Table 1.
Baseline characteristics of the patients and controls
| SCLC a | Control | P value | |
|---|---|---|---|
| Total (n) | 250 | 250 | – |
| Age (n) | 64.5 ± 5.8 | 65.0 ± 5.8 | 0.381 |
| Gender (n) | |||
| Female | 53 | 67 | 0.143 |
| Male | 197 | 183 | |
| Smoking history (n) | |||
| Non-smoker | 107 | 135 | 0.012 |
| Smoker | 143 | 115 | |
| Performance status | |||
| 0–1 | 218 | – | – |
| 2 | 32 | – | – |
| Tumor grade (n) | |||
| High-middle | 193 | – | – |
| Low | 57 | – | – |
| Tumor stage (n) | |||
| LDa | 143 | – | – |
| EDa | 107 | – | – |
| EGFR (n)a | |||
| Negative | 202 | – | – |
| Positive | 48 | – | – |
| KRAS (n)a | |||
| Negative | 234 | – | – |
| Positive | 16 | – | – |
| Serum PD-L1 (ng/ml)a | 7.0 ± 3.0 | 1.2 ± 0.6 | <0.001 |
aSCLC Small cell lung cancer, LD Limited disease, ED Extensive disease, EGFR Epidermal growth factor receptor, KRAS Kirsten rat sarcoma viral oncogene, PD-L1 Programmed death ligand 1