Impact of sarcopenia on outcomes following resection of pancreatic adenocarcinoma

Abstract

Introduction: Assessing patient-specific risk factors for long-term mortality following resection of pancreatic adenocarcinoma can be difficult. Sarcopenia--the measurement of muscle wasting--may be a more objective and comprehensive patient-specific factor associated with long-term survival.

Methods: Total psoas area (TPA) was measured on preoperative cross-sectional imaging in 557 patients undergoing resection of pancreatic adenocarcinoma between 1996 and 2010. Sarcopenia was defined as the presence of a TPA in the lowest sex-specific quartile. The impact of sarcopenia on 90-day, 1-year, and 3-year mortality was assessed relative to other clinicopathological factors.

Results: Mean patient age was 65.7 years and 53.1 % was male. Mean TPA among men (611 mm²/m²) was greater than among women (454 mm²/m²). Surgery involved pancreaticoduodenectomy (86.0 %) or distal pancreatectomy (14.0 %). Mean tumor size was 3.4 cm; 49.9 % and 88.5 % of patients had vascular and perineural invasion, respectively. Margin status was R0 (59.0 %) and 77.7 % patients had lymph node metastasis. Overall 90-day mortality was 3.1 % and overall 1- and 3-year survival was 67.9 % and 35.7 %, respectively. Sarcopenia was associated with increased risk of 3-year mortality (HR = 1.68; P < 0.001). Tumor-specific factors such as poor differentiation on histology (HR = 1.75), margin status (HR = 1.66), and lymph node metastasis (HR = 2.06) were associated with risk of death at 3-years (all P < 0.001). After controlling for these factors, sarcopenia remained independently associated with an increased risk of death at 3 years (HR = 1.63; P < 0.001).

Conclusions: Sarcopenia was a predictor of survival following pancreatic surgery, with sarcopenic patients having a 63 % increased risk of death at 3 years. Sarcopenia was an objective measure of patient frailty that was strongly associated with long-term outcome independent of tumor-specific factors.

Fig. 1

TPA was measured at the level of L3 on the first image with both vertebral spines visible. Measurements were performed in a semi-automated fashion with manual outlining of psoas muscle borders and setting the density threshold between −30 and 110 Hounsfield Units (HU)

Fig. 2

a When stratified by gender, the mean adjusted TPA was statistically lower for women than for men (454.3 mm²/m² vs. 611.0 mm²/m², P<0.001). b Age tended to be associated with the incidence of sarcopenia as there was a trend toward decreasing TPA with increasing age

Fig. 3

The presence of sarcopenia was also associated with the risk of death (no sarcopenia, 18.0 months; 40.0 % vs. sarcopenia, 13.7 months; 23.0 % median, 3-year survival, respectively; P=0.01)