Table 1.
Patient, tumor, and treatment characteristics overall and in patients with and without prior hepatic resection*
| Characteristic | Total (n=82) | Prior hepatic resection (n=49) | No prior hepatic resection (n=33) | P value† |
|---|---|---|---|---|
| Sex, M: F | 54: 28 | 32: 17 | 22: 11 | 0.899 |
| Age at CLM ablation, median (range), y | 59 (28–92) | 56 (28–80) | 62 (40–92) | 0.017‡ |
| Primary tumor | ||||
| Location, colon: rectum | 68: 14 | 43: 6 | 25: 8 | 0.157 |
| Midgut origin: hindgut origin | 16: 66 | 7: 42 | 9: 24 | 0.146 |
| Lymph node metastases | 58 (71) | 36 (73) | 22 (67) | 0.507 |
| Time between primary cancer diagnosis and CLM discovery, median (range), months | 18 (0–295) | 19 (0–199) | 15 (0–295) | 0.166‡ |
| Time between last hepatic resection and ablation, median (range), months | - | 13 (0.9–125) | - | - |
| Pre-ablation chemotherapy | 54 (66) | 28 (57) | 26 (79) | 0.043 |
| ≤6 cycles | 24 (44) | 16 (57) | 8 (31) | 0.051 |
| ≥2 regimens | 13 (24) | 3 (11) | 10 (38) | 0.017 |
| Fluorouracil-based chemotherapy regimen | ||||
| Oxaliplatin | 30 (56) | 14 (50) | 16 (62) | 0.394 |
| Irinotecan | 25 (46) | 14 (50) | 11 (42) | 0.571 |
| Use of bevacizumab | 33 (61) | 15 (54) | 18 (69) | 0.238 |
| Use of anti-EGFR agent | 8 (15) | 5 (18) | 3 (12) | 0.514 |
| Time between last chemotherapy and ablation, median (range), days | 34 (6–3674) | 32 (6–875) | 38 (6–3674) | 0.603‡ |
| Time between CLM discovery and ablation, median (range), days | 139 (4–1397) | 102 (4–828) | 266 (29–1397) | <0.001‡ |
| CEA level at ablation, median (range), ng/mL | 4.3 (0.6–328) | 3.3 (0.6–186) | 5.7 (1.2–328) | 0.085‡ |
| RAS status | ||||
| Wild-type: mutant | 53: 29 | 35: 14 | 18: 15 | 0.117 |
| Clinical risk score¶ | ||||
| 0/1: ≥2 | 53: 29 | 33: 16 | 20: 13 | 0.531 |
| Ablation modality | ||||
| RFA: microwave: cryoablation | 45: 30: 7 | 30: 15: 4 | 15: 15: 3 | 0.350 |
| No. of ablation sessions | ||||
| 1: ≥2 | 63: 19 | 36: 13 | 27: 6 | 0.380 |
| Minimal radiographic ablation margin | ||||
| <5 mm: 5–10 mm: >10 mm | 30: 26: 26 | 16: 15: 18 | 14: 11: 8 | 0.465 |
| Ablated lesion adjacent to major vessel(s)© | 20 (24) | 11 (22) | 9 (27) | 0.618 |
| Liver metastases | ||||
| Synchronous: metachronous | 30: 52 | 14: 35 | 16: 17 | 0.066 |
| Maximum CLM diameter at ablation, median (range), cm | 1.7 (0.6–5.0) | 1.4 (0.6–4.5) | 2.1 (1.0–5.0) | 0.001‡ |
| Tumor number, solitary: multiple | 70: 12 | 40: 9 | 30: 3 | 0.232 |
| Subcapsular lesion | 43 (52) | 24 (49) | 19 (58) | 0.445 |
| Concomitant extrahepatic disease | 19 (23) | 10 (20) | 9 (27) | 0.470 |
| Post-ablation chemotherapy | 43 (52) | 23 (47) | 20 (61) | 0.224 |
| Local tumor progression | 15 (18) | 3 (6.1) | 12 (36) | <0.001 |
Values in table are number of patients (percentage) unless indicated otherwise.
χ2 test unless indicated otherwise.
Wilcoxon rank-sum test.
Clinical risk score was determined by assigning 1 point for each of the following: disease-free interval from detection of primary tumor to detection of liver metastasis <12 months, >1 liver tumor, largest hepatic metastasis > cm, carcinoembryonic antigen level >200 ng/mL, and the presence of extrahepatic disease [Fong et al, Ann Surg, 1999].
A major vessel meant a vessel >3 mm in diameter.
CLM, colorectal liver metastases; EGFR, epidermal growth factor receptor; CEA, carcinoembryonic antigen; RFA, radiofrequency ablation.