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.

Autor:	Ng-Cheng-Hin B; The Institute of Cancer Research and Royal Marsden NHS Trust, Head and Neck Radiotherapy and Imaging, Sutton, United Kingdom., Nutting C; The Institute of Cancer Research and Royal Marsden NHS Trust, Head and Neck Radiotherapy and Imaging, Sutton, United Kingdom., Newbold K; The Institute of Cancer Research and Royal Marsden NHS Trust, Head and Neck Radiotherapy and Imaging, Sutton, United Kingdom., Bhide S; The Institute of Cancer Research and Royal Marsden NHS Trust, Head and Neck Radiotherapy and Imaging, Sutton, United Kingdom., McQuaid D; Joint Department of Physics, The Institute of Cancer Research and Royal Marsden NHS Trust, Sutton, United Kingdom., Dunlop A; Joint Department of Physics, The Institute of Cancer Research and Royal Marsden NHS Trust, Sutton, United Kingdom., Harrington K; The Institute of Cancer Research and Royal Marsden NHS Trust, Head and Neck Radiotherapy and Imaging, Sutton, United Kingdom., Wong KH; The Institute of Cancer Research and Royal Marsden NHS Trust, Head and Neck Radiotherapy and Imaging, Sutton, United Kingdom.
Jazyk:	angličtina
Zdroj:	The British journal of radiology [Br J Radiol] 2020 Jul; Vol. 93 (1111), pp. 20200023. Date of Electronic Publication: 2020 May 21.
DOI:	10.1259/bjr.20200023
Abstrakt:	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.
Databáze:	MEDLINE
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