Table 1. Baseline demographic and clinicopathologic characteristics of the 796,335 study patients.
| Characteristic | ILC% (n = 85,048) |
IDC % (n = 711,287) |
P |
|---|---|---|---|
| Age at diagnosis, years | <0.0001 | ||
| <40 | 1.7 | 5.9 | |
| 40–60 | 34.9 | 41.8 | |
| >60 | 63.4 | 52.3 | |
| Marital status | 0.001c | ||
| Single | 45.0 | 42.9 | |
| Married | 55.0 | 57.1 | |
| Tumor site(s) | <0.0001 c | ||
| Only one site (left or right) | 99.6 | 99.9 | |
| Two or more sites | 0.4 | 0.1 | |
| Tumor size, mm | <0.0001 c | ||
| No tumor | 0.3 | 0.1 | |
| < = 20 | 50.7 | 61.5 | |
| 21–40 | 27.9 | 26.8 | |
| > = 41 | 21.1 | 11.7 | |
| Tumor stage | <0.0001 c | ||
| 0 | 0.0 | 0.0 | |
| I-II | 76.8 | 83.7 | |
| III-IV | 23.2 | 16.3 | |
| Tumor grade | <0.0001 c | ||
| I | 28.4 | 18.2 | |
| II | 57.0 | 41.6 | |
| III | 13.7 | 38.7 | |
| Undifferentiated | 0.9 | 1.5 | |
| Breast–Adjusted AJCC 6th T | <0.0001 c | ||
| T0 | 0.0 | 0.0 | |
| Tis | 0.0 | 0.0 | |
| T1-2 | 81.6 | 89.5 | |
| T3-4 | 12.4 | 6.4 | |
| Any T, Mets | 5.9 | 4.1 | |
| Breast–Adjusted AJCC 6th N | <0.0001 | ||
| N0 | 59.1 | 62.0 | |
| N1 | 18.9 | 21.0 | |
| N2 | 7.0 | 6.1 | |
| N3 | 6.4 | 3.8 | |
| NX | 8.6 | 7.1 | |
| Breast–Adjusted AJCC 6th M | <0.0001 | ||
| M0 | 92.3 | 94.2 | |
| M1 | 5.5 | 3.8 | |
| MX | 2.2 | 1.9 | |
| Lymph node, positive counts | <0.0001 c | ||
| Negative | 63.2 | 66.6 | |
| 1–3 | 21.1 | 22.8 | |
| 4–10 | 9.6 | 7.8 | |
| >10 | 6.0 | 2.8 | |
| ER status | <0.0001 c | ||
| positive | 94.8 | 76.6 | |
| negative | 5.0 | 23.1 | |
| Borderline | 0.2 | 0.3 | |
| PR status | <0.0001 c | ||
| positive | 78.1 | 65.7 | |
| negative | 21.2 | 33.6 | |
| Borderline | 0.7 | 0.6 | |
| ER/PR statusb | <0.0001 | ||
| ER+/PR+ | 77.8 | 64.5 | |
| ER+/PR- | 17.2 | 12.3 | |
| ER-/PR+ | 0.9 | 1.8 | |
| ER-/PR- | 4.1 | 21.5 | |
| HER2 statusa | <0.0001 | ||
| positive | 4.8 | 16.4 | |
| negative | 93.5 | 81.1 | |
| Borderline | 1.7 | 2.4 | |
| Cancer directed surgery | <0.0001 c | ||
| Not performed | 8.3 | 6.3 | |
| Breast conserving surgery | 40.9 | 53.2 | |
| Mastectomy | 50.7 | 40.3 | |
| Surgery, NOS | 0.2 | 0.1 | |
| Radiation | <0.0001 c | ||
| Not performed | 57.6 | 52.5 | |
| Performed | 42.4 | 47.5 |
ILC, invasive lobular carcinoma; IDC, invasive ductal carcinoma; ER, estrogen receptor; PR, progesterone receptor; -, negative; +, positive; NOS, not otherwise specified.
aStatistic data only included the patients who had HER2 records after 2010.
bCalculated after exclusion of patients with the unknown or borderline ER/PR status.
c Calculated after exclusion of patients with the unknown groups.