Weekly Volume and Dosimetric Changes During Chemoradiotherapy With Intensity-Modulated Radiation Therapy for Head and Neck Cancer: A Prospective Observational Study

Bhide, Shreerang A.; Davies, Mark; Burke, K.; McNair, Helen; Hansen, Vibeke; Barbáchano, Yolanda; El‐Hariry, Iman; Newbold, Kate; Harrington, Kevin; Nutting, Christopher M.

doi:10.1016/j.ijrobp.2009.04.005

Cited by 202 publications

(246 citation statements)

References 12 publications

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“…We show a significant averaged increase in

D_{mean}

in the parotid glands of 5.4% (3.8 Gy) at the 25th fraction, consistent with Lee et al, (15) who reported a difference between planned and received mean doses of less than 10% in 70% of studied patients. In our study, the parotid glands suffered a mean reduction of

1.4 % / td

, consistent with

1.5 % / td

in the study by Bhide et al, (12) although a little higher than Castadot et al and Lee et al 9 , 15 of

0.9 % ‐ 1.0 % / td

. No correlation was found between volume reduction and dose.…”

Section: Discussionsupporting

confidence: 91%

“…Several scheduled rescanning studies have evaluated these volumetric changes in both target volumes and normal tissues, 8 , 11 mostly on the parotid glands and their consequent effects on dose distribution 12 , 15 . The information obtained from these studies indicates that anatomical changes during the treatment can cause deviations between the planned and delivered dose, specifically reducing dosage to target volumes whilst increasing dosage to critical structures.…”

Section: Introductionmentioning

confidence: 99%

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Dose variations in tumor volumes and organs at risk during IMRT for head‐and‐neck cancer

Beltran

Ramos

Rovira

et al. 2012

J Applied Clin Med Phys

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Many head‐and‐neck cancer (HNC) patients treated with radiotherapy suffer significant anatomical changes due to tumor shrinkage or weight loss. The purpose of this study was to assess dose changes over target volumes and organs at risk during intensity‐modulated radiotherapy for HNC patients. Sixteen HNC IMRT patients, all requiring bilateral neck irradiation, were enrolled in the study. A CTplan was performed and the initial dose distribution was calculated. During the treatment, two subsequent CTs at the 15th (CT15) and 25th (CT25) fractions were acquired. The initial plan was calculated on the CT15 and CT25, and dose‐volume differences related to the CTplan were assessed. For target volumes, mean values of nearmaximun absorbed dose (normalD2%) increased at the 25th fraction, and doses covering 95% and 98% of volume decreased significantly at the 15th fraction. Contralateral and ipsilateral parotid gland mean doses increased by 6.1% (range: ‐5.4, 23.5%) and 4.7% (range: ‐9.1, 22.3%), respectively, at CT25. The normalD2% in the spinal cord increased by 1.8 Gy at CT15. Mean absorbed dose increases at CT15 and CT25 were observed in: the lips, 3.8% and 5.3%; the oral cavity, 3.5% and 2.5%; and lower middle neck structure, 1.9% and 1.6%. Anatomical changes during treatment of HNC patients affect dose distribution and induce a loss of dose coverage to target volumes and an overdosage to critical structures. Appropriate organs at risk have to be contoured and monitored in order to know if the initial plan remains suitable during the course of the treatment. Reported dosimetric data can help to identify patients who could benefit from adaptive radiotherapy.PACS numbers: 87.53.Kn, 87.55.Dk

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“…We show a significant averaged increase in

D_{mean}

1.4 % / td

, consistent with

1.5 % / td

in the study by Bhide et al, (12) although a little higher than Castadot et al and Lee et al 9 , 15 of

0.9 % ‐ 1.0 % / td

. No correlation was found between volume reduction and dose.…”

Section: Discussionsupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Dose variations in tumor volumes and organs at risk during IMRT for head‐and‐neck cancer

Beltran

Ramos

Rovira

et al. 2012

J Applied Clin Med Phys

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“…by computed tomography (CT), and are of concern during radiotherapy treatment 7, 8. The dosimetric consequences of such changes, namely the potential underdose of target volumes and overdose in organs at risk (OARs), have been quantified in detail for IMRT plans 9, 10. Treatment plan adaptation can be used to prevent severe dose degradation throughout the fractionated treatment course11 and is related with lower normal tissue complication probabilities 12.…”

Section: Introductionmentioning

confidence: 99%

Potential proton and photon dose degradation in advanced head and neck cancer patients by intratherapy changes

Stützer

Jakobi

Bandurska-Luque

et al. 2017

J Applied Clin Med Phys

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PurposeEvaluation of dose degradation by anatomic changes for head‐and‐neck cancer (HNC) intensity‐modulated proton therapy (IMPT) relative to intensity‐modulated photon therapy (IMRT) and identification of potential indicators for IMPT treatment plan adaptation.MethodsFor 31 advanced HNC datasets, IMPT and IMRT plans were recalculated on a computed tomography scan (CT) taken after about 4 weeks of therapy. Dose parameter changes were determined for the organs at risk (OARs) spinal cord, brain stem, parotid glands, brachial plexus, and mandible, for the clinical target volume (CTV) and the healthy tissue outside planning target volume (PTV). Correlation of dose degradation with target volume changes and quality of rigid CT matching was investigated.ResultsRecalculated IMPT dose distributions showed stronger degradation than the IMRT doses. OAR analysis revealed significant changes in parotid median dose (IMPT) and near maximum dose (D 1ml) of spinal cord (IMPT, IMRT) and mandible (IMPT). OAR dose parameters remained lower in IMPT cases. CTV coverage (V 95%) and overdose (V 107%) deteriorated for IMPT plans to (93.4 ± 5.4)% and (10.6 ± 12.5)%, while those for IMRT plans remained acceptable. Recalculated plans showed similarly decreased PTV conformity, but considerable hotspots, also outside the PTV, emerged in IMPT cases. Lower CT matching quality was significantly correlated with loss of PTV conformity (IMPT, IMRT), CTV homogeneity and coverage (IMPT). Target shrinkage correlated with increased dose in brachial plexus (IMRT, IMPT), hotspot generation outside the PTV (IMPT) and lower PTV conformity (IMRT).ConclusionsThe study underlines the necessity of precise positioning and monitoring of anatomy changes, especially in IMPT which might require adaptation more often. Since OAR doses remained typically below constraints, IMPT plan adaptation will be indicated by target dose degradations.

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“…As parotid glands produce approximately 60% of saliva and their anatomical changes during radiation therapy may have significant dosimetric implications, parotid protection-based ART has become a hot field of study in head and neck cancer IMRT [19,20]. In this study, we attempted to quantify the effect of anatomical changes on parotid dosimetry and to detect the factors that affect the actual dose that is delivered to the parotid gland.…”

Section: Discussionmentioning

confidence: 99%

Replanning Criteria and Timing Definition for Parotid Protection-Based Adaptive Radiation Therapy in Nasopharyngeal Carcinoma

Yao

et al. 2014

International Journal of Radiation Oncology*Biology*Physics

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Weekly Volume and Dosimetric Changes During Chemoradiotherapy With Intensity-Modulated Radiation Therapy for Head and Neck Cancer: A Prospective Observational Study

Cited by 202 publications

References 12 publications

Dose variations in tumor volumes and organs at risk during IMRT for head‐and‐neck cancer

Dose variations in tumor volumes and organs at risk during IMRT for head‐and‐neck cancer

Potential proton and photon dose degradation in advanced head and neck cancer patients by intratherapy changes

Replanning Criteria and Timing Definition for Parotid Protection-Based Adaptive Radiation Therapy in Nasopharyngeal Carcinoma

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