Table 2.
Risk of breast cancer among women diagnosed with Hodgkin lymphoma (HL) at age 30 years or younger according to treatment for HL and breast cancer risk factors
| Patients, no. (%) | Matched control subjects, no. (%) | Odds ratio adjusted,*(95% CI) | |
|---|---|---|---|
| Among all women: patients, n = 105 and matched control subjects, n = 266 | |||
| Age at menarche, y | |||
| Older than 12 | 43 (41.0) | 106 (39.8) | 1.0 |
| 12 or younger | 28 (26.7) | 51 (19.2) | 1.2 (0.7-2.3) |
| Unknown | 34 (32.3) | 109 (41.0) | — |
| Body mass index at HL diagnosis, kg/m2† | |||
| Less than 19.5 | 30 (28.6) | 53 (20.0) | 1.0 |
| 19.5-21.1 | 14 (13.3) | 52 (19.5) | 0.5 (0.2-1.2) |
| 21.2-23.3 | 17 (16.2) | 51 (19.2) | 0.5 (0.2-1.1) |
| 23.4 or greater | 14 (13.3) | 52 (19.5) | 0.4 (0.2-0.9) |
| Unknown | 30 (28.6) | 58 (21.8) | — |
| 1st or 2nd degree relative with breast or ovarian cancer | |||
| No | 46 (43.8) | 129 (48.5) | 1.0 |
| Yes | 28 (26.7) | 28 (10.5) | 2.5 (1.2-5.3) |
| Unknown | 46 (43.8) | 129 (48.5) | 1.0 |
| Menopausal status‡# | |||
| Pre/perimenopausal | |||
| No AA and radiation to ovaries, lower than 5 Gy | 51 (72.9) | 86 (64.7) | 1.0 |
| AA or radiation to ovaries, 5 Gy or higher | 20 (27.1) | 47 (35.3) | 0.7 (0.3-1.5) |
| Postmenopausal | |||
| No AA and radiation to ovaries, less than 5 Gy | 11 (52.0) | 13 (15.3) | 1.0 |
| AA or radiation to ovaries ≥ 5 Gy | 12 (48.0) | 72 (84.7) | 0.2 (0.1-1.3) |
| Unknown | 11 | 48 | — |
| Treatment for HL, radiation dose to specific breast location, Gy | |||
| 0-4.9 | 23 (21.9) | 95 (3517) | 1.0 |
| 5.0-61.3 | 82 (78.1) | 171 (64.3) | 2.7 (1.4-5.2) |
| Risk per Gy | — | — | 1.04 (1.0-1.07) |
| Among women who did not receive AA and who received RT to ovaries lower than 5 Gy: patients, n = 68; matched control subjects, n = 125 | |||
| Ever had a live birth§ | |||
| No | 17 (25.0) | 29 (23.2) | 1.0 |
| Yes | 51 (75.0) | 94 (75.2) | 0.9 (0.4-1.9) |
| Unknown | 0 | 2 (1.6) | — |
| Age at first live birth, y∥¶ | |||
| 22 or younger | 15 (22.1) | 27 (21.6) | 1.0 |
| 23-26 | 19 (27.9) | 29 (23.2) | 1.0 (0.5-2.2) |
| 27 or older | 16 (23.5) | 32 (25.6) | 0.9 (0.4-2.2) |
| Unknown | 1 (1.5) | 8 (6.4) | — |
| Nulliparous or no live births | 17 (25.0) | 29 (23.2) | — |
| No. of live births‡¶∥ | |||
| 1 | 14 (20.6) | 20 (16.0) | 1.0 |
| 2 | 19 (27.9) | 44 (35.2) | 0.8 (0.3-2.4) |
| 3 or more | 18 (26.5) | 30 (24.0) | 0.9 (0.3-2.5) |
| Unknown | 0 | 2 (1.6) | — |
| Nulliparous or no live births | 17 (25.0) | 29 (23.2) | — |
| Timing of live births∥¶ | |||
| All live births before HL | 14 (20.6) | 20 (16.0) | 1.0 |
| All live births after HL | 27 (39.7) | 51 (40.8) | 0.8 (0.3-2.1) |
| Live births before and after HL | 10 (14.7) | 18 (14.4) | 0.7 (0.3-2.1) |
| Unknown | 0 | 7 (5.6) | — |
| Nulliparous or no live births | 17 (25.0) | 29 (23.2) | — |
| Oral contraceptive use§ | |||
| Never | 20 (29.4) | 29 (23.2) | 1.0 |
| Ever | 37 (54.4) | 77 (61.6) | 1.0 (0.5-2.2) |
| 1-6 y | 9 (13.2) | 29 (23.2) | 0.9 (0.3-2.4) |
| 7 or more y | 20 (29.4) | 28 (22.4) | 1.9 (0.7-5.0) |
| Duration unknown | 8 (11.8) | 20 (16.0) | — |
| Unknown | 11 (16.2) | 19 (15.2) | — |
—indicates not calculated.
All risk factor analyses were adjusted for breast radiation dose, ovarian radiation dose, and number of cycles of AA chemotherapy. Women who had an unknown radiation dose to the breast (1 patient, 7 control subjects) or an unknown radiation dose to the ovaries (4 control subjects) were assigned the median dose in controls, 23.0 Gy or 0.44 Gy, respectively.
Pre- and postmenopausal women did not differ in breast cancer risk according to body mass index (measured at the time of HL diagnosis), thus only combined results are presented. P = .02 for trend in risk by quartile of body mass index; P = .01 for trend in risk by body mass index on a continuous scale.
Adjusted for breast radiation dose only. Treatment with AA chemotherapy or receiving a dose to the ovary of 5 Gy or higher can induce menopause; odds ratios presented separately for those that received such treatment to illustrate the need to exclude these women from selected analyses. When adjusted only for breast radiation dose, all postmenopausal women combined had a reduced breast cancer risk (OR 0.3; 95% CI 0.2-0.7), relative to pre/perimenopausal women.
As treatment with AA chemotherapy or receiving a dose to the ovary 5 Gy or higher could potentially influence the timing and number of children by reducing fertility, women who received these treatments (n = 37 patients, 141 control subjects) were considered unexposed in these analyses and placed in a separate category by an indicator variable.
Among women who had experienced a live birth only.
Analyses regarding age at first live birth were adjusted for number of live births (1, 2, or 3 or more) and analyses regarding number of live births and timing of live births were adjusted for age at first live birth (22 years and younger, 23-26 years, or 27 or older).
At breast cancer diagnosis (patients) or study cutoff date (control subjects).