Table 2.
Characteristics at the time of starting pembrolizumab.
| High PD-L1 (n = 9) | Low PD-L1 (n = 17) | Total (n = 26) | P-value | |
|---|---|---|---|---|
| Age, median (range) | 70 (59–74) | 61 (41–86) | 67 (41–86) | 0.372 |
| Female | 5 (56%) | 8 (47%) | 13 (50%) | 0.680 |
| Location of tumor* | 0.427 | |||
| Intrahepatic | 3 (33%) | 7 (41%) | 10 (38%) | |
| Hilar (Klatskin) | 0 (0%) | 3 (18%) | 3 (12%) | |
| Extrahepatic† | 2 (22%) | 3 (18%) | 5 (19%) | |
| Gallbladder | 4 (44%) | 3 (18%) | 7 (27%) | |
| AoV | 0 (0%) | 1 (6%) | 1 (4%) | |
| Stage | 0.960 | |||
| Localized | 1 (11%) | 2 (12%) | 3 (12%) | |
| Metastatic | 8 (89%) | 15 (88%) | 23 (88%) | |
| Number of metastatic organ | 0.272 | |||
| 0 | 1 (11%) | 2 (12%) | 3 (12%) | |
| 1 | 0 (0%) | 5 (29%) | 5 (19%) | |
| 2 | 6 (67%) | 6 (35%) | 12 (46%) | |
| ≥ 3 | 2 (22%) | 4 (24%) | 6 (23%) | |
| ECOG performance score | 0.648 | |||
| 0–1 | 5 (56%) | 11 (65%) | 16 (62%) | |
| ≥ 2 | 4 (44%) | 6 (35%) | 10 (38%) | |
| Tumor marker, median (IQR) | ||||
| CEA | 5.0 (1.8–13.2) | 3.5 (1.9–19.9) | 5.0 (1.9–23.7) | 0.572 |
| CA 19–9 | 141 (29–1900) | 260 (50–950) | 220 (29–1,360) | 0.335 |
| Level of PD-L1 | ||||
| median % (range %) | 80 (60–95) | 2 (1–30) | 5 (1–95) | < 0.001 |
| MSI status | 0.548 | |||
| MSI-high | 0 (0%) | 1 (6%) | 1 (4%) | |
| MSS or MSI-low | 8 (89%)§ | 16 (94%) | 24 (92%)§ | |
PD-L1, programmed cell death ligand 1; AoV, Ampulla of Vater; ECOG, Eastern Cooperative Oncology Group; IQR, interquartile range; MSI, microsatellite instability; MSS, microsatellite stable.
*Epicenter of the tumor, †Extrahepatic bile duct cancer excluding hilar bile duct cancer, §The result of one patient was not available.