Table 3.
Stratified Analysis and Heterogeneity Analysis of Relative Risks of Cardiac Death and Coronary Heart Disease in Radiotherapy Versus No Radiotherapy
| Factors Stratified | Coronary Heart Disease | Cardiac Mortality | ||||||
|---|---|---|---|---|---|---|---|---|
| Patients | Events | RR (95%CI) | P Valuea | Patients | Events | RR (95%CI) | P Valuea | |
| All studies | 155 236 | 10 640 | 1.30 (1.13‐1.49) | 137 074 | 5367 | 1.38 (1.18‐1.62) | ||
| Types of studies | ||||||||
| Observational studies | 149 104 | 10 490 | 1.26 (1.11‐1.44) | 0.31 | 98 245 | 3948 | 1.33 (1.01‐1.75) | 0.74 |
| RCT | 6132 | 150 | 2.63 (1.05‐6.58) | 38 829 | 1383 | 1.43 (1.17‐1.75) | ||
| Location | ||||||||
| Europe | 106 017 | 6142 | 1.29 (1.13‐1.17) | 0.02 | 113 719 | 4553 | 1.53 (1.31‐1.79) | 0.01 |
| North America | 866 | 142 | 2.78 (1.20‐6.40) | 3180 | 55 | 0.44 (0.25‐0.76) | ||
| Publication year | ||||||||
| <2010 | 135 743 | 9033 | 1.32 (1.06‐1.63) | 0.86 | 47 575 | 1638 | 1.43 (1.22‐1.67) | 0.68 |
| ≧2010 | 19 493 | 1607 | 1.20 (1.10‐1.31) | 89 499 | 3929 | 1.30 (0.89‐1.88) | ||
| Breast cancer staging | ||||||||
| 0 to II | 67 136 | 3670 | 1.21 (0.69‐2.11) | 0.43 | 41 332 | 1253 | 1.36 (1.01‐1.67) | 0.95 |
| I to IV | 88 100 | 6970 | 1.32 (1.14‐1.53) | 95 742 | 4114 | 1.39 (1.07‐1.82) | ||
| Surgery | ||||||||
| Breast‐conserving | 54 617 | 3369 | 0.60 (0.35‐1.04) | 0.20 | ··· | ··· | ··· | |
| Mastectomy | 10 681 | 735 | 1.47 (1.02‐2.12) | 11 319 | 472 | 1.59 (1.31‐1.94) | 0.10 | |
| Breast‐conserving or mastectomy | 89 938 | 6536 | 1.31 (1.13‐1.52) | 125 755 | 4895 | 1.21 (0.97‐1.52) | ||
| Follow‐up, year | ||||||||
| <20 | 72 870 | 4071 | 1.20 (0.88‐1.63) | 0.43 | 21 144 | 471 | 1.01 (0.71‐1.45) | 0.02 |
| ≧20 | 81 847 | 6430 | 1.32 (1.11‐1.57) | 115 807 | 4888 | 1.51 (1.29‐1.77) | ||
| Adjusted for risk profiles | ||||||||
| Yes | 148 875 | 10 484 | 1.26 (1.10‐1.44) | 0.31 | 110 750 | 4688 | 1.43 (1.22‐1.66) | 0.50 |
| No | 6361 | 156 | 2.10 (1.12‐3.95) | 26 324 | 679 | 1.28 (0.91‐1.80) | ||
| Adjuvant chemotherapy | ||||||||
| Yes | 116 751 | 9782 | 1.23 (1.03‐1.46) | 0.17 | 104 137 | 4399 | 1.25 (0.93‐1.68) | 0.40 |
| No | 38 485 | 858 | 1.42 (1.24‐1.62) | 32 937 | 968 | 1.50 (1.33‐1.71) | ||
| Patients, n | ||||||||
| <2000 | 4634 | 233 | 2.04 (1.36‐3.07) | 0.10 | 8899 | 358 | 1.26 (0.83‐1.92) | 0.47 |
| ≧2000 | 150 602 | 10 407 | 1.20 (1.05‐1.37) | 128 175 | 5009 | 1.43 (1.24‐1.66) | ||
| Age, y | ||||||||
| <55 | 8011 | 860 | 2.00 (1.21‐3.30) | 0.06 | 9363 | 272 | 1.11 (0.33‐3.80) | 0.81 |
| ≧55 | 144 511 | 9708 | 1.19 (1.03‐1.37) | 110 634 | 4551 | 1.31 (1.04‐1.64) | ||
| Source of patients | ||||||||
| Population based | 147 915 | 10 446 | 1.25 (1.09‐1.44) | 0.34 | 108 451 | 4364 | 1.14 (0.88‐1.48) | 0.09 |
| Hospital based | 7321 | 194 | 1.83 (1.12‐3.06) | 28 623 | 1003 | 1.56 (1.29‐1.89) | ||
| Case validation | ||||||||
| Yes | 5231 | 449 | 2.26 (1.43‐3.57) | 0.004 | 24 142 | 726 | 1.68 (1.23‐2.27) | 0.03 |
| No | 150 005 | 10 191 | 1.20 (1.05‐1.36) | 122 932 | 4641 | 1.25 (1.05‐1.50) | ||
| Period of breast cancer diagnosis | ||||||||
| <1980 | 9913 | 882 | 1.52 (1.29‐1.79) | 0.02 | 22 493 | 843 | 1.58 (1.39‐1.80) | 0.04 |
| ≧1980 | 70 699 | 6053 | 1.21 (1.01‐1.37) | 33 084 | 1060 | 1.27 (0.82‐1.97) | ||
| Years since breast cancer diagnosis | ||||||||
| 1 to 4 | 15 944 | 537 | 1.40 (1.12‐1.74) | NA | 22 211 | 212 | 1.04 (0.51‐2.12) | NA |
| 5 to 9 | 7596 | 408 | 1.70 (1.18‐2.45) | 11 672 | 149 | 1.17 (0.55‐2.48) | ||
| 10 to 14 | 9066 | 614 | 1.79 (1.08‐2.97) | 10 332 | 210 | 1.41 (1.04‐1.92) | ||
| 15 to 19 | 26 800 | 844 | 1.23 (1.02‐1.48) | 14 578 | 375 | 1.63 (1.21‐2.21) | ||
| >20 | 4612 | 259 | 1.88 (1.08‐3.27) | 13 324 | 1128 | 1.59 (1.33‐1.91) | ||
RCT indicates randomized controlled trial; RR, relative risk.
a
P‐Values test homogeneity between strata.