Table 2.
Characteristics of female Medicare beneficiaries diagnosed with breast cancer in the linked BCSC-Medicare data from 2000–2006 (N=3316)
| All cancer cases | No comorbidities (N = 350) | Stable a comorbidities (N = 2,018) | Unstable b only or both stable and unstable co-morbidities (N = 948) | P | |||||
|---|---|---|---|---|---|---|---|---|---|
| n | (%) | n | (%) | n | (%) | n | (%) | ||
| Age at diagnosis | <0.001 | ||||||||
| 67–74 | 1516 | (45.7) | 192 | (54.9) | 942 | (46.7) | 382 | (40.3) | |
| 75–79 | 918 | (27.7) | 95 | (27.1) | 538 | (26.7) | 285 | (30.1) | |
| 80–84 | 562 | (16.9) | 42 | (12) | 346 | (17.1) | 174 | (18.4) | |
| ≥85 | 320 | (9.7) | 21 | (6) | 192 | (9.5) | 107 | (11.3) | |
| Race/Ethnicity | 0.0159 | ||||||||
| White | 2628 | (79.3) | 296 | (84.6) | 1610 | (79.8) | 722 | (76.2) | |
| Black | 270 | (8.1) | 19 | (5.4) | 161 | (8) | 90 | (9.5) | |
| Other/Unknownc | 418 | (12.6) | 35 | (10.0) | 247 | (12.2) | 136 | (14.3) | |
| Number of comorbid conditions | 0.001 | ||||||||
| None (0) | 350 | (10.6) | 350 | (100) | - | - | |||
| 1 | 553 | (16.7) | - | 545 | (27) | 55 | (5.8) | ||
| 2 | 580 | (17.5) | - | 533 | (26.4) | ||||
| 3 | 506 | (15.3) | - | 396 | (19.6) | 110 | (11.6) | ||
| 4 | 354 | (10.7) | - | 244 | (12.1) | 110 | (11.6) | ||
| 5 | 276 | (8.3) | - | 149 | (7.4) | 127 | (13.4) | ||
| >5 | 697 | (21) | - | 151 | (7.5) | 546 | (57.6) | ||
| Mammography use (time between mammography examinations)d | <0.001 | ||||||||
| 4–18 months | 1898 | (63.0) | 164 | (54.5) | 1240 | (66.7) | 494 | (58.1) | |
| 19–30 months | 425 | (14.1) | 42 | (14.0) | 259 | (13.9) | 124 | (14.6) | |
| 31–42 months | 157 | (5.2) | 14 | (4.7) | 91 | (4.9) | 52 | (6.1) | |
| >42 months or first screen e | 249 | (8.3) | 33 | (11.0) | 138 | (7.4) | 78 | (9.2) | |
| >42 months or first diagnosticf | 282 | (9.4) | 48 | (15.9) | 132 | (7.1) | 102 | (12.0) | |
| Tumor characteristics | 0.479 | ||||||||
| In Situ | 501 | (15.1) | 49 | (14.0) | 317 | (15.7) | 135 | (14.2) | |
| Invasive | 2814 | (84.9) | 301 | (86.0) | 1700 | (84.3) | 813 | (85.8) | |
| Stage g | 0.001 | ||||||||
| Stage I | 1458 | (59.8) | 138 | (53.1) | 922 | (61.9) | 398 | (57.6) | |
| Stage IIA | 519 | (21.3) | 69 | (26.5) | 308 | (20.7) | 142 | (20.5) | |
| Stage IIB | 195 | (8.0) | 20 | (7.7) | 97 | (6.5) | 78 | (11.3) | |
| Stage III, IV | 268 | (11.0) | 33 | (12.7) | 162 | (10.9) | 73 | (10.6) | |
| Tumor size | 0.028 | ||||||||
| <10 mm | 854 | (29.2) | 81 | (26.8) | 540 | (30.2) | 233 | (27.9) | |
| 11–15 mm | 860 | (29.4) | 86 | (28.5) | 549 | (30.7) | 225 | (26.9) | |
| >=16 mm | 1210 | (41.2) | 135 | (44.7) | 697 | (39) | 378 | (45.2) | |
| Tumor grade | 0.034 | ||||||||
| Well differentiated | 610 | (23.0) | 81 | (29.9) | 370 | (22.8) | 159 | (20.9) | |
| Moderately differentiated | 1233 | (46.4) | 112 | (41.3) | 768 | (47.3) | 353 | (46.4) | |
| Poorly differentiated/Undifferentiated | 812 | (30.6) | 78 | (28.8) | 485 | (29.9) | 248 | (32.6) | |
| Estrogen Receptor Status | 0.761 | ||||||||
| Positive | 1964 | (84.5) | 202 | (85.6) | 1194 | (84.1) | 568 | (85.0) | |
| Negative | 360 | (15.5) | 34 | (14.4) | 226 | (15.9) | 100 | (15.0) | |
Stable comorbidities are defined as age-related conditions with no influence on predicted 5 year mortality. Examples include arthritis, osteoporosis, depression, diabetes, thyroid disorders, stable coronary artery disease, and peptic ulcer disease (Appendix 1).
Unstable comorbidities are defined as life threatening or difficult to control with less than 5 year predicted mortality. Examples include severe heart failure, end-stage pulmonary disease, end-stage liver disease, renal disease, and diabetes with complications (Appendix 1).
Groups collapsed due to small cell sizes.
Mammography use was categorized according to type of examination and time between mammography examinations. Time to prior mammogram was calculated using last mammogram before cancer diagnosis for women with a cancer diagnosis and a randomly selected mammogram for women with no cancer diagnosis.
>42 months or first screen is defined as a screening mammogram with no prior mammogram within 42 months.
>42 months years or first diagnostic is defined as a diagnostic mammogram with no prior within 42 months.
Breast cancer stage at diagnosis is classified on TNM staging system (tumor, node, and metastasis) which is based on the criteria of the American Joint Commission. Stage distribution was computed among invasive tumors only.