A clinically applicable muscular index predicts long-term survival in resectable pancreatic cancer
The relationship between myopenia, nutritional status, and long-term oncologic outcomes remains poorly characterized in patients with clinically resectable pancreatic cancer. We sought to reliably quantify prognostic indicators of preoperative cachexia in a manner applicable to any clinical setting.Methods.
Preoperative computed tomographies were available electronically and suitable for analysis in 73 of 82 consecutive patients with pancreatic cancer undergoing pancreatoduodenectomy between November 2010 and February 2014. The psoas index was computed from the cross-sectional area of the psoas muscles normalized to vertebral body area at the third lumbar vertebra. Correlation and proportional hazards analyses were performed to identify relationships between muscularity, preoperative nutritional markers, clinicopathologic parameters, and long-term survival.Results.
The psoas index correlated strongly with preoperative hemoglobin and albumin levels (P = .001 and .014, respectively) identifying a pattern of preoperative frailty. High psoas index and the albumin and hemoglobin levels were associated with improved long-term survival (hazard ratio 0.014, P < .001; hazard ratio 0.43, P < .001; and hazard ratio = 0.80, P = .014); however, on multivariate analysis, the psoas index proved to be the only independent predictor of survival (hazard ratio 0.021; P = .003). Rapid decreases in the psoas index during neoadjuvant chemotherapy were associated with poor postoperative outcomes, as were decreases in the psoas index during the postoperative period.Conclusion.
The data indicate that the psoas index, a calculation derived from a clinically mandated, preoperative computed tomography, is a statistically powerful and easily calculated predictor of survival in pancreatic cancer when compared to tumor grade and stage as well as previously validated nutritional parameters.