Table 1.
Clinical characteristics of patients in the deferred RT and upfront RT groups.
| Characteristic | Total | Deferred RT (n = 94) | Upfront RT (n = 104) | p-value |
|---|---|---|---|---|
| N (%) | N (%) | |||
| Year of treatment | <0.001 | |||
| 2010–2015 | 94 (47.5) | 23 (24.5) | 71 (68.3) | |
| 2016–2020 | 104 (52.5) | 71 (75.5) | 33 (31.7) | |
| Age at BM (median, years) | 54 | 53 | 54 | 0.792 |
| Sex | 0.709 | |||
| Male | 87 (43.9) | 40 (42.6) | 47 (45.2) | |
| Female | 111 (56.1) | 54 (57.4) | 57 (54.8) | |
| KPS | 0.145 | |||
| <80 | 31 (15.7) | 11 (11.7) | 20 (19.2) | |
| ≥80 | 167 (84.3) | 83 (88.3) | 84 (80.8) | |
| Ds-GPA | 0.308 | |||
| 0–2 | 119 (60.1) | 60 (63.8) | 59 (56.7) | |
| 2.5–4.0 | 79 (39.9) | 34 (36.2) | 45 (43.3) | |
| Symptomatic BM | <0.001 | |||
| Yes | 80 (40.4) | 21 (22.3) | 59 (56.7) | |
| No | 118 (59.6) | 73 (77.7) | 45 (43.3) | |
| BM number | 0.238 | |||
| 1 | 62 (31.3) | 30 (31.9) | 32 (30.8) | |
| 2–4 | 71 (35.9) | 26 (27.7) | 45 (43.3) | |
| ≥5 | 65 (32.8) | 38 (40.4) | 27 (26.0) | |
| BM volume | 0.543 | |||
| <5 cc | 122 (61.6) | 60 (63.8) | 62 (59.6) | |
| ≥5 cc | 76 (38.4) | 34 (36.2) | 42 (40.4) | |
| Extracranial disease | 0.268 | |||
| Primary/regional site | 43 (21.7) | 17 (18.1) | 26 (25.0) | |
| Metastases | 26 (13.1) | 20 (21.3) | 6 (5.8) | |
| Both | 90 (45.5) | 43 (45.7) | 47 (45.2) | |
| None | 39 (19.7) | 14 (14.9) | 25 (24.0) | |
| Extracranial disease status | 0.045 | |||
| Progressed | 68 (34.3) | 38 (40.4) | 30 (28.8) | |
| Controlled | 91 (46.0) | 42 (44.7) | 49 (47.1) | |
| None | 39 (19.7) | 14 (14.9) | 25 (24.0) | |
| BM at diagnosis | 0.013 | |||
| Synchronous | 59 (29.8) | 20 (21.3) | 39 (37.5) | |
| Metachronous | 139 (70.2) | 74 (78.7) | 65 (62.5) | |
| Time to BM | 0.840 | |||
| <36 m | 176 (88.9) | 84 (89.4) | 92 (88.5) | |
| ≥36 m | 22 (11.1) | 10 (10.6) | 12 (11.5) | |
| TKI before BM | <0.001 | |||
| Yes | 58 (29.3) | 39 (41.5) | 19 (18.3) | |
| No | 140 (70.7) | 55 (58.5) | 85 (81.7) | |
| Gene-mutation type | ||||
| EGFR mutation | 159 (80.3) | 72 (76.6) | 87 (83.7) | 0.212 |
| Recorded mutation | 123 (62.1) | 69 (73.4) | 54 (51.9) | |
| Uncertain | 36 (18.2) | 3 (3.2) | 33 (31.7) | |
| ALK rearrangements | 32 (16.2) | 20 (21.3) | 12 (11.5) | 0.063 |
| Other mutations | 7 (3.5) | 2 (2.1) | 5 (4.8) | 0.308 |
| RET fusion | 3 (1.5) | 1 (1.1) | 2 (1.9) | |
| C-MET mutations | 2 (1.0) | 0 (0.0) | 2 (1.9) | |
| ROS-1 rearrangements | 1 (0.5) | 0 (0.0) | 1 (1.0) |
N, number; BM, brain metastases; KPS, Karnofsky Performance Score; Ds-GPA, disease specific-graded prognostic assessment; TKI, tyrosine kinase inhibitor; RT, radiation therapy; EGFR, epidermal growth factor receptor; ALK, anaplastic lymphoma kinase; C-MET, cellular–mesenchymal epithelial transition factor; ROS-1, c-Ros Oncogene 1.