Flow cytometric DNA analysis of invasive carcinomas detected by screening mammography: use of specimen mammography-guided fine-needle aspirates.

Clinical studies of flow cytometric DNA analysis of breast carcinoma are often limited by the lack of fresh tissue samples from smaller, nonpalpable carcinomas. In addition, most studies measuring DNA in the current literature focus on larger palpable masses that may have less relevance to the smaller, nonpalpable lesions. A prospective study of flow cytometric DNA analysis of in vitro specimen mammography-guided fine-needle aspirates (FNAs) of 103 consecutive nonpalpable invasive carcinomas detected by screening mammography was performed to determine efficacy and explore associations with mammographic and pathological features. For 62 (60%) lesions for which DNA analysis on both FNA and standard tissue incision samples was performed, there was excellent (89%) agreement for ploidy determinations (kappa=0.77) and poor agreement for S-phase percentage determinations (kappa=0.23). Specimen mammography-guided FNA analysis detected aneuploidy in 36% of lesions overall, including 34% of 41 lesions for which standard tissue procurement was not possible. Mammographic microcalcifications had a higher aneuploid rate (14 of 28 lesions, 50%) as compared with soft tissue masses (22 of 75 lesions, 29%), P < 0.01. Lobulated masses with indistinct margins had a higher aneuploid rate (5 of 6 lesions, 83%) as compared with more irregular, spiculated masses (7 of 27 lesions, 26%), P < 0.01. The aneuploidy rate was independent of specific histological diagnosis, lesion size, nuclear grade, or nodal or estrogen receptor status. Flow cytometric DNA analysis of mammographic lesion-specific, fresh, cellular FNA samples obtained under specimen mammographic guidance can assess early invasive carcinomas when gross fresh tissue procurement is not possible. This technique could be incorporated into larger clinical follow-up studies to determine the prognostic significance of flow cytometric DNA analysis for these very early breast carcinomas.