Table 2. Invariant analysis of continuous variables.
| Characteristics | Occult malignant pleural disease | P value | |
|---|---|---|---|
| No (mean ± SD) | Yes (mean ± SD) | ||
| Tumor size (cm) | 3.2±4.9 | 3.0±1.7 | 0.704 |
| CEA (ng/mL) (n=1,723) | 10.7±67.2 | 31.8±74.6 | 0.003 |
| CA125 (U/mL) (n=1,228) | 19.8±56.4 | 37.7±68.7 | 0.012 |
| CA199 (U/mL) (n=1,246) | 52.2±481.1 | 94.2±321.4 | 0.484 |
| NSE (ng/mL) (n=1,700) | 15.0±38.8 | 13.9±6.6 | 0.779 |
| CYFRA21-1 (ng/mL) (n=1,696) | 4.9±40.3 | 3.9±4.3 | 0.825 |
| SCC (ng/mL) (n=1,686) | 1.2±3.0 | 1.1±3.6 | 0.992 |
CEA, carcinoembryonic antigen; CA125, carbohydrate antigen 125; CA199, carbohydrate antigen 199; NSE, neuron specific enolase; CYFRA21-1, cytokeratin 19 fragment 21-1; SCC, squamous cell carcinoma; SD, standard deviation.