Table 1.
Patient characteristics
| Characteristic | Overall* | BED < 96 Gy* | BED ≥ 96 Gy* | P value† |
|---|---|---|---|---|
| No. of patients/lesions | 90/122 | 30/36 | 60/86 | |
| Median age at diagnosis of primary in years (range) | 53.2 (22.6-85.0) | 54.2 (37.5-85.0) | 52.9 (22.6-78.7) | .5 |
| Median time from diagnosis of primary to liver metastasis in months (range)‡ | 0.0 (0-168.0) | 11.0 (0-83.0) | 0.0 (0-168.0) | <.001 |
| Median time from diagnosis of liver metastasis to RT in months (range) | 35.1 (0-127.2) | 35.1 (3.8-127.2) | 33.4 (0-109.2) | .2 |
| Median age at RT in years (range) | 57.1 (26.1-88.8) | 58.6 (42.1-88.8) | 57.1 (26.1-80.3) | .3 |
| Gender | .5 | |||
| Male | 58 (64.4) | 18 (60.0) | 40 (66.7) | |
| Female | 32 (35.6) | 12 (40.0) | 20 (33.3) | |
| Stage at initial diagnosis | <.001 | |||
| M0 | 30 (33.3) | 18 (60.0) | 12 (20.3) | |
| M1 | 59 (65.6) | 12 (40.0) | 47 (78.3) | |
| KRAS mutation status | .6 | |||
| Wild type | 42 (46.7) | 10 (33.3) | 32 (53.3) | |
| Mutated | 27 (30.0) | 5 (16.7) | 22 (36.7) | |
| Unknown | 21 (23.3) | 15 (50.0) | 6 (10.0) | |
| Median CEA at RT (range)§ | 10.6 (0.9-7724.7) | 17.1 (1.2-7724.7) | 9.6 (0.9-1754.0) | .11 |
| Number of liver lesions at time of RT | .2 | |||
| 1 lesion | 54 (60.0) | 21 (70.0) | 33 (55.0) | |
| ≥2 lesions | 36 (40.0) | 9 (30.0) | 27 (45.0) | |
| Extrahepatic metastatic sites at RT | .3 | |||
| No | 34 (37.8) | 9 (30.0) | 25 (41.7) | |
| Yes | 56 (62.2) | 21 (70.0) | 35 (58.3) | |
| Median lesion size in cm (range) | 3.47 (0.73-11.8) | 4.14 (1.26-11.8) | 2.94 (0.73-9.41) | .006 |
| Median BED in Gy (range) | 97.9 (43.2-187.5) | 66.0 (43.2-85.5) | 100.0 (96.0-187.5) | |
| Prior therapies, N (%) | ||||
| Systemic therapy | 87 (96.7) | 30 (100.0) | 57 (95.0) | .5 |
| Lines of chemotherapy | .2 | |||
| 0 | 1 (1.1%) | 0 (0%) | 1 (1.7%) | |
| 1 | 14 (15.6) | 3 (10.0) | 11 (18.3) | |
| 2 | 26 (28.9) | 8 (26.7) | 18 (30.0) | |
| 3 | 21 (23.3) | 7 (23.3) | 14 (23.3) | |
| 4 | 18 (20.0) | 5 (16.7) | 13 (21.7) | |
| ≥5 | 10 (11.1) | 7 (23.3) | 3 (5.0) | |
| Any liver-directed therapy | 73 (81%) | 24 (80%) | 49 (82%) | .8 |
| Hepatectomy | 63 (70.0) | 20 (66.7) | 43 (71.7) | .6 |
| HAI pump | 56 (62.2) | 18 (60.0) | 38 (63.3) | .8 |
| RFA | 31 (34.4) | 7 (23.3) | 24 (40.0) | .12 |
| Y90 | 5 (5.6) | 0 (0) | 5 (8.3) | .2 |
| Embolization | 8 (8.9) | 2 (6.7) | 6 (10.0) | .7 |
Abbreviations: BED = biologically effective dose; CEA = carcinoembryonic antigen; HAI = hepatic artery infusion; RFA = radiofrequency ablation; RT = radiation therapy.
⁎
Median (range); n (%).
†
Wilcoxon rank sum test; Pearson's χ2 test; Fisher's exact test.
‡
Time from diagnosis of primary to liver metastasis was reported as simultaneous if occurred within 4 weeks of each other.
§
CEA at RT was log transformed to stabilize regression results.