Table 1.
Stratified Analysis and Heterogeneity Analysis of Relative Risks of Coronary Heart Disease and Cardiac Mortality in Left‐Sided Versus Right‐Sided Radiotherapy
| Factors Stratified | Coronary Heart Disease | Cardiac Mortality | ||||||
|---|---|---|---|---|---|---|---|---|
| Patients | Events | RR (95%CI) | P Valuea | Patients | Events | RR (95%CI) | P Valuea | |
| All studies | 233 761 | 2723 | 1.29 (1.13‐1.48) | 239 434 | 11 810 | 1.22 (1.08‐1.37) | ||
| Types of studies | ||||||||
| Observational studies | 231 876 | 2666 | 1.30 (1.13‐1.48) | 0.65 | 232 006 | 11 479 | 1.16 (1.01‐1.32) | 0.10 |
| RCT | 1885 | 57 | 2.07 (0.28‐15.05) | 7428 | 331 | 1.44 (1.18‐1.76) | ||
| Location | ||||||||
| Europe | 27 024 | 1668 | 1.14 (1.01‐1.29) | 0.01 | 115 344 | 8005 | 1.14 (1.01‐1.29) | 0.65 |
| North America | 10 921 | 409 | 1.65 (1.16‐2.34) | 6805 | 562 | 1.37 (0.88‐2.13) | ||
| Publication year | ||||||||
| <2010 | 223 687 | 1572 | 1.42 (1.19‐1.69) | 0.03 | 192 265 | 9925 | 1.34 (1.11‐1.62) | 0.08 |
| ≧2010 | 10 074 | 1151 | 1.14 (1.04‐1.25) | 47 169 | 1885 | 1.03 (0.93‐1.14) | ||
| Breast cancer staging | ||||||||
| 0 to II | 7143 | 300 | 1.38 (0.90‐2.11) | 0.69 | 36 152 | 866 | 1.40 (1.22‐1.61) | <0.001 |
| I to IV | 226 618 | 2423 | 1.27 (1.12‐1.43) | 131 838 | 8648 | 1.07 (0.97‐1.17) | ||
| Surgery | ||||||||
| Breast‐conserving | 6130 | 291 | 1.80 (1.21‐2.66) | 0. 02 | 98 148 | 7921 | 1.12 (1.00‐1.25) | 0.58 |
| Mastectomy | 7414 | 331 | 1.05 (0.77‐1.43) | 68 621 | 2922 | 1.30 (1.03‐1.64) | ||
| Breast‐conserving or mastectomy | 220 217 | 2101 | 1.24 (1.09‐1.42) | 23 774 | 1207 | 1.08 (0.88‐1.33) | ||
| Follow‐up, y | ||||||||
| <20 | 15 797 | 483 | 1.35 (0.93‐1.94) | 1.00 | 47 169 | 1885 | 1.18 (0.93‐1.52) | 0.52 |
| ≧20 | 217 892 | 2207 | 1.28 (1.14‐1.44) | 192 265 | 9925 | 1.25 (1.08‐1.45) | ||
| Adjusted for risk profiles | ||||||||
| Yes | 221 489 | 1440 | 1.30 (1.12‐1.53) | 0.83 | 232 387 | 11 485 | 1.35 (1.08‐1.69) | 0.33 |
| No | 12 272 | 1283 | 1.36 (1.03‐1.78) | 7047 | 325 | 1.18 (1.03‐1.35) | ||
| Adjuvant chemotherapy | ||||||||
| Yes | 214 908 | 2237 | 1.35 (1.12‐1.63) | 0.38 | 159 218 | 4986 | 1.13 (0.92‐1.39) | 0.30 |
| No | 18 853 | 486 | 1.20 (1.01‐1.42) | 80 216 | 6824 | 1.32 (1.08‐1.60) | ||
| Patients, n | ||||||||
| <2000 | 8123 | 385 | 1.42 (1.02‐1.97) | 0.47 | 8698 | 335 | 1.41 (1.08‐1.84) | 0.11 |
| ≧2000 | 225 638 | 2338 | 1.25 (1.10‐1.43) | 230 736 | 11 475 | 1.15 (1.01‐1.30) | ||
| Age, y | ||||||||
| <55 | 9659 | 498 | 1.23 (1.09‐1.38) | 0.11 | 3307 | 109 | 1.49 (1.01‐2.19) | 0.21 |
| ≧55 | 224 102 | 2225 | 1.60 (1.10‐2.34) | 229 381 | 11 460 | 1.13 (0.99‐1.28) | ||
| Source of patients | ||||||||
| Population based | 227 067 | 2467 | 1.28 (1.09‐1.50) | 0.83 | 176 405 | 5621 | 1.26 (1.07‐1.48) | 0.49 |
| Hospital based | 6694 | 256 | 1.33 (0.97‐1.83) | 63 029 | 6189 | 1.16 (0.92‐1.48) | ||
| Case validation | ||||||||
| Yes | 6640 | 1166 | 1.66 (1.09‐2.54) | 0.03 | 9012 | 323 | 1.56 (1.28‐1.91) | 0.01 |
| No | 227 121 | 1557 | 1.26 (1.10‐1.44) | 230 422 | 11 487 | 1.12 (1.00‐1.27) | ||
| Period of breast cancer diagnosis | ||||||||
| <1980 | 84 335 | 5046 | 1.32 (1.21‐1.44) | 0.04 | 81 730 | 10 855 | 1.45 (1.14‐1.89) | 0.04 |
| ≧1980 | 88 680 | 3455 | 1.16 (1.01‐1.33) | 143 606 | 6680 | 1.15 (0.92‐1.44) | ||
| Years since breast cancer diagnosis | ||||||||
| 1 to 4 | 308 190 | 1534 | 1.14 (0.95‐1.36) | NA | 173 683 | 4794 | 1.02 (0.96‐1.08) | NA |
| 5 to 9 | 303 821 | 1445 | 1.17 (1.04‐1.32) | 166 014 | 2801 | 1.05 (0.97‐1.14) | ||
| 10 to 14 | 302 376 | 1250 | 1.93 (1.13‐3.30) | 164 387 | 1125 | 1.26 (1.11‐1.44) | ||
| 15 to 20 | 285 165 | 736 | 1.39 (1.08‐1.79) | 124 462 | 929 | 1.44 (1.14‐1.82) | ||
RCT indicates randomized controlled trial; RR, relative risk.
a
P‐values test homogeneity between strata.