Extracellular water to total body water ratio, a novel predictor of recurrence in patients with colorectal cancer.

BACKGROUND: Total body water (TBW) fraction, which accounts for 60% of body weight, is an important indicator of body composition, and the extracellular water to TBW ratio (ECW/TBW) is reportedly useful in predicting clinical outcomes of patients with organ disorders. We aimed to clarify the clinical impact of preoperative ECW/TBW status on survival outcomes in cancer patients.

METHODS: We used a database of 320 colorectal cancer (CRC) patients who underwent potentially curative resections. Preoperative ECW/TBW was measured using a bioelectrical impedance analysis (BIA), and its correlation with patient survival outcomes, clinicopathological factors, laboratory data, and comorbidities were analyzed.

RESULTS: A high preoperative ECW/TBW was significantly associated with poorer relapse-free survival (RFS; p  = 0.001) and overall survival (OS; p  = 0.003). A high ECW/TBW ratio was significantly associated with older age ( p  < 0.001), low BMI ( p  = 0.009), and right-sided tumors ( p  = 0.03). In a multivariate analysis, a high ECW/TBW significantly predicted a higher RFS mortality (HR: 2.07, 95% CI: 1.10-3.88, p  = 0.024) and OS mortality (HR: 3.23, 95% CI: 1.25-8.36, p  = 0.016). Furthermore, a high ECW/TBW was significantly associated with lower hemoglobin ( p  < 0.001) and albumin levels ( p  < 0.001), but not comorbidities.

CONCLUSIONS: A high preoperative ECW/TBW was a predictive factor for recurrence and poorer overall survival independent of the tumor, node, and metastasis (TNM) stage. Our data suggest that preoperative evaluation of ECW/TBW using BIA might serve as a novel tool for developing CRC treatment strategies.