Is zero underestimation feasible? Extended Vacuum-Assisted Breast Biopsy in solid lesions - a blind study.

BACKGROUND

Vacuum-Assisted Breast Biopsy (VABB) is effective for the preoperative diagnosis of non-palpable mammographic solid lesions. The main disadvantage is underestimation, which might render the management of atypical ductal hyperplasia (ADH), and ductal carcinoma in situ (DCIS) difficult. This study aims to develop and assess a modified way of performing VABB.

PATIENTS AND METHODS

A total of 107 women with non-palpable mammographic breast solid tumors BI-RADS 3 and 4 underwent VABB with 11G, on the stereotactic Fischer's table. 54 women were allocated to the recommended protocol and 24 cores were obtained according to the consensus meeting in Nordesterdt (1 offset-main target in the middle of the lesion and one offset inside). 53 women were randomly allocated to the extended protocol and 96 cores were excised (one offset-main target in the middle of the lesion and 7 peripheral offsets). A preoperative diagnosis was established. Women with a preoperative diagnosis of precursor/preinvasive/invasive lesion underwent open surgery. A second pathologist, blind to the preoperative results and to the protocol made the postoperative diagnosis. The percentage of the surface excised via VABB was retrospectively calculated on the mammogram. The discrepancy between preoperative and postoperative diagnoses along with the protocol adopted and the volume removed were evaluated by Fisher's exact test and Mann-Whitney-Wilcoxon test, respectively.

RESULTS

Irrespectively of the protocol adopted, 82.2% of the lesions were benign. 14.0% of the lesions were malignancies (5.1% of BI-RADS 3, 5.3% of BI-RADS 4A, 25% of BI-RADS 4B, and 83.3% of BI-RADS 4C lesions). 3.7% of the biopsies were precursor lesions. There was no evidence of underestimation in either protocols. In the standard protocol, the preoperative/postoperative diagnoses were identical. In the extended protocol, the postoperative diagnosis was less severe than the preoperative in 55.5% of cases (55.5% vs. 0%, p = 0.029), and preoperative ADH was totally removed. The phenomenon of discrepancy between diagnoses was associated with larger volume removed (8.20 +/- 1.10 vs. 3.32 +/- 3.50 cm3, p = 0.037) and higher removed percentage of the lesion (97.83 +/- 4.86% vs. 74.34 +/- 23.43%, p = 0.024)

CONCLUSION

The extended protocol seems to totally excise precursor lesions, with minimal underestimation. This might possibly point to a modified management of ADH lesions.