Longitudinal Association Between the Change in Serum Procollagen Type III N-Terminal Peptide (PIIINP) and Skeletal Muscle Loss in Patients with Gastrointestinal Cancer Receiving Chemotherapy: A Prospective Cohort Study.

Background/

Objectives

Sarcopenia predicts increased morbidity and mortality in gastrointestinal (GI) cancer. This study evaluated the longitudinal association between changes in the skeletal muscle index (SMI) and serum procollagen type III N-terminal peptide (PIIINP), together with sarcopenia and malnutrition screening tools (SARC-F, SARC-CalF, MUST), during chemotherapy for GI cancer.

Methods

In this prospective single-center study, 170 patients with GI cancer were assessed at baseline and month 6; 48 died, and longitudinal analyses included the 122 survivors. SMI was derived from bioelectrical impedance analysis (Tanita SC-330) using the Janssen equation, and serum PIIINP was measured at both time points. The primary endpoint was the association between the percentage changes in SMI and PIIINP.

Results

BMI, SMI, and handgrip strength decreased and SARC-F and SARC-CalF scores increased significantly (all p < 0.001); the prevalence of low muscle mass rose from 29% to 52%, and PIIINP increased significantly. The percentage changes in SMI and PIIINP were strongly inversely correlated (ρ = -0.733, p < 0.001). In the parsimonious multivariable model, the percentage change in PIIINP (β = -0.47) and month-6 albumin (β = 0.31) were independently associated with the change in SMI (R2 = 0.37); the albumin association was model-dependent and not retained in the expanded model.

Conclusions

In patients with GI cancer receiving chemotherapy, progressive muscle loss over six months was accompanied by a rise in the circulating collagen turnover marker PIIINP. Because the study was observational, restricted to survivors, and based on a non-muscle-specific marker, causal and muscle-specific inferences are unwarranted; PIIINP nonetheless merits further evaluation as a monitoring biomarker.