Clinical impact of preoperative and postoperative sarcopenia on oncological outcomes in non‐metastatic colorectal cancer

This study investigated the association between preoperative and postoperative changes in skeletal muscle mass and long-term oncological outcomes in patients with non-metastatic colorectal cancer.Patients who underwent surgery for Stages I-III colorectal cancer from January 2014 to December 2015 were included. Skeletal muscle mass was evaluated through preoperative and postoperative abdominopelvic CT scans. A multivariable analysis was conducted to determine the factors affecting disease-free survival rates.A total of 238 patients were analysed. Forty-nine (25.9%) patients had preoperative sarcopenia. Patients with preoperative sarcopenia showed lower 3-year disease-free survival (58.5% vs. 78.4%, P = 0.001). Patients with postoperative sarcopenia also showed significantly lower 3-year disease-free survival compared to postoperative patients without sarcopenia at 6, 12 and 18 months, respectively (53.9% vs. 77.8%; 69.7% vs. 81.8%; 69.1% vs. 87.7%, P = 0.004). In a subgroup analysis, patients with both preoperative and postoperative sarcopenia showed the lowest 3-year disease-free survival rates (50.9%). The incidence of tumour recurrence was higher among the patients who had lost more skeletal muscle mass at 12, 18 and 24 months (-14.3 cm2 /m2 vs. -1.5 cm2 /m2 , P < 0.001; -24.5 cm2 /m2 vs. -1.1 cm2 /m2 , P < 0.001; and -31.6 cm2 /m2 vs. -1.4 cm2 /m2 , P < 0.001, respectively). A multivariable analysis demonstrated that the factors associated with disease-free survival included tumour stage, venous invasion, adjuvant chemotherapy, and preoperative or postoperative sarcopenia.Not only preoperative but also postoperative sarcopenic changes adversely affect oncological outcomes following curative resection of colorectal cancer. Careful attention should be given to correcting sarcopenic status from the preoperative to the postoperative period.