The Factors Reducing Relative Dose Intensity of Cisplatin and Vinorelbine as Adjuvant Chemotherapy in Patients with Non-Small Cell Lung Cancer

Purpose Adjuvant therapy with cisplatin and vinorelbine (CV therapy) is recommended for patients after complete surgical resection of stage II and IIIA non-small cell lung cancer (NSCLC). However, a dose reduction or early discontinuation of a subsequent course of treatment is a frequent clinical problem. The aim of this study was to investigate the factors reducing the relative dose intensity (RDI) of adjuvant CV therapy in patients with NSCLC. Methods Patients who had received CV as an adjuvant chemotherapy for NSCLC at the Osaka City University Hospital between July 2007 and March 2016 were identified from medical records. The patients were classified into two groups (RDI <50% and RDI ≥50%, respectively), and patients’ characteristics, laboratory values, adverse reactions, and RDI of CV therapy were analyzed. The two groups were compared using the Fisher's exact test. Results The study population consisted of 25 patients. There were six patients (24.0%) with RDI <50% and 19 patients (76.0%) with RDI ≥50%. Univariate analysis showed that the use of calcium channel blockers [crude odd ratio (OR): 10.70; 95% confidence interval (CI): 1.31–86.94; p=0.032] and renal dysfunction (creatinine clearance <60 mL/min) (crude OR: 18.00; 95% CI: 1.37–235.70; p=0.031) were associated with the reduced RDI. Conclusion This study indicated that the renal dysfunction and concomitant use of calcium channel blockers might be predictive factors for reduced RDI of adjuvant CV therapy in patients with NSCLC. Patients with these factors may be able to avoid extreme reduction in RDI if the dose is reduced or the dosing interval is prolonged.