Skeletal Muscle Depletion Predicts the Prognosis of Patients with Advanced Pancreatic Cancer Undergoing Palliative Chemotherapy, Independent of Body Mass Index

Abstract

Introduction: Body composition has emerged as a prognostic factor in cancer patients. We investigated whether sarcopenia at diagnosis and loss of skeletal muscle during palliative chemotherapy were associated with survival in patients with pancreatic cancer.

Methods: We retrospectively reviewed the clinical outcomes of pancreatic cancer patients receiving palliative chemotherapy between 2003 and 2010. The cross-sectional area of skeletal muscle at L3 by computed tomography was analyzed with Rapidia 3D software. We defined sarcopenia as a skeletal muscle index (SMI)< 42.2 cm2/m2 (male) and < 33.9 cm2/m2 (female) using ROC curve.

Results: Among 484 patients, 103 (21.3%) patients were sarcopenic at diagnosis. Decrease in SMI during chemotherapy was observed in 156 (60.9%) male and 65 (40.6%) female patients. Decrease in body mass index (BMI) was observed in 149 patients (37.3%), with no gender difference. By multivariate analysis, sarcopenia (P< 0.001), decreasedBMI and SMI during chemotherapy (P = 0.002, P = 0.004, respectively) were poor prognostic factors for overall survival (OS). While the OS of male patients was affected with sarcopenia (P< 0.001) and decreased SMI (P = 0.001), the OS of female patients was influenced with overweight at diagnosis (P = 0.006), decreased BMI (P = 0.032) and decreased SMI (P = 0.014). Particularly, while the change of BMI during chemotherapy did not have impact on OS within the patients with maintained SMI (P = 0.750), decrease in SMI was associated with poor OS within the patients with maintained BMI (HR 1.502; P = 0.002).

Conclusions: Sarcopenia at diagnosis and depletion of skeletal muscle, independent of BMI change, during chemotherapy were poor prognostic factors in advanced pancreatic cancer.

Fig 1. Computed tomography images of the region of the third lumbar vertebra, with skeletal muscle highlighted in blue (-29 to 150 Hounsfield units).

The blue line on the three-dimensionally reconstructed image on the left indicates the level of the third lumbar vertebra, which is shown in the axial view on the right.

Fig 2. ROC curve ofsarcopenia for both genders.

Fig 3. Survival according to skeletal muscle index.

Initial SMI was related to worse prognosis (A) for the entire patients (HR 1.721; P < 0.001); (B) for the male patients (HR 1.736; P < 0.001); (C) not for female patients (P = 0.299).

Fig 4. Survival according to change in body mass indexand skeletal muscle index.

BMI decreased by more than 1 kg/m² and SMI decreased by more than 2 cm²/m² were strongly related to worseoutcome. Decrease of BMI (A) for the entire patients (HR 1.452; P = 0.002); (B) for the male patients (HR 1.218; P = 0.142); (C) for the female patients (HR 1.464; P = 0.032). Decrease of SMI (D) for the entire patients (HR 1.390;P = 0.004); (E) for the male patients (HR 1.560; P = 0.001); (F) for the female patients (HR 1.521; P = 0.014).