Utility of creatinine/cystatin C ratio as a predictive marker for adverse effects of chemotherapy in lung cancer: A retrospective study

Objective To determine whether the creatinine/cystatin C (Cr/CysC) ratio, which is influenced by muscle mass, can be used as a predictive marker of the adverse effects of chemotherapy. Methods This single-centre, retrospective, observational study assessed patients with lung cancer. Serum Cr and CysC levels were measured once within 1 month prior the commencement of chemotherapy. Results A total of 25 patients with lung cancer were enrolled in the study: 22 received first-line therapy; three received second-line therapy. A significant difference was noted regarding the Cr/CysC ratios between patients with nonsmall-cell lung cancer (NSCLC) and those with small-cell lung cancer (0.78 versus 0.92, respectively). A significant difference was also noted in the Cr/CysC ratios of patients with NSCLC with toxicity grades <3 and ≥3 (0.84 versus 0.70, respectively). Similar findings were observed in patients with NSCLC who received platinum-based combination therapy (toxicity grade < 3, 0.85; toxicity grade ≥3, 0.69). Conclusion The Cr/CysC ratio could serve as a useful predictive marker for chemotherapy-related adverse effects in patients with NSCLC.