Background: Stereotactic large-core needle biopsy (SLCNB) is a minimally invasive method for histological diagnosis of nonpalpable breast disease. We studied differences in cancer prevalence between a group of women referred through the national screening program and a non-screening group, and assessed whether the validity of SLCNB differed between these groups.
Methods: A group of non-selective, consecutive patients presenting with a nonpalpable mammographic lesion, who participated in a recently conducted multicenter study regarding the accuracy of SLCNB in The Netherlands, were the basis for this study. Prevalence of carcinoma, predictive value of a benign diagnosis, sensitivity, and specificity rate of SLCNB were compared between the two groups.
Results: Of the 1029 lesions in 972 patients included, 858 were evaluable. In 850/858 lesions (99.1%) the reason for referral was clear. The prevalence of cancer in the screening group (n = 511 lesions) was 64.0% (95%CI 59.8-68.2), versus 49.6% in the non-screening group (n = 339) (95%CI 44.2-54.9). Respective predictive values of a benign diagnosis on SLCNB were 97.0 versus 94.8% (non-significant). The sensitivity rates of SLCNB were 98.5% (screening; 95%CI 96.5-99.5) versus 95.2% (non-screening; 95%CI 90.8-97.9). Specificity rates were 97.8 (95%CI 94.5-99.4) and 99.4% (95%CI 96.8-100), respectively.
Conclusion: Despite a significant difference in the prevalence of carcinoma, the accuracy of SLCNB did not show a statistically significant difference between both patient groups. Therefore, SLCNB appears accurate in diagnosing nonpalpable breast lesions both in screening and non-screening patient groups.