Abstract 1632P
Background
Previous reports suggest sarcopenia affects prognosis and treatment tolerance in patients with various solid cancers. Though it is reported that regorafenib could be associated with increased skeletal muscle loss which relate to poor prognosis in metastatic colorectal cancer patients, it is not well established in gastrointestinal stromal tumors (GISTs). Here we evaluated the impact of regorafenib treatment on skeletal muscle dynamics in GIST patients.
Methods
We retrospectively analyzed the clinical data with GISTs patients who received regorafenib monotherapy in Hokkaido University Hospital. The skeletal muscle index (SMI, cm2/m2) and sarcopenia were evaluated from cross-sectional CT images at the level of the third lumbar vertebra. Sarcopenia was defined BMI-incorporated cutoff values of SMI as <43 cm2/m2 for males with BMI < 25 kg/m2, <53 cm2/m2 for males with BMI ≥ 25 kg/m2, and <41 cm2/m2 for females. The SMI assessments were performed just before regorafenib initiation and within 3 months after regorafenib initiation.
Results
We analyzed 15 patients who had received regorafenib between January 2013 and February 2019. At the baseline, 8 (53.3%) of them presented with sarcopenia. A statistically significant skeletal muscle loss was observed after regorafenib initiation (median SMI change: -4.8 cm2/m2 [-6.3%]; P = .0005). We classified the patients into 3 groups—normal muscle mass, new-onset sarcopenia, and stable sarcopenia after regorafenib initiation. One-year overall survival rates of these groups were 100% (2/2 patients), 60% (3/5 patients), and 50% (4/8 patients), respectively (P = 0.762).
Conclusions
Regorafenib could be associated with increased skeletal muscle loss in GIST patients. It should be used with caution in the patients with preexisting sarcopenia or a history of recent weight.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.