Clinical Study of the Necessity of Replanning Before the 25th Fraction During the Course of Intensity-Modulated Radiotherapy for Patients With Nasopharyngeal Carcinoma

Wang, Wei; Yang, Haihua; Hu, Wei; Shan, Guihua; Ding, Wei; Yu, Chenchen; Wang, Biyun; Wang, Xufeng; Xu, Qiang

doi:10.1016/j.ijrobp.2009.08.036

Cited by 106 publications

(102 citation statements)

References 23 publications

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“…8,[10][11][12]14 Although several studies have found that adaptive replanning may potentially reduce dosage to the parotids, the appropriate means of selection remain elusive. 11,13,15,17,19 While our results did not identify any significant changes in parotid dose over the course of IMRT, this conclusion is limited by the heterogeneous patient population and the lack of cumulative dosage data.…”

Section: Discussioncontrasting

confidence: 72%

“…Overall, the medial shift of the parotid glands correlated with weight loss, confirming the findings of Barker et al 4 Other studies have attempted to correlate anatomic changes with dosimetric analysis and discussed the potential benefits of replanning in head and neck cancers. [7][8][9][10][11][12][13]15,17,19 As the parotid glands shift medially during IMRT, they may be exposed to higher than expected levels of radiation and consequently an increased probability of xerostomia. 8,[10][11][12]14 Although several studies have found that adaptive replanning may potentially reduce dosage to the parotids, the appropriate means of selection remain elusive.…”

Section: Discussionmentioning

confidence: 99%

“…[4][5][6][7][8][9][10] Interfractional anatomical changes, in turn, can substantially alter dose deposition, suggesting a benefit to adaptive replanning. [7][8][9][10][11][12][13][14][15][16][17][18][19] However, adaptive replanning remains to be widely adopted owing to its time-intensive nature and an unclear threshold of anatomical changes required for its posited benefit. 10,11,16,20 The aforementioned studies of anatomical alteration during IMRT relied on CT imaging, which might not provide optimal soft-tissue contrast/ resolution, leading to possible interobserver variability.…”

Section: Introductionmentioning

confidence: 99%

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Anatomic and dosimetric changes in patients with head and neck cancer treated with an integrated MRI-tri-⁶⁰Co teletherapy device

Raghavan

Kishan

Cao

et al. 2016

BJR

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Objective: Prior studies have relied on CT to assess alterations in anatomy among patients undergoing radiation for head and neck cancer. We sought to determine the feasibility of using MRI-based image-guided radiotherapy to quantify these changes and to ascertain their potential dosimetric implications. Methods: 6 patients with head and neck cancer were treated with intensity-modulated radiotherapy (IMRT) on a novel tri- 60Co teletherapy system equipped with a 0.35-T MRI (VR, ViewRay Incorporated, Oakwood Village, OH) to 66-70 Gy in 33 fractions (fx). Pre-treatment MRIs on Fx 1, 5, 10, 15, 20, 25, 30 and 33 were imported into a contouring interface, where the primary gross tumour volume (GTV) and parotid glands were delineated. The centre of mass (COM) shifts for these structures were assessed relative to Day 1. Dosimetric data were co-registered with the MRIs, and doses to the GTV and parotid glands were assessed.Results: Primary GTVs decreased significantly over the course of IMRT (median % volume loss, 38.7%; range, 29.5-72.0%; p , 0.05) at a median rate of 1.2%/ fx (range, 0.92-2.2%/fx). Both the ipsilateral and contralateral parotid glands experienced significant volume loss (p , 0.05, for all) and shifted medially during IMRT. Weight loss correlated significantly with parotid gland volume loss and medial COM shift (p , 0.05). Conclusion: Integrated on-board MRI can be used to accurately contour and analyze primary GTVs and parotid glands over the course of IMRT. COM shifts and significant volume reductions were observed, confirming the results of prior CT-based exercises. Advances in knowledge: The superior resolution of onboard MRI may facilitate online adaptive replanning in the future.

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Section: Discussioncontrasting

confidence: 72%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Anatomic and dosimetric changes in patients with head and neck cancer treated with an integrated MRI-tri-⁶⁰Co teletherapy device

Raghavan

Kishan

Cao

et al. 2016

BJR

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“…Adaptive RT based on replanning during treatment is a common strategy to minimize the effect of anatomical changes over dose distribution, 16 , 17 although identifying which patients in particular could best benefit from replanning is, as yet, undetermined. Ahn et al (18) indicated the need for an accurate determination of anatomical changes and their consequent dosimetric parameters as a prime factor in the determination of any subsequent replanning.…”

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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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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“…Accordingly, they concluded that in the case of nasopharyngeal carcinoma radiotherapy, replanning based on the changes in tumor size may better protect at-risk organs such as the parotid gland, spinal cord and brain stem (54). Wang et al reported that in 28 cases of replanning of nasopharyngeal carcinoma IMRT, the dose in high-risk targets increased by 4.9-10.8%, the maximum dose in the spinal cord decreased by 5-9.23 Gy and the average dose in the parotid gland decreased by 4.23-10.03 Gy with replanning following 25 fractionations of radiotherapy followed by CT scan (55).…”

Section: How Do Radiation-induced Responses Modify Radiotherapy?mentioning

confidence: 99%

Strategies to optimize radiotherapy based on biological responses of tumor and normal tissue

Wang

Lang

2012

Experimental and Therapeutic Medicine

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Abstract. Rapid developments in radiation oncology are currently taking place. Radiation-induced responses are being increasingly used for radiotherapy modification based on advancements in radiobiology. In the process of radiation treatment, radiobiological responses of tumor and normal tissue in patients are monitored non-invasively by a variety of techniques including imaging, biological methods and biochemical assays. Information collected using these methods and data on responses are further incorporated into radiotherapy optimization approaches, which not only include the optimization of radiation treatment planning, such as dose distributions in targets and treatment delivery, but also include radiation sensitivity modification and gene radiotherapy of the tumor and normal tissue. Hence, the highest tumor control rate is obtained with the utmost protection being afforded to normal tissue under this treatment modality.

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Clinical Study of the Necessity of Replanning Before the 25th Fraction During the Course of Intensity-Modulated Radiotherapy for Patients With Nasopharyngeal Carcinoma

Cited by 106 publications

References 23 publications

Anatomic and dosimetric changes in patients with head and neck cancer treated with an integrated MRI-tri-⁶⁰Co teletherapy device

Anatomic and dosimetric changes in patients with head and neck cancer treated with an integrated MRI-tri-⁶⁰Co teletherapy device

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

Strategies to optimize radiotherapy based on biological responses of tumor and normal tissue

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Clinical Study of the Necessity of Replanning Before the 25th Fraction During the Course of Intensity-Modulated Radiotherapy for Patients With Nasopharyngeal Carcinoma

Cited by 106 publications

References 23 publications

Anatomic and dosimetric changes in patients with head and neck cancer treated with an integrated MRI-tri-60Co teletherapy device

Anatomic and dosimetric changes in patients with head and neck cancer treated with an integrated MRI-tri-60Co teletherapy device

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

Strategies to optimize radiotherapy based on biological responses of tumor and normal tissue

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Product

Resources

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Anatomic and dosimetric changes in patients with head and neck cancer treated with an integrated MRI-tri-⁶⁰Co teletherapy device

Anatomic and dosimetric changes in patients with head and neck cancer treated with an integrated MRI-tri-⁶⁰Co teletherapy device