Table 2.
Clinical characteristics of breast cancer patients diagnosed between 2004 and 2016.
| Variable | # (%) |
|---|---|
| ∗Charlson/Deyo comorbidity score | |
| 0 | 2,259,335 (85%) |
| 1 | 325,670 (12%) |
| 2 | 64,289 (2.4%) |
| ≥3 | 22,255 (0.8%) |
| Clinical stage at diagnosis | |
| 0 | 534,244 (21%) |
| I | 1,070,218 (42%) |
| II | 647,845 (25%) |
| III | 220,878 (8.6%) |
| IV | 102,954 (4.0%) |
| Unknown | 95,410 |
| ∗∗Secondary sites in patients diagnosed at stage IV | |
| Bone | 6,934 (68%) |
| Brain | 793 (7.9%) |
| Liver | 2,476 (25%) |
| Lung | 3,072 (31%) |
| Molecular subtype | |
| ER+ or PR+, HER2- | 583,113 (58%) |
| ER+ or PR+, HER2+ | 258,750 (26%) |
| ER- and PR-, HER2- | 104,175 (10%) |
| ER- and PR-, HER2+ | 64,947 (6.4%) |
| Unknown | 1,660,564 |
| Histological subtype | |
| Ductal carcinoma | 1,957,275 (73%) |
| Lobular carcinoma | 402,325 (15%) |
| Adenocarcinoma of mixed types | 1,669 (<0.1%) |
| Rare breast carcinomas | 43,787 (1.6%) |
| Inflammatory invasive carcinoma | 8,803 (0.3%) |
| Other carcinomas | 186,368 (7.0%) |
| Intraductal papillary | 19,330 (0.7%) |
| Papillary neoplasms | 9,536 (0.4%) |
| Epithelial-myoepithelial | 23,751 (0.9%) |
| Fibroepithelial tumors | 3,498 (0.1%) |
| Metaplastic tumors | 11,629 (0.4%) |
| Mesenchymal tumors | 1,758 (<0.1%) |
| Tumors of the nipple | 1,736 (<0.1%) |
| Carcinoid tumors | 64 (<0.1%) |
| Malignant lymphoma | 20 (<0.1%) |
| Grade | |
| Well/moderately differentiated | 1,535,058 (65%) |
| Poorly differentiated | 792,145 (34%) |
| Undifferentiated | 20,949 (0.9%) |
| Unknown | 323,397 |
| Any hormonal therapy | 1,475,279 (87%) |
| Unknown | 978,708 |
| Any chemotherapy | 907,505 (35%) |
| Unknown | 89,559 |
| Any immunotherapy | 94,220 (3.6%) |
| Unknown | 34,964 |
| Any radiation therapy | 1,389,019 (53%) |
| Unknown | 29,641 |
| Type of surgery | |
| None | 194,693 (7.3%) |
| Lumpectomy | 1,459,286 (55%) |
| Mastectomy | 1,007,588 (38%) |
| Unknown | 9,982 |
| Surgical margins | |
| No surgery | 194,693 (7.4%) |
| No residual disease | 2,315,928 (88%) |
| Residual disease | 109,716 (4.2%) |
| Unknown | 51,212 |
∗The Charlson/Deyo index is a weighted score assessing overall comorbidity in patients by cross-referencing these cases to a list of international disease classification (ICD) codes known to be important prognosticators of morbidity and mortality [4]. ∗∗The majority of stage IV patients did not have metastatic site documented, thus these percentages are reflective of the total number of cases for which data were available on this variable (n = 10,131 bone; n = 10,058 brain; n = 10,085 liver; n = 10,046 lung).