Abstract Background Postoperative complications have been linked to the morbidity and mortality of several cancers. However, predicting whether complications will occur in the early period after surgery or not is challenging. Hence, this study aimed to examine the diagnostic accuracy of serum creatine phosphokinase (CPK) and c-reactive protein (CRP) in predicting the development of postgastrectomy complications. Methods We retrospectively analyzed 188 patients with gastric cancer (GC) who underwent gastrectomy. The diagnostic accuracy of serum CPK and CRP was investigated using the areas under the curves (AUC). The CPK ratio was defined as the CPK on postoperative day (POD) 1 to the CPK on a preoperative day. Results Out of 188 patients, 48 (25.5%) developed postoperative complications. The complications group had a greater operative time (p = 0.037), higher CPK ratio on POD1 (p < 0.0001), and a higher serum CRP level on POD3 (p = 0.001). The AUC for the CPK ratio was 0.772, with an optimal cutoff value of 7.05, whereas that for CRP was 0.659, with an optimal cutoff value of 11.4 mg/L. The CPK ratio on POD1 (p < 0.0001) and the CRP on POD3 (p = 0.007) were independent factors for predicting the development of postgastrectomy complications. The CPK ratio on POD1 and the CRP on POD3 predicted postgastrectomy complications in 41 patients (85.4%). According to combined value of both CPK ratio and CRP level, the positive predictive value and the negative predictive value was 0.70 and 0.829. And sensitivity and specificity were 0.438 and 0.936. Conclusion The CPK ratio on POD1 and the CRP on POD3 after gastrectomy for GC were predictive factors for complication development and may be employed to prevent the development of such complications and improve the prognosis of patients with GC.
