Table 4.
Risk of breast cancer among women diagnosed with HL at age 30 years or younger according to radiotherapy and history of a live birth
|
Among women who did not receive AA and who received RT to ovaries < 5 Gy*†: patients, n = 68 and matched control subjects, n = 125
|
||||||
|---|---|---|---|---|---|---|
| Characteristic | Exposure | Patients, no. (%) | Control subjects, no. (%) | Adjusted OR (95% CI) | Effect ≥ 5 Gy, OR (95% CI) | |
| Live birth‡ | RT > 5 Gy | No live births | Live births | |||
| No | No | 5 (7.4) | 7 (5.6) | 1.0 (reference) | 1.0 (reference) | — |
| No | Yes | 12 (17.6) | 22 (17.6) | 1.1 (0.3-4.7) | 1.1 (0.3-4.7) | — |
| Yes | No | 10 (14.7) | 39 (31.2) | 0.4 (0.1-1.6) | — | 1.0 (reference) |
| Yes | Yes | 41 (60.3) | 55 (44.0) | 1.4 (0.4-4.8)§ | — | 3.5 (1.4-8.9) |
| Unknown | — | 0 | 2 (1.6) | — | — | — |
—indicates not calculated; reference, the reference group for the odds ratio comparison.
Women who had an unknown breast radiation dose (n = 1 case; 7 controls) or an unknown ovarian dose (n = 4 controls) were assigned the median dose in controls (2300 cGy, 44.5 cGy, respectively) in these analyses.
As these treatments can induce menopause and influence the probability of having a live birth, exposed women were excluded from this analysis.
Information regarding stillbirths, which are included in the definition of parity, was not collected for some women, thus only live births are included.
Interaction OR (multiplicative scale): breast dose of 5 Gy or more and ever had a live birth, 3.1 (95% CI, 0.6-17.2); breast dose on a continuous scale and ever had a live birth, 1.06 (95% CI, 1.01-1.12). Interaction contrast ratio (ICR; additive RR scale: breast dose of 5 Gy or more and ever had a live birth, 0.93 (-1.8-+3.36); breast dose on a continuous scale and ever had a live birth, 0.05 (95% CI, -.20-+.22).