Table 2.
The HRs and heterogeneity for direct comparisons
| Outcome | No. of studies | Events | Total | Events | Total | HR (95% CI) | P* | I 2, % |
|---|---|---|---|---|---|---|---|---|
| BCS+SLNB | BCS+SLNB+RT | |||||||
| OS | 5 | 1012 | 3596 | 919 | 3594 | 1.10 (1.02 to 1.18) | .01 | 0 |
| DFS | 4 | 1071 | 2931 | 955 | 2933 | 1.17 (0.90 to 1.52) | .25 | 55.3 |
| BCS+ALND | M+ALND | |||||||
| OS | 2 | 246 | 845 | 279 | 807 | 0.83 (0.67 to 1.02) | .08 | 52.7 |
| DFS | 3 | 215 | 787 | 155 | 865 | 1.03 (0.63 to 1.66) | .92 | 78.0 |
| BCS+ALND | BCS+ALND+RT | |||||||
| OS | 8 | 739 | 2584 | 699 | 2641 | 1.06 (0.98 to 1.14) | .18 | 0 |
| DFS | 6 | 236 | 1929 | 222 | 1983 | 1.07 (0.70 to 1.62) | .76 | 72.8 |
| BCS+ALND+RT | M+ALND+RT | |||||||
| OS | 2 | 309 | 536 | 278 | 508 | 0.95 (0.66 to 1.36) | .77 | 78.2 |
| DFS | 2 | 231 | 536 | 207 | 508 | 0.97 (0.67 to 1.39) | .85 | 63.5 |
| BCS+ALND+RT | BCS+SLNB+RT | |||||||
| OS | 5 | 118 | 1629 | 119 | 1654 | 0.99 (0.68 to 1.45) | .96 | 51.8 |
| DFS | 5 | 121 | 1434 | 118 | 1416 | 0.99 (0.78 to 1.26) | .99 | 0 |
| BCS+ALND+RT | BCS+SLNB+ART+RT | |||||||
| OS | 1 | 80 | 326 | 87 | 332 | 0.94 (0.72 to 1.22) | .62 | — |
| DFS | 1 | 116 | 326 | 115 | 332 | 1.03 (0.84 to 1.26) | .80 | — |
| BCS+SLBN+ART+RT | BCS+SLNB+RT | |||||||
| OS | 1 | 2 | 221 | 8 | 214 | 0.24 (0.05 to 1.13) | .07 | — |
| DFS | 1 | 3 | 221 | 8 | 214 | 0.36 (0.10 to 1.35) | .13 | — |
| BCS+ANS+RT | BCS+ALND+RT | |||||||
| OS | 1 | 27 | 234 | 42 | 232 | 0.87 (0.65 to 1.18) | .37 | — |
| DFS | 1 | 49 | 234 | 56 | 232 | 0.87 (0.62 to 1.22) | .41 | — |
| BCS+SLNB+IORT | BCS+SLNB+RT | |||||||
| OS | 3 | 77 | 1412 | 79 | 1335 | 0.94 (0.64 to 1.39) | .76 | 38.8 |
| DFS | 4 | 73 | 1511 | 84 | 1420 | 0.83 (0.61 to 1.13) | .24 | 1.2 |
| BCS+SLNB+RT | M | |||||||
| OS | 4 | 854 | 2435 | 855 | 2454 | 1.01 (0.84 to 1.22) | .91 | 61.3 |
| DFS | 3 | 999 | 2347 | 1018 | 2363 | 0.94 (0.78 to 1.15) | .55 | 55.5 |
| BCS+SLNB | M | |||||||
| OS | 1 | 700 | 1853 | 642 | 1775 | 1.05 (0.96 to 1.14) | .32 | — |
| DFS | 2 | 1018 | 2278 | 853 | 1817 | 1.09 (1.02 to 1.16) | .01 | 0 |
| M+RT | M | |||||||
| OS | 1 | 159 | 646 | 86 | 365 | 1.05 (0.83 to 1.31) | .71 | — |
| DFS | 1 | 238 | 646 | 107 | 365 | 1.26 (1.04 to 1.52) | .02 | — |
| M+ALND | BCS+ALND+RT | |||||||
| OS | 1 | 46 | 116 | 52 | 121 | 0.92 (0.68 to 1.25) | .60 | — |
| DFS | 1 | 27 | 116 | 30 | 121 | 0.94 (0.60 to 1.48) | .79 | — |
| BCS+ALND | BCS+SLNB | |||||||
| DFS | 1 | 63 | 420 | 52 | 425 | 1.23 (0.87 to 1.73) | .24 | — |
| M | BCS+ALND | |||||||
| DFS | 1 | 3 | 42 | 63 | 420 | 0.48 (0.16 to 1.45) | .13 | — |
| M+ALND | M | |||||||
| DFS | 1 | 6 | 44 | 3 | 42 | 1.91 (0.51 to 7.15) | .34 | — |
| M+ALND | BCS+SLNB | |||||||
| DFS | 1 | 6 | 44 | 52 | 425 | 1.12 (0.51 to 2.45) | .79 | — |
The HRs and 95% CIs were used for pooling effect sizes using the DerSimonian-Laird random-effects model. I2 quantifies the effect of heterogeneity in the studies’ results with values greater than 50% indicative of large between-study heterogeneity, values of 25%–50% indicative of modest heterogeneity, and values less than 25% indicative of low heterogeneity. All statistical tests were two-sided. BCS+ALND = breast-conserving surgery+axillary lymph node dissection; BCS+ALND+RT = breast-conserving surgery+axillary lymph node dissection+radiotherapy; BCS+ANS+RT = breast-conserving surgery+axillary node sample+radiotherapy; BCS+SLNB = breast-conserving surgery+sentinel lymph node biopsy; BCS+SLNB+ART+RT = breast-conserving surgery+sentinel lymph node biopsy+axillary radiotherapy+radiotherapy; BCS+SLNB+IORT = breast-conserving surgery+sentinel lymph node biopsy+intraoperative radiotherapy. BCS+SLNB+RT = breast-conserving surgery+sentinel lymph node biopsy+radiotherapy; CI = confidence interval; DFS = disease-free survival; HR = hazard ratio; M = mastectomy; M+ALND = mastectomy+axillary lymph node dissection; M+ALND+RT = mastectomy+axillary lymph node dissection+radiotherapy; M+RT = mastectomy+radiotherapy; OS = overall survival.