HNSCC Survival Linked To Pre- And Post-Radiotherapy Skeletal Muscle Depletion

Measurement of skeletal muscle loss may identify head and neck squamous cell carcinoma patients at risk of a poor outcome after curative radiotherapy

medwireNews: Head and neck squamous cell carcinoma (HNSCC) patients with skeletal muscle (SM) mass depletion before or after radiotherapy (RT) are at risk of poor survival, study findings suggest.

The research "makes a provocative case for the importance of body composition in predicting survival after definitive RT", say Clifton Fuller, from the University of Texas MD Anderson Cancer Center in Houston, USA, and co-authors in JAMA Oncology.

Whole-body positron emission tomography (PET)–computed tomography (CT) or abdominal CT scans taken of 190 patients before curative RT revealed SM depletion, defined as a lumbar SM index of less than 52.4 and 38.5 for men and women, respectively, in 35.3% and in an additional 30.5% of participants after treatment.

Patients with evidence of SM depletion before treatment, had significantly poorer overall survival (OS) and disease-specific survival (DSS) than those who did not, with significant hazard ratios (HRs) of 1.92 and 1.87, respectively. And 5-year OS fell from 75% in patients with no SM depletion prior to treatment to 62% for patients with such SM loss.

OS was also significantly lower for patients who showed SM depletion after RT compared with those who maintained their muscle mass, with a HR of 2.03, and a 5-year fall in OS rate from 86% to 64%. Patients with post-treatment SM loss were also significantly more likely to have locoregional recurrence than those without (HR=3.0).

Further analysis confirmed the impact of pre-RT SM loss on OS in patients with non-oropharyngeal HNSCC but not in those with oropharyngeal disease. Post-RT loss predicted a significant decrease in OS for both tumour types but more strongly for non-oropharyngeal patients.

The researchers also found that an overall weight loss of 5% or more was associated with a trend towards better survival, although this was not significant. Patients with higher body mass index (BMI) had significantly better overall survival (HR=0.91 per 1 U increase), largely driven by better disease-specific survival and improved locoregional control.

Although BMI category had no impact on OS, overweight and obese patients had better DSS than their healthy BMI counterparts, and locoregional control was better in obese than healthy BMI patients.

Multivariate analyses adjusting for confounding factors, such as cancer stage, and patient age and gender, confirmed that pre- and post-RT SM loss and baseline BMI were significant predictors of OS, with BMI the strongest performing factor, followed by post-treatment SM loss.

"Skeletal muscle mass and BMI each demonstrate increased prognostic value, compared with weight loss, and therefore may more accurately distinguish patients who benefit from nutritional supplementation", suggestClifton Fuller and team.

"Our data suggest BMI or SM mass can be used to stratify patients with HNSCC undergoing curative RT by risk, but this should be confirmed in prospective trials."

Reference

Grossberg AJ, Chamchod S, Fuller CD, et al. Association of body composition with survival and locoregional control of radiotherapy-treated head and neck squamous cell carcinoma. JAMA Oncol 2016; Advance online publication 18 February.doi:10.1001/jamaoncol.2015.6339

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