Table 2.
Comparison of Baseline Variables Between Surgical and Non-Surgical Groups in Unmatched and Matched Data Sets
| Unmatched Data Set | Matched Data Set | |||||
|---|---|---|---|---|---|---|
| Surgery | No surgery | P | Surgery | No surgery | P | |
| Sample size, No. | 110 | 113 | — | 72 | 72 | — |
| Age, years, median (range) | 49 (26-71) | 52 (25-73) | .058 | 50 (26-71) | 51 (25-70) | .87 |
| Primary Breast Cancer | ||||||
| Stage at diagnosis | .25 | .39 | ||||
| 0-I | 19 (17) | 11 (10) | 10 (14) | 5 (7) | ||
| II-III | 41 (37) | 48 (42) | 27 (38) | 30 (42) | ||
| IV | 50 (46) | 54 (48) | 35 (49) | 37 (51) | ||
| Grade | .004 | .73 | ||||
| 1-2 | 51 (46) | 30 (27) | 24 (33) | 26 (36) | ||
| 3 | 59 (54) | 81 (72) | 48 (67) | 46 (64) | ||
| Unknown | 0 | 2 (2) | 0 | 0 | ||
| Estrogen receptor status positive | 73 (66) | 75 (66) | 1.00 | 45 (63) | 47 (65) | .73 |
| Progesterone receptor status positive | 46 (42) | 49 (43) | .82 | 31 (43) | 29 (40) | .74 |
| Human epidermal growth factor receptor 2 status positive | 40 (36) | 48 (42) | .35 | 27 (38) | 27 (38) | 1.00 |
| Primary tumor resected before BCLM diagnosis | 66 (60) | 64 (57) | .61 | 42 (58) | 39 (54) | .61 |
| Liver Metastases | ||||||
| Synchronous presentation | 52 (47) | 55 (49) | .89 | 37 (51) | 37 (51) | 1.00 |
| Median number by imaging (range) | 1 (1-14) | 2 (1-10) | .016 | 1 (1-14) | 2 (1-7) | .079 |
| Size of largest metastasis in cm by imaging, median (range) | 2.5 (0.9-14.0) | 2.5 (0.8-8.7) | .69 | 2.5 (0.9-14.0) | 2.5 (0.9-8.5) | .77 |
| Year of diagnosis | .34 | .97 | ||||
| 1997-2003 | 25 (23) | 27 (24) | 15 (21) | 16 (22) | ||
| 2004-2009 | 48 (44) | 39 (35) | 33 (46) | 33 (46) | ||
| 2010-2016 | 37 (34) | 47 (42) | 24 (33) | 23 (32) | ||
| Medical therapy for BCLM | ||||||
| Taxane and/or anthracycline based | 74 (67) | 66 (58) | .17 | 47 (65) | 44 (61) | .60 |
| Other cytotoxic regimen | 36 (33) | 47 (42) | 25 (35) | 28 (39) | ||
| Endocrine therapy | 16 (15) | 26 (23) | .11 | 10 (14) | 16 (22) | .19 |
| HER2-directed therapy | 34 (31) | 37 (33) | .77 | 23 (32) | 21 (29) | .72 |
| Best response to medical therapy | .24 | .71 | ||||
| Partial or complete | 81 (74) | 75 (66) | 54 (75) | 52 (72) | ||
| Stable or progressive disease | 29 (26) | 38 (34) | 18 (25) | 20 (28) | ||
Data are presented as No. (%) unless indicated otherwise