Prognostic analysis of 
PD, ≤118.8)LMR(<4.59
REGRESSION
As displayed in Table Cox regression analysis of clinical characteristics in connection with PFS in the training cohort of SCLC.CAR(>0.51 vs. ≤0.51)NLR(>1.28 vs. ≤1.28)LDH (U/L)(>250 vs. ≤250)NSE (ng/mL)(>16.3 vs. ≤16.3)Hyponatremia(yes vs. no)The best efficacy to first‐line chemotherapy(SD + PD vs. CR + PR)2.075 (1.601–2.690)<0.0012.045 (1.569–2.665)<0.001Stage(ES‐SCLC vs. LS‐SCLC)AGR(<1.36 vs. ≥1.36)Hemoglobin (g/L)(<120 vs. ≥120)Age(>65 vs. ≤65)Sex(male vs. female)Smoking history(Yes vs. No)RDW(<14.3 vs. ≥14.3)PLR(>118.8 vs. ≤118.8)LMR(<4.59 vs. ≥4.59)PNI(<397.0 vs. ≥397.0)CEA (ng/mL)(>4.3 vs. ≤4.3)LCR(<0.39 vs. ≥0.39)