Pathological features of invasive lobular carcinomas compared with grade-matched invasive ductal carcinoma of no special type
| Variables | Invasive ductal carcinoma of no special type (n=820 (65.8%)) | Invasive lobular carcinomas (n=426 (34.2%)) | p Value |
| Operation type: | |||
| Mastectomy (vs wide local excision) | 466 (56.8%) | 254 (59.6%) | 0.464 |
| Axillary-node surgery: | |||
| Axillary sample (vs clearance) | 476 (58.0%) | 245 (57.4%) | 0.661 |
| Histological grade 1 | 55 (6.7%) | 18 (4.2%) | 0.130 |
| 2 | 692 (84.4%) | 376 (88.3%) | |
| 3 | 73 (8.9%) | 32 (7.5%) | |
| Mean size (mm) | 17.1 | 24.4 | <0.0001 |
| Vascular invasion | 211 (27.7%) | 39 (13.5%) | <0.001 |
| Oestrogen receptor (positive) | 311 (84%) | 492 (72%) | <0.001 |
| Progesterone receptor (positive) | 232 (65%) | 353 (58%) | 0.024 |
| Lymph-node stage | |||
| Nottingham Prognostic Index stage 1 | 549 (67.0%) | 259 (60.8%) | <0.0001 |
| 2 | 234 (28.5%) | 111 (26.1%) | |
| 3 | 37 (4.5%) | 56 (13.1%) | |
| Tumour–node–metastasis stage pN0 | 549 (67.0%) | 259 (60.8%) | <0.0001 |
| pN1 | 234 (28.5%) | 111 (26.1%) | |
| pN2 | 35 (4.3%) | 38 (8.9%) | |
| pN3 | 2 (0.2%) | 18 (4.2%) | |
| Total no of nodes removed (mean) | 5.35 | 6.20 | 0.043 |
| Positive nodes* | |||
| Mean no of positive nodes | 2.12 | 4.20 | <0.0001 |
| Axillary lymph-node ratio (positive nodes/total no of nodes removed), median (range) | 0.25 (0.04–1.0) | 0.37 (0.08–1.0) | <0.001 |
↵* When the analysis was restricted to cases with four or more axillary lymph nodes sampled, the mean number of positive nodes in invasive lobular carcinomas was 4.7 (±SD 5.8; range 1–38) compared with a mean of 2.3 nodes positive (±SD 2.2; range 1–20) in invasive ductal carcinoma.