Loss of Skeletal Muscle Before or After Radiotherapy Linked to Poorer Survival in Head and Neck Squamous Cell Carcinoma
In a single-center retrospective study reported in JAMA Oncology, Grossberg et al found that skeletal muscle loss before or after radiotherapy was associated with poorer overall survival in patients with head and neck squamous cell carcinoma.
Study Details
The study included 2,840 patients undergoing curative radiotherapy at The University of Texas MD Anderson Cancer Center between October 2003 and August 2013. Of them, 190 had computed tomography (CT) scans before and after radiotherapy available for analysis of skeletal muscle mass. Skeletal muscle depletion was defined as a CT-measured L3 index < 52.4 cm2/m2.
Outcomes With Skeletal Muscle Depletion
Skeletal muscle depletion was found in 67 patients (35.3%) before radiotherapy and in an additional 58 patients (30.5%) after radiotherapy. Skeletal muscle depletion vs no depletion before radiotherapy was associated with significantly reduced overall survival (hazard ratio [HR] = 1.92, P = .007) and disease-specific survival (HR = 1.87, P = .03); 5-year overall survival was 62% vs 75%. No significant difference in locoregional control was observed (HR = 1.38, P = .34).
Skeletal muscle depletion after radiotherapy was associated with significantly reduced overall survival (HR = 2.03, P = .04), with a 5-year survival of 64% vs 86%. Disease-specific survival was nonsignificantly reduced (HR = 2.07, P = .09), and the risk of locoregional recurrence was significantly increased (HR = 3.00, P = .02).
Weight Loss and Body Mass Index
Weight loss was not significantly associated with overall survival among all patients or among those with normal skeletal muscle at baseline. Patients with skeletal muscle depletion before radiotherapy had significantly less weight loss than those with postradiotherapy depletion and those with skeletal muscle that remained normal.
Greater body mass index was associated with significantly greater overall survival (HR = 0.91, P < .001, per 1 unit increase). In multivariate-risk models, postradiotherapy skeletal muscle depletion had greater prognostic value than weight-based variables, but baseline body mass index exhibited the greatest prognostic value.
The investigators concluded: “Diminished [skeletal muscle] mass assessed by CT imaging or body mass index can predict oncologic outcomes for patients with head and neck squamous cell carcinoma, whereas weight loss after radiotherapy initiation does not predict [skeletal muscle] loss or survival.”
The study was supported by the National Cancer Institute; Southwest Oncology Group Hope Foundation; an Elekta AB/MD Anderson Consortium Seed Grant; and an In-Kind Award from the GE Medical Systems/MD Anderson Center for Advanced Biomedical Imaging, the MD Anderson Cancer Center, the American Cancer Society, and the Koningin Wilhemina Fonds/René Vogels Foundation.
Clifton D. Fuller, MD, PhD, of The University of Texas MD Anderson Cancer Center, is the corresponding author of the JAMA Oncology article.
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