Temporal changes in skeletal muscle index dataset for colorectal malignancy recurrence study

This dataset comprises de-identified, retrospective clinical and imaging data for patients diagnosed with locally advanced (stage III) colorectal cancer who underwent curative surgical resection at a single institution between 2000 and 2020. For each patient, skeletal muscle index (SMI) measurements were derived from routine abdominal CT scans at the third lumbar vertebral level. SMI was assessed at two timepoints: initially at diagnosis (preoperative baseline), and at a follow-up timepoint matched to the date of cancer recurrence. Patients without recurrence were paired to those with recurrence through propensity score matching incorporating the duration between scans, smoking/radiation/chemotherapy status, tumor histology, primary cancer site and AJCC tumor staging as covariates. The dataset supports investigations into the prognostic value of temporal SMI tracking and includes relevant variables used for evaluating SMI trends based on recurrence status. Key findings from the associated study indicate that a decline in skeletal muscle index postoperatively is independently associated with an increased risk of cancer recurrence, suggesting that SMI decline may serve as a clinically useful biomarker to personalize postoperative surveillance and risk stratification.