Table 1.
Patient characteristics in all cohorts
| Training cohort (n=130) |
Internal validation cohort (n=44) |
External validation cohort 1 (n=71) |
External validation cohort 2 (n=28) |
|||||||||
| Responders (n=44) |
Non-responders (n=86) | P value | Responders (n=21) |
Non-responders (n=23) | P value | Responders (n=36) |
Non-responders (n=35) | P value | Responders (n=12) |
Non-responders (n=16) | P value | |
| Age | 0.99 | 0.57 | 0.18 | 0.05 | ||||||||
| Median, IQR (years) | 58 (52–66) | 62 (48–66) | 60 (49–68) | 63 (50–69) | 57 (50–65) | 62 (54–67) | 54 (46–63) | 63 (57–67) | ||||
| Sex | 0.39 | 0.05 | 0.12 | 0.24 | ||||||||
| Male | 28 (64) | 48 (56) | 5 (24) | 11 (48) | 24 (67) | 29 (83) | 6 (50) | 12 (75) | ||||
| Female | 16 (36) | 38 (44) | 16 (76) | 12 (52) | 12 (33) | 6 (17) | 6 (50) | 4 (25) | ||||
| Location | 0.35 | 0.12 | 1.00 | |||||||||
| Cardia | 9 (20) | 24 (28) | 7 (33) | 8 (35) | 1.00 | 9 (25) | 6 (17) | 4 (33) | 4 (25) | |||
| Body | 8 (18) | 17 (20) | 3 (14) | 4 (17) | 8 (22) | 7 (20) | 3 (25) | 5 (31) | ||||
| Antrum | 25 (57) | 36 (42) | 10 (48) | 9 (39) | 19 (53) | 17 (49) | 5 (42) | 7 (44) | ||||
| Whole | 2 (5) | 9 (10) | 1 (5) | 2 (9) | 0 | 5 (14) | 0 | 0 | ||||
| Differentiation | 0.31 | 0.91 | 0.10 | 0.60 | ||||||||
| Well | 2 (5) | 3 (3) | 0 | 0 | 1 (3) | 1 (3) | 0 | 1 (6) | ||||
| Moderate | 9 (20) | 12 (14) | 3 (14) | 3 (13) | 9 (25) | 3 (9) | 0 | 1 (6) | ||||
| Poor or undifferentiation | 33 (75) | 71 (83) | 18 (86) | 20 (87) | 26 (72) | 31 (89) | 12 (100) | 14 (88) | ||||
| CEA | 0.15 | 0.39 | 0.53 | 1.00 | ||||||||
| Elevated | 16 (36) | 21 (24) | 10 (48) | 8 (35) | 7 (19) | 9 (26) | 5 (42) | 7 (44) | ||||
| Normal | 28 (64) | 65 (76) | 11 (52) | 15 (65) | 29 (81) | 26 (74) | 7 (58) | 9 (56) | ||||
| CA19-9 | 0.85 | 0.21 | 0.09 | 0.36 | ||||||||
| Elevated | 14 (32) | 26 (30) | 7 (33) | 12 (52) | 3 (8) | 8 (23) | 1 (8) | 4 (25) | ||||
| Normal | 30 (68) | 60 (70) | 14 (67) | 11 (48) | 33 (92) | 27 (77) | 11 (92) | 12 (75) | ||||
| PD-L1 expression (CPS) | 0.14 | 0.51 | 0.38 | 1.00 | ||||||||
| <1 | 7 (16) | 19 (22) | 3 (14) | 7 (30) | 9 (25) | 9 (26) | 3 (25) | 4 (25) | ||||
| 1–10 | 22 (50) | 51 (59) | 9 (43) | 8 (35) | 23 (64) | 18 (51) | 5 (42) | 7 (44) | ||||
| >10 | 15 (34) | 16 (19) | 9 (43) | 8 (35) | 4 (11) | 8 (23) | 4 (33) | 5 (31) | ||||
| Line of immune checkpoint inhibitor therapy | 0.15 | 0.40 | <0.01 | 1.00 | ||||||||
| 1 | 10 (23) | 30 (35) | 18 (86) | 18 (78) | 31 (86) | 13 (37) | 5 (42) | 7 (44) | ||||
| ≥2 | 34 (77) | 56 (65) | 3 (14) | 5 (22) | 5 (14) | 22 (63) | 7 (58) | 9 (56) | ||||
| Therapy regimen | 0.13 | 0.29 | 1.00 | 0.57 | ||||||||
| Anti-PD-(L)1 immune checkpoint inhibitor monotherapy | 3 (7) | 14 (16) | 18 (86) | 16 (70) | 2 (6) | 2 (6) | 8 (67) | 10 (63) | ||||
| Immune checkpoint inhibitor plus chemotherapy | 41 (93) | 72 (84) | 3 (14) | 7 (30) | 34 (94) | 33 (94) | 4 (33) | 6 (38) | ||||
Data are n (%), or median (IQR).
CA19-9, carbohydrate antigen 19-9; CEA, carcinoembryonic antigen; CPS, Combined Positive Score of PD-L1 expression; PD-L1, programmed death ligand 1.