Fig. 5

Receiver operating characteristic curve analysis of Δ serum markers and overall survival of patients with interstitial lung disease induced by anticancer agents. a Receiver operating characteristic (ROC) curve analyses to determine the optimal cut off values of ΔKL-6 (blue line) and ΔSP-D (red line) for predicting survival in patients with ILD-AA. Sensitivity, or true positive rate, is plotted on the y-axis, and false positive rate, or 1-specificity, on the x-axis. The area under the curve (AUC) is equivalent to the numerator of the Mann-Whitney U statistic comparing the marker distributions between the survival and the death group after diagnosis of ILD-AA (AUC, 0.825; 95% Confidence interval (CI), 0.68–0.97; p = 0.001). The optimal cut off value of ΔSP-D was 398 ng/mL, with a sensitivity, specificity, and likelihood ratio of 42.86%, 95.55%, and 9.52, respectively. The AUC is equivalent to the numerator of the Mann-Whitney U statistic comparing the marker distributions between the survival and the death group after the onset of ILD-AA (AUC, 0.669; 95% CI, 0.48–0.85; p = 0.092). The optimal cut off value for ΔKL-6 was 219 U/mL, with a sensitivity, specificity and likelihood ratio of 78.57%, 63.64%, and 2.16, respectively. b Survival time in total patients. Median survival time (MST) was 93 days in all patients diagnosed with ILD-AA (95% CI 36–174). c Difference of survival time between high and low ΔSP-D. Survival time for patients with low ΔSP-D was significantly longer than that for patients with high ΔSP-D (MST, 159 days; 95% CI, 72–328 in low ΔSP-D [blue line] versus MST, 30 days; 95% CI, 3–33 in high ΔSP-D [black line], HR: 26.02, p = 0.001, by log-rank test)