Background : Cachexia is pervasive in pancreatic cancer (PC) patients, with a prevalence of approximately 80-85%, ranking the highest among all cancer types. The prognostic significance of Skeletal Muscle Index (SMI) in elucidating malignant biological behavior and predicting outcomes in surgical PC patients remains incompletely understood.

Methods : This retrospective investigation was conducted at Zhongshan Hospital, Fudan University, a high-volume pancreatic surgery center. A cohort comprising 333 consecutive patients who underwent surgery for PDAC between January 2020 and December 2021 was examined. Precise quantification of SMI was performed on skeletal muscle areas at the third lumbar vertebra from CT scans. Comprehensive analyses were undertaken to elucidate the interplay between SMI and clinicopathological parameters, including clinical features and prognostic outcomes.

Results : The threshold values for SMI were 42.39 for male PC patients and 39.42 for female PC patients. Among the 333 patients enrolled, 85(25.53%) and 248(74.47%) were categorized as non-sarcopenic and sarcopenic, respectively. Significantly advanced age and compromised nutritional status (indicated by lower hemoglobin and prealbumin levels) was observed in sarcopenic patients (p<0.001). Furthermore, sarcopenic patients exhibited a higher incidence of KRAS mutations (p<0.05). Perturbations in glucose metabolism were discerned, albeit not statistically significant (glucose, insulin, and c-peptide, p<0.1). Notably, occurrence of post-surgical complications, including postoperative pancreatic fistula, delayed gastric emptying, and post-pancreatectomy hemorrhage were comparable between non-sarcopenic and sarcopenic groups.

Conclusions : Although it is safe for sarcopenic patients to undergo surgery, they display a distinct clinicopathological profile, possibly accounting for impaired prognostic outcomes. The SMI emerges as a valuable metric, offering informative insights for PC prognostication.