Introduction
Materials and methods
Study design
Population under study
Protocol
Data collection and measurement tools
Cancer registry and SEER linkage
Pathology reports
Stage determination
Grade
Estrogen receptor/progesterone receptor status
Reproductive/hormonal variables
Family history status
Statistical analysis
Tumor presentation
Survival analysis
Results
Characteristic | Frequency (n) | % |
---|---|---|
Age at diagnosis (years) | ||
20–24 | 7 | 2.7 |
25–29 | 55 | 21.6 |
30–34 | 192 | 75.6 |
Race/ethnicity | ||
Non-Hispanic white | 185 | 72.8 |
African-American | 17 | 6.7 |
Hispanic | 33 | 13.0 |
Asian/Pacific islander | 5 | 2.0 |
Native American | 1 | 0.4 |
Other | 13 | 5.1 |
Education | ||
Less than college degree | 143 | 56.3 |
College graduate | 111 | 43.7 |
Histology | ||
Infiltrating duct carcinoma | 193 | 76.0 |
Comedocarcinoma | 15 | 5.9 |
Medullary carcinoma | 9 | 3.5 |
Lobular carcinoma | 8 | 3.2 |
Infiltrating duct and lobular carcinoma | 8 | 3.2 |
Other | 21 | 8.3 |
Stage | ||
Localized | 131 | 51.6 |
Nonlocalized | 116 | 45.7 |
Unknown | 7 | 2.8 |
Grade/differentiation | ||
Grade I/well differentiated | 9 | 3.0 |
Grade II/moderately differentiated | 72 | 24.2 |
Grade III/poorly differentiated | 124 | 41.6 |
Grade IV/undifferentiated | 8 | 2.7 |
Grade not determined/not stated/NA | 85 | 28.5 |
Laterality | ||
Right | 132 | 52.0 |
Left | 122 | 48.0 |
Estrogen receptor status | ||
Positive | 92 | 36.2 |
Negative | 87 | 34.2 |
Borderline | 3 | 1.2 |
Unknown | 72 | 28.3 |
Progesterone receptor status | ||
Positive | 88 | 34.6 |
Negative | 85 | 33.5 |
Borderline | 3 | 1.2 |
Unknown | 78 | 30.7 |
Method of breast cancer detection | ||
Self examination | 205 | 80.7 |
Physician examination | 19 | 7.5 |
Mammography | 17 | 6.7 |
Other | 12 | 4.7 |
Missing | 1 | 0.4 |
Reproductive and hormonal factors and tumor characteristics
Reproductive and family history characteristics | Localized (n = 131) | Nonlocalized (n = 116) | ORa
| 95% CI |
P
|
---|---|---|---|---|---|
Age at menarche (years)b
| |||||
<12 | 26 (19.8) | 29 (25.4) | 1.0 (ref) | ||
≥ 12 | 105 (80.2) | 85 (74.6) | 0.8 | 0.4–1.4 | 0.35 |
Age at first full-term pregnancy (years) | |||||
No full-term pregnancies | 48 (36.6) | 29 (25.0) | 1.0 (ref) | ||
<20 | 12 (9.2) | 19 (16.4) | 3.0 | 1.2–7.4 | 0.02 |
20–24 | 31 (23.7) | 35 (30.2) | 2.1 | 1.0–4.3 | 0.04 |
25–29 | 25 (19.1) | 24 (20.7) | 1.7 | 0.8–3.6 | 0.15 |
30–34 | 15 (11.4) | 9 (7.8) | 1.1 | 0.4–2.9 | 0.86 |
Trend | <0.01 | ||||
Total live births | |||||
0 | 48 (36.6) | 29 (25.0) | 1.0 (ref) | ||
1–2 | 71 (54.2) | 67 (57.8) | 1.7 | 0.9–3.1 | 0.07 |
3 or more | 12 (9.2) | 20 (17.2) | 3.1 | 1.3–7.7 | 0.01 |
Trend | 0.01 | ||||
Total miscarriages (gravid women) | |||||
0 | 69 (74.2) | 67 (72.0) | 1.0 (ref) | ||
1 or more | 24 (25.8) | 26 (28.0) | 1.2 | 0.6–2.3 | 0.59 |
Total induced abortions (gravid women) | |||||
0 | 65 (69.9) | 59 (63.4) | 1.0 (ref) | ||
1 or more | 28 (30.1) | 34 (36.6) | 1.2 | 0.7–2.3 | 0.51 |
Breastfeeding (parous women) | |||||
Never | 25 (30.1) | 26 (29.9) | 1.0 (ref) | ||
Ever | 58 (69.9) | 61 (70.1) | 1.1 | 0.5–2.2 | 0.80 |
Months between last full-term pregnancy and diagnosis | |||||
No full-term pregnancy | 48 (36.6) | 29 (25.0) | 1.0 (ref) | ||
0–23 | 23 (17.6) | 26 (22.4) | 1.9 | 0.9–3.9 | 0.09 |
24 or more | 60 (45.8) | 61 (52.6) | 1.9 | 1.0–3.5 | 0.05 |
Trend | 0.06 | ||||
Oral contraceptive use | |||||
Never | 19 (14.5) | 21 (18.1) | 1.0 (ref) | ||
Ever | 112 (85.5) | 95 (81.9) | 0.8 | 0.4–1.5 | 0.43 |
Total months of oral contraceptive usec
| |||||
None | 19 (14.6) | 21 (18.9) | 1.0 (ref) | ||
1–35 | 35 (26.9) | 29 (26.1) | 0.6 | 0.3–1.3 | 0.22 |
36–83 | 33 (25.4) | 29 (26.1) | 0.7 | 0.3–1.4 | 0.30 |
84 or more | 43 (33.1) | 32 (28.8) | 0.6 | 0.3–1.2 | 0.17 |
Trend | 0.46 | ||||
Family history of breast or ovarian cancerd
| |||||
No family history | 109 (83.8) | 95 (82.6) | 1.0 (ref) | ||
Mother or sister | 21 (16.2) | 20 (17.4) | 1.2 | 0.6–2.3 | 0.67 |
Reproductive and hormonal | Grade 1–2 | Grade 3–4 | OR (for grade | 95% CI |
P
|
---|---|---|---|---|---|
Age at menarche (years) | |||||
<12 | 15 (18.8) | 33 (25.4) | 1.0 (ref) | ||
≥ 12 | 65 (81.2) | 97 (74.6) | 0.7 | 0.4–1.5 | 0.38 |
Age at first full-term pregnancy (years) | |||||
No full-term pregnancies | 27 (33.3) | 35 (26.5) | 1.0 (ref) | ||
<20 | 5 (6.2) | 23 (17.4) | 3.2 | 1.0–9.9 | 0.05 |
20–24 | 25 (30.9) | 34 (25.8) | 1.0 | 0.4–2.1 | 0.95 |
25–29 | 17 (21.0) | 26 (19.7) | 1.4 | 0.6–3.1 | 0.43 |
30–34 | 7 (8.6) | 14 (10.6) | 2.5 | 0.8–7.5 | 0.10 |
Trend | 0.27 | ||||
Total live births | |||||
0 | 27 (33.3) | 35 (26.5) | 1.0 (ref) | ||
1–2 | 45 (55.6) | 78 (58.3) | 1.5 | 0.8–2.8 | 0.25 |
3 or more | 9 (11.1) | 19 (15.2) | 1.7 | 0.6–4.6 | 0.30 |
Trend | 0.22 | ||||
Total miscarriages (gravid women) | |||||
0 | 50 (82.0) | 73 (70.2) | 1.0 (ref) | ||
1 or more | 11 (18.0) | 31 (29.8) | 2.0 | 0.9–4.5 | 0.08 |
Total induced abortions (gravid women) | |||||
0 | 40 (65.6) | 68 (65.4) | 1.0 (ref) | ||
1 or more | 21 (34.4) | 36 (34.6) | 1.0 | 0.5–1.9 | 0.92 |
Breastfeeding (parous women) | |||||
Never | 15 (27.8) | 34 (35.0) | 1.0 (ref) | ||
Ever | 39 (72.2) | 63 (65.0) | 0.8 | 0.4–1.6 | 0.51 |
Months between last full-term pregnancy and diagnosis | |||||
No full-term pregnancy | 27 (33.3) | 35 (26.5) | 1.0 (ref) | ||
0–23 | 19 (23.4) | 27 (20.4) | 1.2 | 0.5–2.6 | 0.71 |
≥ 24 | 35 (43.2) | 70 (53.0) | 1.7 | 0.9–3.5 | 0.12 |
Trend | 0.12 | ||||
Oral contraceptive use | |||||
Never | 10 (12.4) | 21 (15.9) | 1.0 (ref) | ||
Ever | 71 (87.6) | 111 (84.1) | 0.7 | 0.3–1.6 | 0.42 |
Total months of oral contraceptive useb
| |||||
None | 10 (13.2) | 21 (16.0) | 1.0 (ref) | ||
1–35 | 24 (31.6) | 32 (24.4) | 0.8 | 0.4–2.0 | 0.68 |
36–83 | 17 (22.4) | 38 (29.0) | 1.5 | 0.6–3.7 | 0.35 |
84 or more | 25 (32.9) | 40 (30.5) | 1.2 | 0.5–2.8 | 0.64 |
Trend | 0.78 | ||||
Family history of breast or ovarian cancerc
| |||||
No family history | 65 (80.2) | 113 (86.9) | 1.0 (ref) | ||
Mother or sister | 16 (19.8) | 17 (13.1) | 0.7 | 0.3–1.4 | 0.29 |
Reproductive and family history characteristics | ER-positive or borderline tumors (n = 95) | ER-negative tumors (n = 87) | ORa
| 95% CI |
P
|
---|---|---|---|---|---|
Age at menarche (years)b
| |||||
<12 | 16 (17.0) | 19 (22.4) | 1.0 (ref) | ||
≥ 12 | 78 (83.0) | 66 (77.6) | 0.7 | 0.3–1.5 | 0.42 |
Age at first full-term pregnancy (years) | |||||
No full-term pregnancies | 27 (28.4) | 27 (31.0) | 1.0 (ref) | ||
<20 | 10 (10.5) | 16 (18.4) | 1.5 | 0.6–4.0 | 0.43 |
20–24 | 26 (27.4) | 19 (21.8) | 0.7 | 0.3–1.6 | 0.39 |
25–29 | 23 (24.2) | 16 (18.4) | 0.7 | 0.3–1.7 | 0.45 |
30–34 | 9 (9.5) | 9 (10.3) | 1.2 | 0.4–3.6 | 0.80 |
Trend | 1.0 | ||||
Total live births | |||||
0 | 27 (28.4) | 27 (31.0) | 1.0 (ref) | ||
1–2 | 57 (60.0) | 49 (56.3) | 0.9 | 0.4–1.7 | 0.68 |
3 or more | 11 (11.6) | 11 (12.6) | 1.0 | 0.3–2.8 | 0.97 |
Trend | 0.86 | ||||
Total miscarriages (gravid women) | |||||
0 | 61 (80.3) | 42 (65.6) | 1.0 (ref) | ||
1 or more | 15 (19.7) | 22 (34.4) | 2.1 | 1.0–4.6 | 0.05 |
Total induced abortions (gravid women) | |||||
0 | 48 (63.2) | 44 (68.8) | 1.0 (ref) | ||
1 or more | 28 (26.8) | 20 (31.2) | 0.7 | 0.4–1.5 | 0.42 |
Breastfeeding (parous women) | |||||
Never | 12 (17.6) | 29 (48.3) | 1.0 (ref) | ||
Ever | 56 (82.4) | 31 (51.7) | 0.2 | 0.1–0.5 | <0.001 |
Months between last full-term pregnancy and diagnosis | |||||
No full-term pregnancy | 27 (28.4) | 27 (31.0) | 1.0 (ref) | ||
0–23 | 19 (20.0) | 16 (18.4) | 0.9 | 0.4–2.0 | 0.71 |
≥ 24 | 49 (51.6) | 44 (50.6) | 0.9 | 0.4–1.8 | 0.77 |
Trend | 0.78 | ||||
Oral contraceptive use | |||||
Never | 19 (20.0) | 12 (13.8) | 1.0 (ref) | ||
Ever | 76 (80.0) | 75 (86.2) | 1.6 | 0.7–3.4 | 0.28 |
Total months of oral contraceptive usec
| |||||
None | 19 (20.2) | 12 (14.6) | 1.0 (ref) | ||
1–35 | 24 (25.5) | 23 (28.0) | 1.1 | 0.5–2.6 | 0.81 |
36–83 | 16 (17.0) | 20 (24.4) | 1.5 | 0.6–3.7 | 0.42 |
84 or more | 35 (37.2) | 27 (32.9) | 0.9 | 0.4–2.1 | 0.85 |
Trend | 0.78 | ||||
Family history of breast or ovarian cancerd
| |||||
No family history | 75 (79.8) | 71 (82.6) | 1.0 (ref) | ||
Mother or sister | 19 (20.2) | 15 (17.4) | 0.9 | 0.4–1.9 | 0.72 |
Reproductive and family history characteristics | PgR-positive or borderline tumors (n = 91) | PgR-negative tumors (n = 85) | ORa
| 95% CI |
P
|
---|---|---|---|---|---|
Age at menarche (years)b
| |||||
<12 | 14 (15.6) | 21 (25.3) | 1.0 (ref) | ||
≥ 12 | 76 (84.4) | 62 (74.7) | 0.6 | 0.3–1.2 | 0.14 |
Age at first full-term pregnancy | |||||
No full-term pregnancies | 27 (29.7) | 25 (29.4) | 1.0 (ref) | ||
<20 | 10 (11.0) | 15 (17.6) | 1.6 | 0.6–4.4 | 0.37 |
20–24 | 25 (27.5) | 20 (23.5) | 0.8 | 0.4–2.0 | 0.71 |
25–29 | 19 (20.9) | 18 (21.2) | 1.1 | 0.5–2.6 | 0.82 |
30–34 | 10 (11.0) | 7 (8.2) | 0.9 | 0.3–2.9 | 0.88 |
Trend | 0.65 | ||||
Total live births | |||||
0 | 27 (29.7) | 25 (29.4) | 1.0 (ref) | ||
1–2 | 53 (58.2) | 50 (58.8) | 1.1 | 0.5–2.1 | 0.87 |
3 or more | 11 (12.1) | 10 (11.8) | 1.0 | 0.3–2.9 | 1.00 |
Trend | 0.95 | ||||
Total miscarriages (gravid women) | |||||
0 | 54 (76.1) | 45 (69.2) | 1.0 (ref) | ||
1 or more | 17 (23.9) | 20 (30.8) | 1.4 | 0.7–3.0 | 0.38 |
Total induced abortions (gravid women) | |||||
0 | 46 (64.8) | 44 (67.7) | 1.0 (ref) | ||
1 or more | 25 (35.2) | 21 (32.3) | 0.8 | 0.4–1.7 | 0.65 |
Breastfeeding (parous women) | |||||
Never | 14 (21.9) | 25 (41.7) | 1.0 (ref) | ||
Ever | 50 (78.1) | 35 (58.3) | 0.4 | 0.2–0.8 | 0.02 |
Months between last full-term pregnancy and diagnosis | |||||
No full-term pregnancy | 27 (29.7) | 25 (29.4) | 1.0 (ref) | ||
0–23 | 17 (18.7) | 16 (18.8) | 1.0 | 0.4–2.5 | 0.95 |
≥ 24 | 47 (51.6) | 44 (51.8) | 1.1 | 0.5–2.2 | 0.87 |
Trend | 0.87 | ||||
Oral contraceptive use | |||||
Never | 19 (20.9) | 10 (11.8) | 1.0 (ref) | ||
Ever | 72 (79.1) | 75 (88.2) | 2.0 | 0.8–4.6 | 0.11 |
Total months of oral contraceptive usec
| |||||
None | 19 (21.3) | 10 (12.2) | 1.0 (ref) | ||
1–35 | 23 (25.8) | 23 (28.0) | 1.6 | 0.6–3.9 | 0.33 |
36–83 | 14 (15.7) | 20 (24.4) | 2.3 | 0.9–6.1 | 0.10 |
84 or more | 33 (37.1) | 29 (35.4) | 1.5 | 0.6–3.5 | 0.38 |
Trend | 0.34 | ||||
Family history of breast or ovarian cancerd
| |||||
No family history | 71 (78.9) | 70 (83.3) | 1.0 (ref) | ||
Mother or sister | 19 (21.1) | 14 (16.7) | 0.8 | 0.4–1.8 | 0.58 |