Baseline and longitudinal quantification of lean muscle mass using routine CT measurements prior to resection for pancreatic adenocarcinoma.

Abstract

198 Background: When compared to healthy populations subjects are defined as sarcopenic if they have severe loss of lean muscle mass (LMM). Sarcopenia is associated with poor outcomes in some studies of pancreatic cancer (PDA) but the prevelance remains uncertain in resected patients and there is little data about changes in LMM during neoadjuvant chemotherapy. Muscle mass can be reliably quantified in cancer patients using routine imaging. We analyzed a large cohort of patients undergoing surgery at a high-volume center to quantify LMM at baseline and with treatment, and to determine the association of sarcopenia with tumor histology and outcomes. Methods: We analyzed subjects undergoing surgery for PDA at the Pancreas Center at Columbia University from 2011-2014. We utilized CT scans to measure cross sectional area of muscle at the L3 vertebral body (LMM in cm2) and used height to define a smooth muscle index (SMI-cm/m). Sarcopenia was determined based on SMI < 38.9 for females and < 55.4 for males. In subjects undergoing neoadjuvant chemotherapy, SMI was also calculated on post therapy scans. We collected information on clinical and pathological variables and performed statistical analyses utilizing SAS 9.4 software. Results: Among subjects with available imaging (n = 106) sarcopenia rates at initial staging were high whether they were immediately resectable (52%) or locally advanced (63%). Rates of sarcopenia were higher in males than females (77 vs 38%, p < 0.001). Sarcopenic status was not correlated with survival, tumor stage or grade but was associated with age, gender, and BMI. Among locally advanced subjects who proceeded to surgery after neoadjuvant chemotherapy (n = 40) there was no change in SMI or incidence of sarcopenia following treatment (median 171 days). Conclusions: Sarcopenia is highly prevalent at diagnosis in subjects undergoing surgery for PDA but was not associated with survival, tumor grade or stage in this cohort. Subjects who successfully completed neoadjuvant treatment did not experience significant loss in LMM despite extensive treatment suggesting that lack of change in LMM may assist in predicting favorable response to neoadjuvant therapy in PDA.