Association Between Changes in Skeletal Muscle Quality and Prognosis in Postoperative Patients with Early Gastric Cancer.

[BACKGROUND] Identifying accurate prognostic factors is crucial for postoperative management of early gastric cancer (EGC) patients. Skeletal muscle quality (SMQ), defined by muscle density on computed tomography (CT) images, has been proposed as a novel prognostic factor. This study compared the prognostic significance of SMQ changes with the well-established factor of body weight (BW) loss in the postoperative EGC setting.

[METHODS] This single-center retrospective study included 297 postoperative EGC patients (median age 69 years, 68.4% male) who had preoperative and 1-year-postoperative gastrectomy CT images. SMQ was defined as the modified intramuscular adipose tissue content (mIMAC = skeletal muscle density-subcutaneous fat density on CT images) and the change as ΔmIMAC. Log-rank test, Kaplan-Meier survival, and Cox proportional hazards regression analyses were used to assess the associations between prognosis and either ΔmIMAC or BW change (ΔBW). Prognosis prediction by ΔmIMAC and ΔBW was compared by using the area under the curve (AUC) of the receiver operating characteristic curve.

[RESULTS] ΔmIMAC was significantly associated with prognosis (log-rank test; P = 0.037), but ΔBW was not (P = 0.243). Prognosis was significantly poorer in the severely decreased mIMAC group than in the preserved group (multivariate Cox proportional hazards regression analysis; P = 0.030) but was unaffected by BW changes (P = 0.697). The AUC indicated a higher prognostic value for ΔmIMAC than ΔBW (ΔmIMAC: AUC = 0.697, ΔBW: AUC = 0.542).

[CONCLUSIONS] One-year post-gastrectomy SMQ changes may be better prognostic EGC predictors than BW changes.