Validation of skeletal muscle mass assessment at the level of the third cervical vertebra in patients with head and neck cancer

BACKGROUND

Low skeletal muscle mass (SMM) is associated with adverse outcomes. SMM is often assessed at the third lumbar vertebra (L3) on abdominal imaging. Abdominal imaging is not routinely performed in patients with head and neck cancer (HNC). We aim to validate SMM measurement at the level of the third cervical vertebra (C3) on head and neck imaging.

MATERIAL AND METHODS

Patients with pre-treatment whole-body computed tomography (CT) between 2010 and 2018 were included. Cross-sectional muscle area (CSMA) was manually delineated at the level of C3 and L3. Correlation coefficients and intraclass correlation coefficients (ICCs) were calculated. Cohen's kappa was used to assess the reliability of identifying a patient with low SMM.

RESULTS

Two hundred patients were included. Correlation between CSMA at the level of C3 and L3 was good (r = 0.75, p < 0.01). Using a multivariate formula to estimate CSMA at L3, including gender, age, and weight, correlation improved (r = 0.82, p < 0.01). The agreement between estimated and actual CSMA at L3 was good (ICC 0.78, p < 0.01). There was moderate agreement in the identification of patients with low SMM based on the estimated lumbar skeletal muscle mass index (LSMI) and actual LSMI (Cohen's κ: 0.57, 95%CI 0.45-0.69).

CONCLUSIONS

CSMA at C3 correlates well with CSMA at L3. There is moderate agreement in the identification of patients with low SMM based on the estimated lumbar SMI (based on measurement at C3) and actual LSMI.

Skeletal muscle mass is an imaging biomarker for decreased survival in patients with oropharyngeal squamous cell carcinoma

OBJECTIVES

Low skeletal muscle mass (SMM) and sarcopenic obesity (co-presence of low SMM and obesity) are emerging prognosticators in oncology, but the prevalence and prognostic value in oropharyngeal squamous cell carcinoma (OPSCC) is not yet known.

MATERIALS AND METHODS

Patients with OPSCC, curative treatment intention and pre-treatment diagnostic imaging of the head and neck area were included. Patients with unknown HPV-status, palliative treatment intention or unavailable imaging were excluded, Relevant demographic and clinical characteristics were collected between 2009 and 2016. Patients were stratified into a low-, intermediate-, and high-risk group according to HPV-status, amount of pack-years, tumor and nodal stage. SMM was radiologically measured and cutoff values were determined by optimal stratification. The prognostic value of low SMM and sarcopenic obesity for overall survival (OS) and disease-free survival (DFS) was determined by Cox regression analysis and Kaplan Meier survival curves.

RESULTS

In 216 patients, low SMM and sarcopenic obesity were present in 140 (64.8%) and 13 (6.0%) patients, respectively. On multivariate analysis, stratification into a high-risk group (HPV-negative status with ≥10-pack-years or T4-stage) was a prognostic factor for OS and DFS (HR 2.93, p < 0.01) (HR 4.66, p < 0.01). Of specific interest, sarcopenic obesity was a strong negative prognostic factor for OS and DFS (HR 4.42, p < 0.01 and (HR 3.90, p < 0.05), independent from other well-known prognostic factors such as HPV-status.

CONCLUSION

Low skeletal muscle mass is highly prevalent in OPSCC patients. Sarcopenic obesity is a novel pretreatment prognosticator for OS and DFS in OPSCC and should therefore be considered in clinical decision making.

Interobserver agreement of skeletal muscle mass measurement on head and neck CT imaging at the level of the third cervical vertebra

OBJECTIVES

Skeletal muscle mass (SMM) is most often assessed in cancer patients on abdominal computed tomography (CT) imaging at the level of the third lumbar vertebra (L3). Abdominal CT imaging is not routinely performed in head and neck cancer (HNC) patients. Recently, a novel method to assess SMM on a single transversal CT slice at the level of the third cervical vertebra (C3) was published. The objective of this study was to assess the robustness of this novel C3 measurement method in terms of interobserver agreement.

PATIENTS AND METHODS

Patients diagnosed with locally advanced head and neck squamous cell carcinoma (LA-HNSCC) at our center between 2007 and 2011 were evaluated. Fifty-four patients with were randomly selected for analysis. Six observers independently measured the cross-sectional muscle area (CSMA) at the level of C3 using a predefined, written protocol as instruction. Interobserver agreement was assessed using intraclass correlation coefficients (ICCs), a Bland-Altman plot and Fleiss' kappa (κ).

RESULTS

The agreement in vertebra selection between all observers was excellent (Fleiss' κ: 0.96). There was a substantial agreement between all observers in single slice selection (Fleiss' κ: 0.61). For all CSMA measurements, ICCs were excellent (0.763-0.969; all p < 0.001). The Bland-Altman plot showed good agreement between measurements, with narrow limits of agreement.

CONCLUSION

Interobserver agreement for SMM measurement at the level of C3 was excellent. Assessment of SMM at the level of C3 is easy and robust and can performed on routinely available imaging in HNC patients.