Table 2.
Summary of terminal duct lobular unit involution measures by age and separated by menopausal status
| Premenopausal women (n = 1369) | No. (%) | THLU count* (n = 1369) | No. (%) | Median THLU span (n = 949) | Median category of acini counts/THLU† (n = 949) | |||
|---|---|---|---|---|---|---|---|---|
| Category | Median | Range | Median | Range | Median | Range | ||
| Age, y | ||||||||
| <30 | 452 (33.0) | 5 | 0–62 | 322 (33.9) | 373.25 | 118–1000 | 2 | 1–5 |
| 30–39 | 410 (29.9) | 5 | 0–70 | 286 (30.1) | 338 | 84–1143 | 2 | 1–5 |
| 40–49 | 395 (28.9) | 3 | 0–57 | 272 (28.7) | 319.25 | 111.5–950 | 1.5 | 1–5 |
| 50–58 | 112 (8.2) | 2 | 0–46 | 69 (7.3) | 295 | 106–2150 | 1 | 1–5 |
| Postmenopausal women (n = 569) | No. (%) | TDLU count* (n = 569) | No. (%) | Median TDLU span (n = 330) | Median category of acini counts/TDLU † (n = 330) | |||
| Category | Median | Range | Median | Range | Median | Range | ||
| Age, y | ||||||||
| <50 | 83 (14.6) | 3 | 0–31 | 51 (15.5) | 278 | 117.5–1097.5 | 1 | 1–5 |
| 50–59 | 264 (46.4) | 2 | 0–34 | 163 (49.4) | 257.5 | 53–1375 | 1 | 1–5 |
| 60–75 | 222 (39.0) | 1 | 0–35 | 116 (35.2) | 237.5 | 79.5–869 | 1 | 1–5 |
* Terminal duct lobular unit (TDLU) count is highly correlated with TDLU density/mm2 (Spearman rho = 0.98) reflecting the standardized tissue collection procedures of the Susan G. Komen Tissue Bank at the IU Simon Cancer Center. The median tissue area = 34.51mm2 (SD = 17.57 mm2). TDLU = terminal duct lobular unit.
† The number of acini/TDLU was recorded in categories (1 = <=10, 2 = 11–20, 3 = 21–30, 4 = 31–50, and 5 = 51+). We computed the median acini category value and median TDLU span for each woman with TDLUs observed.