Table 4.
Standardised incidence ratios (SIRs) for invasive and in situ breast cancer and invasive and borderline tumours of the ovary among 255 786 women who underwent assisted reproduction in Great Britain, 1991-2010, stratified by various factors*
| Factor | Follow-up (No of person years) | Invasive breast cancer† | In situ breast cancer‡ | Invasive ovarian tumours§ | Borderline ovarian tumours¶ | |||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| No of observed cancers | SIR (95% CI) | No of observed cancers | SIR (95% CI) | No of observed cancers | SIR (95% CI) | No of observed cancers | SIR (95% CI) | |||||
| Overall | 2 257 789 | 2272 | 0.96 (0.92 to 1.00) | 291 | 1.15 (1.02 to 1.29) | 264 | 1.40 (1.24 to 1.58) | 141 | 1.36 (1.15 to 1.60) | |||
| Age at first treatment (years) | ||||||||||||
| <25 | 48 187 | 14 | 1.43 (0.78 to 2.39) | 0 | 0.00 (0.00 to 4.34) | <5 | ** | <5 | ** | |||
| 25-29 | 38 964 | 168 | 0.91 (0.78 to 1.06) | 16 | 1.10 (0.63 to 1.78) | 35 | 2.33 (1.63 to 3.25) | 29 | 1.98 (1.33 to 2.85) | |||
| 30-34 | 866 351 | 685 | 0.92 (0.86 to 1.00) | 85 | 1.27 (1.02 to 1.57) | 81 | 1.46 (1.16 to 1.82) | 61 | 1.61 (1.23 to 2.07) | |||
| 35-39 | 714 056 | 925 | 0.97 (0.91 to 1.04) | 100 | 0.94 (0.77 to 1.15) | 97 | 1.32 (1.07 to 1.61) | 37 | 1.04 (0.73 to 1.43) | |||
| 40-44 | 218 767 | 411 | 1.00 0.90 to 1.10) | 66 | 1.23 (0.95 to 1.56) | 40 | 1.13 (0.80 to 1.53) | 10 | 0.82 (0.39 to 1.50) | |||
| ≥45 | 28 463 | 69 | 0.94 (0.73 to 1.19) | 24 | 2.12 (1.36 to 3.15) | <10 | ** | <5 | ** | |||
| Trend across categories | — | P=0.30 | P=0.47 | P=0.02 | P<0.001 | |||||||
| Infertility cause | ||||||||||||
| Any female factor | 1 109 593 | 1118 | 0.92 (0.87 to 0.98) | 151 | 1.14 (0.97 to 1.34) | 161 | 1.66 (1.41 to 1.94) | 85 | 1.66 (1.33 to 2.05) | |||
| Male factor only | 757 063 | 676 | 0.89 (0.83 to 0.96) | 93 | 1.18 (0.95 to 1.44) | 65 | 1.09 (0.84 to 1.39) | 33 | 0.96 (0.66 to 1.35) | |||
| Unexplained | 326 495 | 374 | 1.10 (0.99 to 1.22) | 42 | 1.18 (0.85 to 1.59) | 26 | 0.98 (0.64 to 1.44) | 14 | 0.92 (0.50 to 1.55) | |||
| Unrecorded | 64 638 | 104 | 1.58 (1.30 to 1.92) | 5 | 0.73 (0.24 to 1.70) | 12 | 2.35 (1.21 to 4.10) | 9 | 3.00 (1.37 to 5.70) | |||
| History of endometriosis | ||||||||||||
| Yes | 181 279 | 186 | 0.95 (0.82 to 1.10) | 26 | 1.25 (0.81 to 1.83) | 38 | 2.47 (1.75 to 3.39) | 17 | 2.03 (1.18 to 3.25) | |||
| No | 2 076 509 | 2086 | 0.96 (0.92 to 1.00) | 265 | 1.14 (1.01 to 1.28) | 226 | 1.31 (1.14 to 1.49) | 124 | 1.30 (1.08 to 1.55) | |||
| History of tubal disease | ||||||||||||
| Yes | 710 522 | 725 | 0.94 (0.87 to 1.01) | 92 | 1.11 (0.89 to 1.36) | 105 | 1.71 (1.40 to 2.08) | 53 | 1.62 (1.21 to 2.12) | |||
| No | 1 547 266 | 1547 | 0.97 (0.92 to 1.01) | 199 | 1.17 (1.01 to 1.34) | 159 | 1.25 (1.07 to 1.46) | 88 | 1.24 (0.99 to 1.53) | |||
| History of ovulatory problems | ||||||||||||
| Yes | 311 523 | 315 | 0.91 (0.81 to 1.02) | 41 | 1.05 (0.75 to 1.42) | 33 | 1.16 (0.80 to 1.63) | 22 | 1.52 (0.96 to 2.31) | |||
| No | 1 946 265 | 1957 | 0.97 (0.92 to 1.01) | 250 | 1.17 (1.03 to 1.32) | 231 | 1.45 (1.27 to 1.65) | 119 | 1.33 (1.11 to 1.60) | |||
| Duration of infertility at last cycle (years) | ||||||||||||
| <2 | 133 067 | 156 | 0.97 (0.83 to 1.14) | 15 | 0.82 (0.46 to 1.35) | 16 | 1.23 (0.70 to 1.99) | 12 | 1.89 (0.98 to 3.30) | |||
| 2-3 | 439 560 | 464 | 1.03 (0.94 to 1.13) | 61 | 1.26 (0.97 to 1.62) | 53 | 1.48 (1.11 to 1.93) | 20 | 0.99 (0.61 to 1.53) | |||
| 4-5 | 447 739 | 461 | 0.97 (0.89 to 1.07) | 52 | 1.03 (0.77 to 1.35) | 53 | 1.42 (1.06 to 1.85) | 21 | 1.02 (0.63 to 1.55) | |||
| 6-7 | 271 583 | 278 | 0.90 (0.79 to 1.01) | 35 | 1.03 (0.72 to 1.44) | 40 | 1.63 (1.16 to 2.21) | 20 | 1.57 (0.96 to 2.42) | |||
| 8-9 | 151 580 | 169 | 0.92 (0.78 to 1.06) | 27 | 1.31 (0.86 to 1.91) | 27 | 1.84 (1.21 to 2.67) | 9 | 1.24 (0.57 to 2.36) | |||
| ≥10 | 209 751 | 279 | 0.92 (0.82 to 1.04) | 42 | 1.15 (0.83 to 1.56) | 40 | 1.60 (1.14 to 2.18) | 17 | 1.61 (0.94 to 2.58) | |||
| Unrecorded | 324 953 | 355 | 1.05 (0.94 to 1.16) | 48 | 1.37 (1.01 to 1.82) | 25 | 0.97 (0.63 to 1.43) | 17 | 1.12 (0.65 to 1.79) | |||
| Trend across categories | — | P=0.11 | P=0.58 | P=0.25 | P=0.42 | |||||||
| Total number of stimulated cycles | ||||||||||||
| 0 (“natural cycle” only) | 90 973 | 121 | 0.85 (0.71 to 1.02) | 21 | 1.14 (0.71 to 1.74) | 13 | 1.04 (0.55 to 1.78) | <5 | ** | |||
| 1 | 1 041 791 | 1073 | 0.97 (0.91 to 1.03) | 121 | 1.02 (0.85 to 1.22) | 129 | 1.47 (1.23 to 1.75) | 67 | 1.39 (1.08 to 1.77) | |||
| 2 | 473 125 | 512 | 0.98 (0.90 to 1.07) | 70 | 1.25 (0.97 to 1.58) | 56 | 1.37 (1.03 to 1.78) | 31 | 1.40 (0.95 to 1.98) | |||
| 3-4 | 306 137 | 371 | 1.01 (0.92 to 1.12) | 47 | 1.18 (0.87 to 1.57) | 42 | 1.48 (1.06 to 1.99) | 11 | 0.75 (0.37 to 1.33) | |||
| ≥5 | 66 149 | 85 | 0.96 (0.77 to 1.91) | 21 | 2.11 (1.31 to 3.23) | 14 | 2.04 (1.11 to 3.42) | <5 | ** | |||
| Trend across categories | — | P=0.27 | P=0.03 | P=0.29 | P=0.18 | |||||||
| Total number of live births after last treatment | ||||||||||||
| 0 | 1 009 134 | 1154 | 0.98 (0.92 to 1.04) | 135 | 1.04 (0.87 to 1.23) | 156 | 1.67 (1.42 to 1.95) | 66 | 1.38 (1.07 to 1.75) | |||
| 1 | 718 998 | 732 | 0.99 (0.92 to 1.07) | 107 | 1.37 (1.12 to 1.65) | 78 | 1.34 (1.06 to 1.67) | 36 | 1.09 (0.76 to 1.51) | |||
| ≥2 | 249 685 | 276 | 0.90 (0.80 to 1.02) | 37 | 1.07 (0.76 to 1.48) | 20 | 0.81 (0.50 to 1.26) | 14 | 1.16 (0.63 to 1.95) | |||
| Unrecorded | 414 | 0 | 0.00 | 1 | 20.00 (0.51 to 111.43) | 0 | 0.00 (0.00 to 74.89) | 0 | 0.0 (0.0 to 149.79) | |||
| Trend across categories | — | P=0.37 | P=0.32 | P=0.001 | P=0.34 | |||||||
| Any multiple birth recorded | ||||||||||||
| Yes | 232 824 | 234 | 1.10 (0.97 to 1.25) | 22 | 1.05 (0.66 to 1.58) | 22 | 1.34 (0.84 to 2.03) | 11 | 1.06 (0.53 to 1.90) | |||
| No | 1 745 409 | 1928 | 0.96 (0.92 to 1.00) | 258 | 1.16 (1.02 to 1.31) | 232 | 1.45 (1.27 to 1.65) | 105 | 1.27 (1.04 to 1.54) | |||
| Time since last treatment (years) | ||||||||||||
| 0-3 | 687 180 | 488 | 1.05 (0.96 to 1.15) | 37 | 1.06 (0.71 to 1.39) | 62 | 1.73 (1.33 to 2.22) | 37 | 1.30 (0.92 to 1.79) | |||
| 3-6 | 486 191 | 476 | 1.03 (0.94 to 1.12) | 51 | 1.24 (0.93 to 1.63) | 45 | 1.27 (0.93 to 1.71) | 28 | 1.27 (0.85 to 1.84) | |||
| 6-10 | 444 324 | 556 | 0.94 (0.87 to 1.02) | 95 | 1.52 (1.23 to 1.85) | 63 | 1.37 (1.05 to 1.75) | 21 | 0.96 (0.59 to 1.46) | |||
| ≥10 | 296 445 | 510 | 0.93 (0.85 to 1.01) | 75 | 0.98 (0.77 to 1.22) | 63 | 1.38 (1.06 to 1.77) | 23 | 1.39 (0.88 to 2.08) | |||
| ≥15 | 64 091 | 132 | 0.86 (0.72 to 1.02) | 22 | 0.85 (0.54 to 1.29) | 21 | 1.52 (0.94 to 2.32) | 7 | 1.75 (0.70 to 3.60) | |||
| Trend across categories | — | P=0.005 | P=0.29 | P=0.44 | P=0.84 | |||||||
*
See supplementary appendix for results excluding the first 12 months of follow-up.
†
Invasive breast cancer=ICD-9 codes 1740-1749 and ICD-10 codes C500-C509.
‡
In situ breast cancer=ICD-9 code 2330 and ICD-10 code D050-D059.
§
Invasive ovarian tumours=ICD-9 codes 1830-1839 (excluding morphology codes 8442/8451/8462/8472/8473) and 2362; ICD-10 codes C56, C570-C574, C481, and C482 (excluding morphology codes 8442/8451/8462/8472/8473).
¶
Borderline ovarian tumours=ICD-9 code 1830 (with morphology codes 8442/8451/8462/8472/8473) and ICD-10 codes D391 and C56 (with morphology codes 8442/8451/8462/8472/8473).
**
Data suppressed to comply with data disclosure regulations where cells relate to small numbers of individuals. None of the standardised incidence ratios for affected cells approached significance.