Comparison of Skeletal Muscle Changes at Three Vertebral Levels Following Radiotherapy in Patients With Oropharyngeal Carcinoma

Abstract

Evaluation of skeletal muscle (SM) depletion, or sarcopenia, utilizes the cross-sectional area (CSA) of computed tomography (CT) scans at the lumbar level L3. However, alternate vertebral landmarks are used in patients with head and neck cancer due to scan unavailability. Muscle changes following radiotherapy at cervical (C3) and thoracic (T2) levels were compared to L3 in patients with oropharyngeal carcinoma. Muscle density data were derived retrospectively from diagnostic PET-CT scans at C3, T2 and L3 pretreatment, and up to six months post. CSA changes were compared to L3 in scans of 33 patients (88% male, mean age 61 (SD 8.5) years). On matched pair analysis; mean L3-CSA change −12.1 cm² (SD 9.7, 95%CI −15.5 to −8.6, and p < 0.001), T2-CSA −30.5 cm² (SD 34.8, 95%CI −42.8 to −18.1, and p < 0.001) and C3-CSA +2.1 cm² (SD 4.1, 95%CI 0.63 to 3.5, and p < 0.00). No difference was found in the percentage change of T2-CSA with L3-CSA (mean −2.2%, SD 10.6, 95%CI −6.0 to 1.6, and p = 0.240), however, was significantly different to C3-CSA (mean 13.2%, SD 11.6, 95%CI 9.1 to 17.3, and p < 0.001). Results suggest SM at C3 does not change proportionately and may not be a reliable representation of whole-body SM change over time.

Aknowledgements

The authors would like to thank Damian Kotevski from The Prince of Wales Hospital, for assistance with statistical analysis and figure development.

Disclosure statement

The authors declare that they have no known competing financial interests or personal relationships to declare.

Additional information

Funding

Support was provided for this work by an Australian Government Research Training Program Scholarship as part of a PhD.