RÉSUMÉ
BACKGROUND: The association of chemotherapy-induced myelosuppression with tumor response and overall survival remained controversial. The study was conducted to investigate the association between them in small cell lung cancer (SCLC). METHODS: 204 eligible patients with SCLC were respectively included and categorized into three groups (no, mild, and severe myelosuppression) based on myelosuppression degree after the first chemotherapy. Curative efficacy of 2-cycle chemotherapy was evaluated by the objective response rate (ORR) and disease control rate (DCR). Univariate and multivariate logistic regression analyses were conducted to investigate their association. Receiver operator characteristic (ROC) curves, net reclassification index (NRI), and integrated discrimination improvement (IDI) were used to assess the predictive ability of myelosuppression. RESULTS: In the fully-adjusted model, mild (OR, 4.61; 95% CI, 1.35 to 18.27; P = 0.020) and severe (OR, 7.22; 95% CI, 1.30 to 72.44; P = 0.046) myelosuppression were positively associated with DCR. However, only mild myelosuppression was significantly associated with ORR (OR, 2.78; 95% CI, 1.30 to 6.14; P = 0.010). Although we observed evidence of increased ORR in severe myelosuppression, the difference was not statistically significant. Furthermore, based on the results of the ROC curve, NRI and IDI, chemotherapy-induced myelosuppression cannot be used as a accurate and independent predictor for curative efficacy, but it can improve overall prediction accuracy. CONCLUSION: Chemotherapy-induced myelosuppression was significantly associated with curative efficacy of 2-cycle chemotherapy in SCLC, which could help predict treatment efficacy and guide chemotherapy dosage.