Atypical ductal hyperplasia: improved accuracy with the 11-gauge vacuum-assisted versus the 14-gauge core biopsy needle.

BACKGROUND

Percutaneous stereotactic core needle biopsy (CNB) has become the primary diagnostic modality for evaluating nonpalpable, mammographically detected breast lesions. Atypical ductal hyperplasia (ADH) uncovered by CNB confers a significant risk of harboring an occult malignancy in the excisional biopsy specimen; therefore, we sought to determine the benefits of upsizing biopsy needles from 14- to 11-gauge.

METHODS

Patients with isolated ADH diagnosed by CNB were included for analysis in this retrospective review. Mammographic description, number of needle passes, pathology results, and follow-up data were analyzed and compared to our previously published institutional results with the 14-gauge needle.

RESULTS

From June 1996 until July 2006, 4,579 CNBs were performed at our tertiary level medical facility. Seventy eight of 88 patients (89%) diagnosed with ADH on CNB with an 11-gauge vacuum-assisted needle underwent open surgical excision. Of these patients, nine (11%) were upgraded to ductal carcinoma in-situ (DCIS) while five (6%) had invasive cancer (IC), giving a total underestimation rate of 17%. These results differ from our previously published series of 14-gauge CNB which revealed an underestimation rate of 36%. Mean number of passes obtained at time of biopsy, mean age of patients, and characteristic radiographic abnormalities were similar for malignant and benign diagnoses.

CONCLUSION

11-gauge CNB technique reduces sampling error and improves accuracy, but does not eliminate the risk of missing an underlying malignancy. Surgical excision of ADH identified by CNB is required for definitive diagnosis.