Table 1 Baseline characteristics of the unmatched and matched groups
Characteristic | Before Propensity Score Matching | After Propensity Score Matching | ||||
|---|---|---|---|---|---|---|
Control group | Osimertinib group | p value | Control group | Osimertinib group | p value | |
NO. of patients | 188 | 116 | Â | 112 | 112 | Â |
Median age years (range) | 61 (25–87) | 60 (33–83) | 0.597 | 58(32–87) | 60 (33–83) | 0.088 |
Sex | Â | Â | 0.171 | Â | Â | 0.499 |
 Female | 100 (53.19%) | 71 (61.21%) |  | 62 (55.36%) | 67 (59.82%) |  |
 Male | 88 (46.81%) | 45 (38.79%) |  | 50 (44.64%) | 45 (40.18%) |  |
Smoking status | Â | Â | 0.182 | Â | Â | 0.293 |
 Never | 131 (69.68%) | 89 (76.72%) |  | 78 (69.64%) | 85 (75.89%) |  |
 Former or current | 57 (30.32%) | 27 (23.28%) |  | 34 (30.36%) | 27 (24.11%) |  |
Histological type | Â | Â | 0.62 | Â | Â | 0.714 |
 Adenocarcinoma | 178 (94.68%) | 109 (93.97%) |  | 103 (91.96%) | 105 (93.75%) |  |
 Adenosquamous carcinoma | 4 (2.13%) | 3 (2.59%) |  | 4 (3.57%) | 3 (2.68%) |  |
 Not otherwise specified | 4 (2.13%) | 1 (0.86%) |  | 3 (2.68%) | 1 (0.89%) |  |
 Squamous carcinoma | 2 (1.06%) | 3 (2.59%) |  | 2 (1.79%) | 3 (2.68%) |  |
EGFR mutations | Â | Â | 0.208 | Â | Â | 0.458 |
 Exon19 deletion | 96 (51.06%) | 71 (61.21%) |  | 60 (53.57%) | 69 (61.61%) |  |
 L858R mutation | 84 (44.68%) | 42 (36.21%) |  | 48 (42.86%) | 40 (35.71%) |  |
 Others | 8 (4.26%) | 3 (2.59%) |  | 4 (3.57%) | 3 (2.68%) |  |
T | Â | Â | 0.363 | Â | Â | 0.777 |
 0 | 13 (6.91%) | 10 (8.62%) |  | 7 (6.25%) | 10 (8.93%) |  |
 1 | 44 (23.40%) | 18 (15.52%) |  | 16 (14.29%) | 18 (16.07%) |  |
 2 | 85 (45.21%) | 63 (54.31%) |  | 59 (52.68%) | 60 (53.57%) |  |
 3 | 22 (11.70%) | 10 (8.62%) |  | 14 (12.50%) | 9 (8.04%) |  |
 4 | 24 (12.77%) | 15 (12.93%) |  | 16 (14.29%) | 15 (13.39%) |  |
N | Â | Â | 0.408 | Â | Â | 0.337 |
 0 | 42 (22.34%) | 30 (25.86%) |  | 25 (22.32%) | 30 (26.79%) |  |
 1 | 9 (4.79%) | 10 (8.62%) |  | 7 (6.25%) | 10 (8.93%) |  |
 2 | 114 (60.64%) | 61 (52.59%) |  | 71 (63.39%) | 58 (51.79%) |  |
 3 | 23 (12.23%) | 15 (12.93%) |  | 9 (8.04%) | 14 (12.50%) |  |
M | Â | Â | 0.63 | Â | Â | 0.704 |
 1a | 32 (17.02%) | 15 (12.93%) |  | 18 (16.07%) | 14 (12.50%) |  |
 1b | 12 (6.38%) | 8 (6.90%) |  | 9 (8.04%) | 8 (7.14%) |  |
 1c | 144 (76.60%) | 93 (80.17%) |  | 85 (75.89%) | 90 (80.36%) |  |
Clinical stage | Â | Â | 0.601 | Â | Â | 0.485 |
 IVa | 32 (17.02%) | 15 (12.93%) |  | 20 (17.86%) | 14 (12.50%) |  |
 IVb | 135 (71.81%) | 86 (74.14%) |  | 80 (71.43%) | 83 (74.11%) |  |
 Recurrence | 21 (11.17%) | 15 (12.93%) |  | 12 (10.71%) | 15 (13.39%) |  |
Brain metastasis | Â | Â | 0.224 | Â | Â | 0.414 |
 No | 105 (55.85%) | 73 (62.93%) |  | 64 (57.14%) | 70 (62.50%) |  |
 Yes | 83 (44.15%) | 43 (37.07%) |  | 48 (42.86%) | 42 (37.50%) |  |
Bone metastasis | Â | Â | 0.718 | Â | Â | 0.789 |
 No | 90 (47.87%) | 58 (50.00%) |  | 59 (52.68%) | 57 (50.89%) |  |
 Yes | 98 (52.13%) | 58 (50.00%) |  | 53 (47.32%) | 55 (49.11%) |  |
Liver metastasis | Â | Â | 0.824 | Â | Â | 1 |
 No | 162 (86.17%) | 101 (87.07%) |  | 98 (87.50%) | 98 (87.50%) |  |
 Yes | 26 (13.83%) | 15 (12.93%) |  | 14 (12.50%) | 14 (12.50%) |  |
Adrenal metastasis | Â | Â | 0.349 | Â | Â | 0.299 |
 No | 173 (92.02%) | 110 (94.83%) |  | 102 (91.07%) | 106 (94.64%) |  |
 Yes | 15 (7.98%) | 6 (5.17%) |  | 10 (8.93%) | 6 (5.36%) |  |
Metastatic status | Â | Â | 0.428 | Â | Â | 0.277 |
 Oligometastasis | 114 (60.64%) | 65 (56.03%) |  | 70 (62.50%) | 62 (55.36%) |  |
 Polymetastasis | 74 (39.36%) | 51 (43.97%) |  | 42 (37.50%) | 50 (44.64%) |  |
First-line EGFR-TKIs |  |  | < 0.001* |  |  | < 0.001* |
 Gefitnib | 129 (68.62%) | 55 (47.41%) |  | 74 (66.07%) | 54 (48.21%) |  |
 Erlotinib | 14 (7.45%) | 12 (10.34%) |  | 13 (11.61%) | 12 (10.71%) |  |
 Osimertinib | 0 (0.00%) | 27 (23.28%) |  | 0 (0.00%) | 27 (24.11%) |  |
 Icotinib | 35 (18.62%) | 20 (17.24%) |  | 21 (18.75%) | 18 (16.07%) |  |
 Afatinib | 10 (5.32%) | 2 (1.72%) |  | 4 (3.57%) | 1 (0.89%) |  |
T790M |  |  | < 0.001* |  |  | < 0.001* |
 No or unknow | 167 (88.8%) | 31 (26.7%) |  | 100 (89.3%) | 29 (25.9%) |  |
 Yes | 21 (11.2%) | 85 (73.3%) |  | 12 (10.7%) | 83 (74.1%) |  |
Chemotherapy | Â | Â | 0.033* | Â | Â | 0.109 |
 No | 122 (64.89%) | 61 (52.59%) |  | 49 (43.75%) | 61 (54.46%) |  |
 Yes | 66 (35.11%) | 55 (47.41%) |  | 63 (56.25%) | 51 (45.54%) |  |
Antiangiogenic therapy | Â | Â | 0.022* | Â | Â | 0.081 |
 No | 140 (74.47%) | 72 (62.07%) |  | 84 (75.00%) | 72 (64.29%) |  |
 Yes | 48 (25.53%) | 44 (37.93%) |  | 28 (25.00%) | 40 (35.71%) |  |
Immunotherapy | Â | Â | 0.347 | Â | Â | 0.061 |
 No | 177 (94.15%) | 112 (96.55%) |  | 101 (90.18%) | 108 (96.43%) |  |
 Yes | 11 (5.85%) | 4 (3.45%) |  | 11 (9.82%) | 4 (3.57%) |  |
Chest radiotherapy | Â | Â | 0.186 | Â | Â | 0.088 |
 No | 140 (74.47%) | 94 (81.03%) |  | 79 (70.54%) | 90 (80.36%) |  |
 Yes | 48 (25.53%) | 22 (18.97%) |  | 33 (29.46%) | 22 (19.64%) |  |
WBRT | Â | Â | 0.425 | Â | Â | 0.068 |
 No | 128 (68.09%) | 84 (72.41%) |  | 68 (60.71%) | 81 (72.32%) |  |
 Yes | 60 (31.91%) | 32 (27.59%) |  | 44 (39.29%) | 31 (27.68%) |  |
Number of lines of osimertinib therapy | Â | Â | 1 | Â | Â | 1 |
 First-line | 0 (%) | 27 (23.28%) |  | 0 (%) | 27 (24.11%) |  |
 Second-line | 0 (%) | 89 (76.72%) |  | 0 (%) | 85 (75.89%) |  |
Median FU (95% CI) | 18.3 (16.3–19.6) | 24.2 (21.2–26.5) | < 0.001* | 23.5 (19.3–24.0) | 25.5 (21.4–26.9) | 0.087 |