Table 4.
Characteristics and outcomes of patients with DCIS by diabetes status and metformin use status at DCIS diagnosis
| Without diabetes | With diabetes, receiving metformin | With diabetes, Not receiving metformin | P, without versus with diabetes | P, receiving metformin versus not | |
|---|---|---|---|---|---|
| Number of patients | 1,737 (93.6) | 62 (3.3) | 56 (3.0) | ||
| BMI | |||||
| Normal or underweight (BMI <25 kg/m2) | 816 (47.0) | 5 (8.1) | 10 (17.9) | ||
| Overweight (BMI 25 to <30 kg/m2) | 483 (27.8) | 12 (19.4) | 15 (26.8) | ||
| Obese (BMI ≥ 30 kg/m2) | 438 (25.2) | 45 (72.6) | 31 (55.4) | <0.001 | 0.117 |
| Race | |||||
| White | 1,310 (75.4) | 30 (48.4) | 32 (57.1) | ||
| African American | 171 (9.8) | 19 (30.7) | 13 (23.2) | ||
| Hispanic | 147 (8.5) | 9 (14.5) | 6 (10.7) | ||
| Asian/Pacific Islander | 90 (5.2) | 4 (6.5) | 5 (8.9) | ||
| Other | 19 (1.0) | 0 (0) | 0 (0) | <0.001 | 0.659 |
| Menopausal status | |||||
| Premenopausal | 510 (29.4) | 8 (12.9) | 7 (12.5) | ||
| Postmenopausal | 1,224 (70.6) | 54 (87.1) | 49 (87.5) | <0.001 | 0.948 |
| Hormonal replacement therapy use | 539 (31.0) | 18 (29.0) | 19 (33.9) | 0.941 | 0.567 |
| Age, median (range) | 54 years (18–89) | 61 years (37–79) | 58.5 years (11–82) | <0.001 | 0.736 |
| Largest recorded mammographic dimension, median (range) | 2.5 cm (0.05–18) | 2.4 cm (0.3–11) | 2.1 cm (0.07–10) | 0.804 | 0.901 |
| Largest recorded pathologic size, median (range) | 1.2 cm (0.01–19) | 1.5 cm (0.09–17) | 1.7 cm (0.05–12) | 0.012 | 0.342 |
| Nuclear grade | |||||
| I | 163 (9.6) | 6 (10.0) | 7 (13.0) | ||
| II or III | 1,541 (90.4) | 54 (90.0) | 47 (87.0) | 0.521 | 0.619 |
| Necrosis present | 672 (38.7) | 30 (48.4) | 21 (37.5) | 0.329 | 0.233 |
| ER status | |||||
| Positive | 814 (80.0) | 35 (85.4) | 29 (80.6) | ||
| Negative | 204 (20.0) | 6 (14.6) | 7 (19.4) | 0.503 | 0.574 |
| Adjuvant tamoxifen (in all patients) | 631 (36.3) | 28 (45.2) | 20 (35.7) | 0.342 | 0.297 |
| Adjuvant radiotherapy (in patients who underwent BCS) | 799 (78.2) | 33 (89.2) | 26 (89.7) | 0.031 | 0.951 |
| Local–regional recurrence (in patients who underwent BCS) | |||||
| Total | 44 (4.3) | 1 (2.7) | 0 (0) | 0.605 | 0.376 |
| DCIS | 26 (59.1) | 1 (100.0) | 0 (0) | ||
| Invasive | 18 (40.9) | 0 (0) | 0 (0) | ||
| Development of contralateral breast cancera | |||||
| Total | 61 (4.3) | 0 (0) | 3 (6.0) | 0.856 | 0.145 |
| DCIS | 30 (48.4) | 0 (0) | 2 (66.7) | ||
| Invasive | 32 (51.6) | 0 (0) | 1 (33.3) | ||
NA not applicable (a test was not possible because no failures occurred), BCS breast-conserving surgery
a
Excludes patients who had contralateral prophylactic mastectomy, bilateral breast cancer at diagnosis, and history of contralateral breast cancer