Weight loss versus muscle loss: re-evaluating inclusion criteria for future cancer cachexia interventional trials

Participation in cancer cachexia clinical trials requires a defined weight loss (WL) over time. A loss in skeletal muscle mass, measured by cross-sectional computed tomography (CT) image analysis, represents a possible alternative. Our aim was to compare WL versus muscle loss in patients who were screened to participate in a cancer cachexia clinical trial. This was a single-center, retrospective analysis in metastatic colorectal cancer patients screened for an interventional cancer cachexia trial requiring a ae5 % WL over the preceding 6 months. Concurrent CT images obtained as part of standard oncology care were analyzed for changes in total muscle and fat (visceral, subcutaneous, and total). Of patients screened (n = 36), 3 (8 %) enrolled in the trial, 17 (47 %) were excluded due to insufficient WL (< 5 %), 3 (8 %) were excluded due to excessive WL (> 20 %), and 16 (44 %) met inclusion criteria for WL. Patients who met screening criteria for WL (5-20 %) had a mean +/- SD of 7.7 +/- 8.7 % muscle loss, 24.4 +/- 37.5 % visceral adipose loss, 21.6 +/- 22.3 % subcutaneous adipose loss, and 22.1 +/- 24.7 % total adipose loss. Patients excluded due to insufficient WL had 2 +/- 6.4 % muscle loss, but a gain of 8.5 +/- 39.8 % visceral adipose, and 4.2 +/- 28.2 % subcutaneous adipose loss and 0.8 +/- 28.4 % total adipose loss. Of the patients excluded due to WL < 5 % (n = 17), 7 (41 %) had a skeletal muscle loss > 5 %. Defining cancer cachexia by WL over time may be limited as it does not capture skeletal muscle loss. Cross-sectional CT body composition analysis may improve early detection of muscle loss and patient participation in future cancer cachexia clinical trials.