The impact of restricted length of treatment field and anthropometric factors on selection of head and neck cancer patients for treatment on the MR-Linac.
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Date
2020-07-01Author
Ng-Cheng-Hin, B
Nutting, C
Newbold, K
Bhide, S
McQuaid, D
Dunlop, A
Harrington, K
Wong, KH
Type
Journal Article
Metadata
Show full item recordAbstract
OBJECTIVE: This study investigates the impact of a restricted craniocaudal (CC) field length of <20 cm on the selection of head and neck cancer (HNC) patients who can be treated on the MR-Linac using a single isocentre technique. We also assess the effects of anthropometric factors and the neck position on the CC field length. METHODS: 110 HNC patients who underwent radical primary or adjuvant radiotherapy were retrospectively analysed. We assessed the proportion of treatment fields with a CC length of <20 cm and the effects of gender, height, hyo-sternal neck length (distance from superior surface of hyoid to sternal notch measured on the coronal reconstruction of the planning CT) and neck position on CC length. RESULTS: 95% of HNC patients had a CC field length <20 cm. Female patients showed a significantly shorter median CC length than male patients in both extended (p = 0.0003) and neutral (p = 0.008) neck positions. Neck position influenced the median CC length with neutral neck being significantly shorter than extended neck (p = 0.0119). Patient height and hyo-sternal neck length showed positive correlation with the CC length, with neck length in neutral position having the strongest correlation (r = 0.65, p = 0.0001 and r = 0.63, p < 0.0001, respectively for extended neck; r = 0.55, p = 0.0070 and r = 0.80, p < 0.0001, respectively for neutral neck). A hyo-sternal neck length of <14.6 cm predicted a CC length of <20 cm in neutral neck position. CONCLUSION: The majority of patients with HNC at the Royal Marsden Hospital have anthropometric features compatible with their being treated on the MR-Linac using a single isocentre technique. The absolute CC field size may vary according to primary tumour site, patient factors and neck position. A hyo-sternal neck length cut-off of 14.6 cm in the neutral neck position can be used as a surrogate marker for suitability of treatment on MR-Linac. ADVANCES IN KNOWLEDGE: This paper highlights the potential impact of a restricted CC field in HNC patient selection for the MR-Linac treatment. This is the first report to suggest the use of neck length as a surrogate marker for suitability of treatment on the MR-Linac.
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Subject
Humans
Head and Neck Neoplasms
Magnetic Resonance Imaging
Anthropometry
Body Height
Radiotherapy, Adjuvant
Retrospective Studies
Sex Factors
Patient Selection
Adult
Aged
Aged, 80 and over
Middle Aged
Female
Male
Radiotherapy, Intensity-Modulated
Patient Positioning
Research team
Targeted Therapy
Targeted Therapy
Language
eng
Date accepted
2020-05-04
Citation
The British journal of radiology, 2020, 93 (1111), pp. 20200023 - ?
Publisher
BRITISH INST RADIOLOGY