Table 1.
Baseline characteristics and odds ratios for likelihood of frameless SRS
| Characteristic | All patients (%) (n = 95) |
Framed cases (%) (n = 39) |
Frameless cases (%) (n = 56) |
Odds ratio (95% CI) |
P value |
|---|---|---|---|---|---|
| Sex | |||||
| Male | 41 (43) | 19 (49) | 22 (39) | 1 | |
| Female | 54 (57) | 20 (51) | 34 (61) | 1.47 (0.64-3.35) | .36 |
| Age, y | |||||
| ≤61 | 48 (51) | 8 (21) | 40 (71) | 1 | |
| >61 | 47 (50) | 31 (79) | 16 (29) | 1.78 (0.78-4.08) | .17 |
| Primary malignancy | |||||
| Lung (NSCLC/SCLC/LCNEC) | 50 (53) | 18 (46) | 32 (57) | 1 | |
| Breast | 21 (22) | 9 (23) | 12 (21) | 0.75 (0.27-2.12) | .59 |
| Melanoma | 14 (15) | 7 (18) | 7 (13) | 0.56 (0.17-1.86) | .35 |
| GI (anal/colon/rectal) | 4 (4) | 1 (1) | 3 (5) | 1.69 (0.16-17.44) | .66 |
| Other* | 6 (6) | 4 (12) | 2 (4) | 0.28 (0.05-1.69) | .17 |
| KPS | |||||
| 50 | 2 (2) | 2 (5) | 0 (0) | 1 | |
| 60 | 3 (3) | 1 (3) | 2 (4) | 8.33 (0.22-320.40) | .25 |
| 70 | 8 (8) | 2 (5) | 6 (11) | 13.00 (0.45-377.49) | .14 |
| 80 | 48 (51) | 17 (44) | 31 (55) | 9.00 (0.41-198.22) | .16 |
| 90 | 31 (33) | 15 (38) | 16 (29) | 5.32 (0.24-119.88) | .29 |
| 100 | 3 (3) | 2 (5) | 1 (1) | 3.00 (0.08-115.35) | .56 |
| GPA score | |||||
| 0-1.0 | 34 (36) | 14 (36) | 23 (41) | 1 | |
| 1.5-2.5 | 49 (52) | 19 (49) | 29 (52) | 1.02 (0.42-2.47) | .97 |
| 3.0 | 5 (5) | 3 (8) | 2 (4) | 0.47 (0.07-3.17) | .44 |
| 3.5-4.0 | 7 (7) | 2 (7) | 5 (3) | 1.75 (0.30-10.34) | .54 |
| Extracranial disease | |||||
| No | 32 (34) | 16 (41) | 16 (29) | 1 | |
| Yes | 63 (66) | 23 (59) | 40 (71) | 1.74 (0.73-4.12) | .21 |
| Past WBRT | |||||
| No | 75 (79) | 29 (74) | 46 (82) | 1 | |
| Yes | 20 (21) | 10 (26) | 10 (18) | 0.63 (0.23-1.70) | .36 |
| Surgery to metastasis | |||||
| No | 87 (92) | 35 (90) | 52 (93) | 1 | |
| Yes | 8 (8) | 4 (10) | 4 (7) | 0.67 (0.16-2.87) | .59 |
| Total no. of metastases | |||||
| 1-5 | 74 (77) | 24 (62) | 50 (89) | 1 | |
| 6-10 | 12 (13) | 8 (21) | 4 (7) | 0.24 (0.07-0.88) | .03 |
| 11-15 | 5 (5) | 4 (12) | 1 (2) | 0.12 (0.01-1.13) | .06 |
| 16-20 | 4 (5) | 3 (5) | 1 (2) | 0.16 (0.02-1.62) | .12 |
| Total treatment volume (mL) | |||||
| 0.0048-0.17 | 24 (25) | 6 (15) | 18 (32) | 1 | |
| 0.17-0.68 | 24 (25) | 9 (23) | 15 (27) | 0.63 (0.18-2.16) | .46 |
| 0.69-1.65 | 23 (25) | 9 (23) | 14 (25) | 0.55 (0.16-1.92) | .35 |
| >1.65 | 24 (25) | 15 (38) | 9 (16) | 0.21 (0.06-0.74) | .01 |
| Date of treatment | |||||
| May 2019-Dececember 2019 | 32 (34) | 30 (77) | 2 (3) | 1 | |
| January 2020-June 2020 | 27 (28) | 6 (15) | 21 (38) | 52.50 (9.64-285.87) | <.0001 |
| July 2020-Jan 2021 | 36 (38) | 3 (7) | 33 (59) | 165.00 (25.78-1055.99) | <.0001 |
Abbreviations: CI = confidence interval; GI = gastrointestinal; GPA = Graded Prognostic Assessment; KPS = Karnofsky Performance Status; LCNEC = large cell neuroendocrine carcinoma; NSCLC = non small cell lung cancer; SCLC = small cell lung cancer; SRS = stereotactic radiosurgery; WBRT = whole brain radiation.