Early postoperative body-composition trajectories and exploratory ratio-defined phenotypes after laryngectomy for laryngeal cancer: a prospective cohort study.

PURPOSE: To characterize early postoperative trajectories of skeletal muscle mass and fat mass after laryngectomy for laryngeal cancer and secondarily explore ratio-defined relative body-composition phenotypes.

METHODS

In this prospective cohort, 230 patients underwent bioelectrical impedance analysis (BIA) within 48 h of admission and at postoperative weeks 1, 2, 4, and 8. BIA measured skeletal muscle mass index (SMI) and fat mass index (FMI). The week 2 ratio R = 100 × (ΔSMI₂w/ΔFMI₂w) described relative compartmental change; the cohort median (- 22.1%) was used as an exploratory cutoff for fat mass-dominant type (FMDT) and skeletal muscle mass-dominant type (SMDT). Factors associated with FMDT were examined using multivariable logistic regression.

RESULTS

FMI decreased early and returned toward baseline by week 8, whereas SMI changed little at week 1, declined thereafter, and remained below baseline at week 8. FMDT and SMDT each included 115 patients (50.0%). Compared with well-differentiated tumors, moderately and poorly differentiated tumors were associated with FMDT (odds ratio [OR] 2.452, 95% confidence interval [CI] 1.229-4.893; OR 2.507, 95% CI 1.094-5.746). Higher preoperative body fat mass was associated with lower odds of FMDT (OR 0.939, 95% CI 0.893-0.988).

CONCLUSION

FMI and SMI showed distinct postoperative trajectories. Ratio-defined FMDT/SMDT described exploratory relative compartmental-change patterns, and pathological differentiation and preoperative body fat mass were associated with FMDT. These findings require confirmation in independent cohorts before clinical interpretation.