Impact of core biopsy on the management of screen-detected ductal carcinoma in situ of the breast

Background: Screen‐detected ductal carcinoma in situ (DCIS) usually presents as clinically impalpable microcalcification. Although core biopsy is well established as a diagnostic modality for invasive breast cancers, few reports address its impact on the management of screen‐detected DCIS. We examined the sensitivity of core biopsy in diagnosing screen‐detected DCIS, as well as its role in facilitating one‐step surgery in the community, especially a breast‐conserving approach. Methods: Through the Monash BreastScreen database, we reviewed the management of 148 patients diagnosed with pure DCIS over a 4‐year period. Particular attention was paid to the sensitivity and surgical margin status of 63 patients who underwent initial assessment with core biopsy, compared to patients who underwent excisional biopsy or fine needle aspiration cytology (FNAC). Results: Core specimens in 63 patients yielded positive histology in 57 (90%), allowing for breast‐conserving surgery in 45 and mastectomy in 12. Negative margins were obtained in 73% of those treated by breast‐conserving surgery, compared to 51% negative margins among those who underwent excisional biopsy initially. Overall, 45 of 57 patients with a positive core biopsy histology (79%) underwent one‐step surgery. Those assessed by FNAC had a 48% incidence of non‐diagnostic/benign cytology. Conclusions: Core biopsy facilitates one‐step surgery for screen‐detected DCIS, and potentially reduces the number of surgical procedures. Stereotactic core biopsy for suspicious microcalcifications should replace hookwire‐guided excisional biopsy and FNAC as the diagnostic modality of choice.