The Upgrade Risk of B3 Lesions to (Pre)Invasive Breast Cancer After Diagnosis on Core Needle or Vacuum Assisted Biopsy. A Belgian National Cohort Study

Outcomes of atypical (B3) core biopsy lesions diagnosed across BreastScreen NSW, Australia

INTRODUCTION

Atypical or B3 lesions comprise a heterogeneous group of uncertain malignant potential. B3 lesions diagnosed on core biopsy are usually recommended for diagnostic open biopsy. Identifying factors which could allow conservative management of B3 lesions would be helpful in avoiding unnecessary surgery. The aim of this study was to identify the upgrade rate to malignancy for B3 core biopsy lesions and to compare characteristics of lesions which were malignant and benign at excision.

METHOD

This retrospective study used data from BreastScreen New South Wales (NSW), Australia, of women who were diagnosed with B3 lesions on needle biopsy from 2011 to 2019.

RESULTS

During the study period, 1927 B3 lesions were included. The upgrade rate to malignancy was 26.4%. Of the malignant lesions on excision, 29.6% were invasive and 69.2% were in situ. The rates of upgrade to invasive cancer and DCIS varied substantially with the core biopsy lesion type. Lesions with atypia on core biopsy had significantly higher upgrade rates to malignancy at 34.7% compared to 13.6% for lesions without atypia (p < 0.0001). Lesions with malignant pathology were significantly larger than those with benign pathology (difference = 5.1 mm (95% CI 2.7-7.5 mm), p < 0.001).

CONCLUSIONS

The overall upgrade rate of B3 lesions to malignancy was 26.4%. The majority of the lesions were upgraded to DCIS instead of invasive cancer. Upgrade rates varied by lesion type. Lesions with atypia had significantly higher upgrade rates to cancer compared to lesions without atypia. Malignant lesions were significantly larger than benign lesions.

Could breast multiparametric MRI discriminate between pure ductal carcinoma in situ and microinvasive carcinoma?

BACKGROUND

Ductal carcinoma in situ (DCIS) is often reclassified as invasive cancer in the final pathology report of the surgical specimen. It is of significant clinical relevance to acknowledge the possibility of underestimating invasive disease when utilizing preoperative biopsies for a DCIS diagnosis. In cases where such histologic upgrades occur, it is imperative to consider them in the preoperative planning process, including the potential inclusion of sentinel lymph node biopsy due to the risk of axillary lymph node metastasis.

PURPOSE

To assess the capability of breast multiparametric magnetic resonance imaging (MP-MRI) in differentiating between pure DCIS and microinvasive carcinoma (MIC).

MATERIAL AND METHODS

Between January 2018 and November 2022, this retrospective study enrolled patients with biopsy-proven DCIS who had undergone preoperative breast MP-MRI. We assessed various MP-MRI features, including size, morphology, margins, internal enhancement pattern, extent of disease, presence of peritumoral edema, time-intensity curve value, diffusion restriction, and ADC value. Subsequently, a logistic regression analysis was conducted to explore the association of these features with the pathological outcome.

RESULTS

Of 129 patients with biopsy-proven DCIS, 36 had foci of micro-infiltration on surgical specimens and eight were diagnosed with invasive ductal carcinoma (IDC). The presence of micro-infiltration foci was significantly associated with several MP-MRI features, including tumor size (P <0.001), clustered ring enhancement (P <0.001), segmental distribution (P <0.001), diffusion restriction (P = 0.005), and ADC values <1.3 × 10-3 mm2/s (P = 0.004).

CONCLUSION

Breast MP-MRI has the potential to predict the presence of micro-infiltration foci in biopsy-proven DCIS and may serve as a valuable tool for guiding therapeutic planning.

Upgrade rate to malignancy of uncertain malignant potential breast lesions (B3 lesions) diagnosed on vacuum-assisted biopsy (VAB) in screen detected microcalcifications: Analysis of 366 cases from a single institution

PURPOSE

We retrospectively investigated clinical, radiological, and pathological features of B3 lesions associated with the risk of subsequent upgrade to malignancy.

METHODS

We included consecutive vacuum-assisted biopsies (VABs) performed during 2011-2020 on suspicious microcalcifications not associated with other radiological signs diagnosed as B3 lesions and followed by surgical excision (SE) with definitive histological examination. Multiple logistic regression models were fitted to identify independent predictors of malignancy.

RESULTS

Out of the 366 B3 lesions included, 56 (15.3 %, 95 % CI 11.8-19.4 %) had upgraded to malignancy at SE: of these, 42/366 (11.5 %, 95 % CI 8.4-15.2 %) and 14/366 (3.8 %, 95 % CI 2.1-6.3 %) were in situ and invasive carcinoma, respectively. At univariate analysis, variables positively associated with upgrade to malignancy were age ≥ 60 years (p = 0.008), mixed morphology (p = 0.018), scattered distribution (p = 0,001), extension of microcalcifications > 10 mm (p = 0.001), and mixed B3 lesion (p = 0.017). Among B3 subtypes, the highest rates of upgrade were observed for AIDEP, LCIS/LIN2, FEA + AIDEP, FEA + LCIS/LIN2, and FEA + AIDEP + LCIS/LIN2 (24.6 %, 21.4 %, 25.3 %, 20.0 % and 40.0 % respectively), while FEA and ALH/LIN1 had a lower rates of upgrade (7.5 % and 3.7 %, respectively). Multiple logistic regression analysis confirmed as risk factors older age (p = 0.029), larger extension (p = 0.001) and mixed morphology (p = 0.007) of microcalcifications, AIDEP (p = 0.011) among pure B3 lesions, and FEA + AIDEP (p = 0.001) and FEA + AIDEP + LCIS/LIN2 (p = 0.037) among mixed B3 lesions.

CONCLUSIONS

Based on our findings, vacuum-assisted excision is reasonable as definitive management for FEA and ALH/LIN1, while SE should remain the mainstay of treatment for AIDEP and LCIS/LIN2, whose upgrade rates are too high to safely recommend VAE.