosimetric benefits of intensity‐modulated radiotherapy and volumetric‐modulated arc therapy in the treatment of postoperative cervical cancer patients

Internal target volume for post-hysterectomy vaginal recurrences of cervical cancers during image-guided radiotherapy

Vaginal displacement during course of adjuvant radiation for cervical cancer: results from a prospective IG-IMRT study

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