Jacky Luiten

Trends in frequency and outcome of high‐risk breast lesions at CNB |55 4 Histologic subtypes of high‐risk breast lesions at CNB and outcome at two‐year follow‐up The most frequently diagnosed histologic subtypes among the 329 high‐risk breast lesions at CNB were papillary lesions (35.3%) and columnar cell lesions/flat epithelial atypia (24.0%), followed by atypical ductal hyperplasia (19.1%) and a combination of high‐risk lesions (11.6%; Table 4.4). Of the 329 high‐risk lesions at CNB, whereof 169 were excised, 14.9% (49/329) proved to be malignant at two‐ year follow‐up. The rate of upgrade to DCIS or invasive carcinoma was highest for CNB yielding atypical ductal hyperplasia (34.9%; 22/63, 18 DCIS and four invasive carcinomas), followed by “other” lesions (30.0%; 3/10, all invasive carcinomas) and papillary lesions (16.4%; 19/116, 14 DCIS and five invasive carcinomas). The 41 malignancies, diagnosed in women with atypical ductal hyperplasia or papillary lesions at CNB, comprised 32 DCIS (of which 20 low grade) and nine invasive cancers (of which four low grade; Table 4.5). The histologic subtypes of high‐risk breast lesions and year of diagnosis at CNB are presented in Table 4.6. No clear increase or decrease was observed in the diagnosis of the different histologic subtypes through the years, except for columnar cell lesions and flat epithelial atypia that were only diagnosed from 2012 onwards. Table 4.4 Histologic subtypes of high‐risk lesions at core needle biopsy and outcome at two‐year follow‐up. Histology n (%) Benign, n (%) Malignant, n (%) Papillary lesion 116 (35.3) 97 (83.6) 19 (16.4) Columnar cell lesion, flat epithelial atypia 79 (24.0) 78 (98.7) 1 (1.3) Atypical ductal hyperplasia 63 (19.1) 41 (65.1) 22 (34.9) Radial scar, complex sclerosing lesion 10 (3.0) 9 (90.0) 1 (10.0) Lobular carcinoma in situ, atypical lobular hyperplasia 13 (4.0) 13 (100) 0 Combination of high‐risk lesions 38 (11.6) 35 (92.1) 3 (7.9) Other 10 (3.0) 7 (70.0) 3 (30.0) Total 329 280 (85.1) 49 (14.9) Table 4.5 Type and grading of malignancy in women with high‐risk lesions at core needle biopsy. Histology at percutaneous biopsy, n Ductal carcinoma in‐situ Invasive cancer low intermediate high I II III Papillary lesion 10 3 1 2 1 2 Columnar cell lesion, flat epithelial atypia 1 Atypical ductal hyperplasia 10 8 2 2 Radial scar, complex sclerosing lesion 1 Combination of high‐risk lesions 3 Other 1 2 Total 24 11 1 6 3 4