The role and histological classification of needle core biopsy in comparison with fine needle aspiration cytology in the preoperative assessment of impalpable breast lesions

Aims-To investigate the role of needle core biopsy (NCB) in the preoperativ e assessment of impalpable breast lesions, mainly derived from the NHS Brea st Screening Programme (NHSBSP) and to assess our own modifications to a su ggested system for the classification of breast NCBs. Methods-The NCB, fine needle aspiration cytology (FNAC), and radiology scor es from 298 women with non-palpable breast lesions presenting between Janua ry 1997 and December 1998, together with the open biopsy results (where ava ilable) were collated and analysed. Results-The mean follow up period was 15.8 months (range, 5-28). The 298 NC B specimens were categorised as follows: unsatisfactory/non-representative (El; n = 61; 20.5%), benign but uncertain whether representative (B2r; n = 52; 17.4%), benign (B2; n = 103; 34.6%), lesions possibly associated with m alignancy but essentially benign (B3a; n = 9; 3.0%), atypical epithelial pr oliferations (B3b; n = 10; 3.4%), suspicious of malignancy (B4; n = 7; 2.3% ), and malignant (B5; n = 56; 18.7%). Excision biopsy was performed in 43 c ases within the B1 (n = 19), B2r (n = 8), B2 (n = 8), and the B3a (n = 8; d ata unavailable in one case) categories, revealing malignancy in 18 (42.8%) cases and in 65 cases within the B3b, B4, and B5 categories, revealing mal ignancy in 64 cases (98.5%). The sensitivity of NCB for malignancy was 87.7 %, with a specificity and positive predictive value of 99.3% and 98.5%, res pectively. FNAC had an inadequacy rate of 58.7%, a complete sensitivity of 34.5% and a specificity of 47.6%. Conclusions-This study confirms the value of NCB in the preoperative assess ment of impalpable breast lesions. Two new categories are suggested for the NCB classification; category B2r for benign breast tissue where representa tiveness is uncertain, and the subdivision of category B3 into B3a for beni gn lesions potentially associated with malignancy (for example, radial scar s and intraduct papillomas) and B3b for more worrisome atypical epithelial proliferations. These will aid the accurate audit of NCB and identify more clearly the intellectual pathway leading to a particular assessment.