Table 1.
Patient characteristics by receipt of surveillance mammography for the first full surveillance year since completion of breast cancer treatment
| Year 1a | |||
|---|---|---|---|
| Surveillance Mammogramb | |||
| No 823 (20.8%) |
Yes 3,142 (79.2%) |
P | |
| Characteristics at Diagnosis of Initial Breast Cancer | |||
| Year of diagnosis | |||
| 1990–1994 | 125 (15.2) | 773 (24.6) | <0.001 |
| 1995–1999 | 152 (18.5) | 962 (30.6) | |
| 2000–2004 | 322 (39.1) | 812 (25.8) | |
| 2005–2008 | 224 (27.2) | 595 (18.9) | |
| Menopausal status | |||
| Peri- or pre-menopausal | 221 (26.9) | 851 (27.1) | 0.89 |
| Post-menopausal | 602 (73.1) | 2291 (72.9) | |
| Race | |||
| Caucasian | 722 (88) | 2780 (88.8) | 0.84 |
| African American | 25 (3.0) | 98 (3.1) | |
| American Indian/Alaska Native | 27 (3.3) | 82 (2.6) | |
| Asian/Pacific Islander | 46 (5.6) | 170 (5.4) | |
| Unknown | 3 | 12 | |
| Education | |||
| High school or less | 86 (24.4) | 323 (23.2) | 0.17 |
| At least some college | 267 (75.6) | 1067 (76.8) | |
| Unknown | 470 | 1752 | |
| Body mass index (kg/m2) | |||
| <18.5 | 17 (2.1) | 45 (1.4) | 0.49 |
| 18.5–24.9 | 277 (33.9) | 1082 (34.5) | |
| 25.0–29.9 | 262 (32.1) | 1030 (32.9) | |
| 30.0–34.9 | 145 (17.7) | 581 (18.5) | |
| 35+ | 116 (14.2) | 395 (12.6) | |
| Unknown | 6 | 9 | |
| Smoking status | |||
| Current | 62 (7.5) | 171 (5.4) | 0.02 |
| Past | 79 (9.6) | 251 (8.0) | |
| Never | 682 (82.9) | 2720 (86.6) | |
| AJCC stage [15] | |||
| I | 477 (58.0) | 2046 (65.1) | <0.001 |
| IIA | 238 (28.9) | 771 (24.5) | |
| IIB | 108 (13.1) | 325 (10.3) | |
| Lymph node status | |||
| Negative | 529 (72.3) | 2174 (77.2) | <0.01 |
| Positive | 203 (27.7) | 641 (22.8) | |
| Unknown | 91 | 327 | |
| ER/PR status | |||
| ER−/PR− | 119 (14.5) | 474 (15.1) | 0.87 |
| ER+/PR− | 69 (8.4) | 288 (9.2) | |
| ER−/PR+ | 14 (1.7) | 43 (1.4) | |
| ER+/PR+ | 579 (70.4) | 2176 (69.3) | |
| ER & PR unknown | 42 (5.1) | 161 (5.1) | |
| Tumor size | |||
| ≤ 2 cm | 580 (70.6) | 2384 (75.9) | <0.01 |
| > 2 cm | 242 (29.4) | 757 (24.1) | |
| Unknown | 1 | 1 | |
| HER2 test result | |||
| Test done | 546 (88.8) | 1404 (76.9) | <0.001 |
| Positive/borderline | 95 (17.4) | 228 (16.2) | 0.09 |
| Negative | 447 (81.9) | 1174 (83.6) | |
| No result | 4 (0.7) | 2 (0.1) | |
| Surgical procedure | |||
| Mastectomy +/− radiation | 376 (45.7) | 1042 (33.2) | <0.001 |
| BCS + radiation | 319 (38.8) | 1759 (56.0) | |
| BCS | 128 (15.6) | 341 (10.9) | |
| Other treatment | |||
| Chemotherapy | 276 (33.5) | 1015 (32.3) | 0.50 |
| Completed course | 240 (87.0) | 901 (88.8) | 0.55 |
| Mode of initial cancer detection | |||
| Screen-detected | 258 (42.4) | 986 (49.9) | <0.01 |
| Screen interval-detected | 80 (13.1) | 247 (12.5) | |
| Diagnostic detected | 253 (41.5) | 674 (34.1) | |
| Diagnostic interval-detected | 18 (3.0) | 68 (3.4) | |
| Unknown | 214 | 1167 | |
| Characteristics Measured Throughout Follow-Up | |||
| Age, yearsc | |||
| Median (IQR) | 64 (30–94) | 64 (31–93) | 0.03 |
| <40 | 29 (3.5) | 67 (2.1) | <0.001 |
| 40–49 | 108 (13.1) | 432 (13.8) | |
| 50–59 | 178 (21.6) | 764 (24.3) | |
| 60–69 | 194 (23.6) | 772 (24.6) | |
| 70–79 | 164 (19.9) | 755 (24.0) | |
| 80+ | 150 (18.2) | 352 (11.2) | |
| Type of provider seenc | |||
| Oncologist only | 16 (1.9) | 69 (2.2) | 0.44 |
| PCP only | 116 (14.1) | 382 (12.2) | |
| Both | 637 (77.4) | 2498 (79.5) | |
| Neither | 54 (6.6) | 193 (6.1) | |
| Charlson co-morbidity index scored | |||
| 0 | 612 (74.4) | 2439 (77.6) | 0.10 |
| 1 | 148 (18.0) | 514 (16.4) | |
| 2+ | 63 (7.7) | 189 (6.0) | |
| Endocrine therapyd,e | 457 (55.5) | 1812 (57.7) | 0.27 |
Abbreviations: SD=standard deviation; IQR=interquartile range; AJCC=American Joint Committee on Cancer; ER=estrogen receptor; PR=progesterone receptor; HER2=human epidermal growth factor receptor 2; BCS=breast conserving surgery; PCP=primary care physician
Year 1 is defined as 7–18 months post-diagnosis to account for the initial treatment period
0.7% of surveillance included breast MRI
Characteristic updated each surveillance year
Time-varying characteristic: variable status was ascertained throughout the entire study period; once subjects met the variable definition for use, they were included in that category and remained there until the end of follow-up.
Endocrine therapy users included women who received a dispensing for tamoxifen and/or aromatase inhibitors for the initial breast cancer between her diagnosis date and before her SBCE date for cases or the end of follow-up for non-cases.