Ductal Carcinoma In Situ with Microinvasion on Core Biopsy: Evaluating Tumor Upstaging Rate, Lymph Node Metastasis Rate, and Associated Predictive Variables.

INTRODUCTION: The role of sentinel lymph node biopsy (SLNB) when ductal carcinoma in situ with microinvasion (DCISM) is identified on core biopsy is unclear. OBJECTIVE: Our aim was to assess the upstage rate to invasive cancer and axillary lymph node metastasis in patients diagnosed with DCISM, and whether predictive variables could be identified that may help inform who would most likely benefit from a surgical axillary evaluation. METHODS: We performed a retrospective review of 70 patients diagnosed with DCISM on core biopsy. Patients with concomitant or prior invasive cancer were excluded. Demographic, clinical, radiographic, histologic, and treatment data were collected. Fisher's exact test and univariable and multivariable logistic regression were performed to identify variables that may be associated with tumor upstaging and nodal metastasis. Time-to-event distributions were summarized using the Kaplan-Meier method. RESULTS: On final surgical pathology, 49 patients (70%) had a final diagnosis of DCISM or T1mi cancer, whereas 21 patients (30%) were upstaged to measurable invasive cancer (> 1 mm). One of 49 patients (2%) with DCISM on final pathology and 4 of 21 patients (19%) with measurable invasive cancer showed sentinel lymph node metastases. CONCLUSION: Although the upstage rate to measurable invasive cancer in our cohort of patients with DCISM on core biopsy was 30%, findings of a positive SLNB remain low at 7%. No predictive variables were identified to inform whether the routine practice of SLNB may be omitted in some patients with DCISM.

Rate of radial scars by core biopsy and upgrading to malignancy or high-risk lesions before and after introduction of digital breast tomosynthesis.

PURPOSE: Radial scars (RS) commonly present mammographically as architectural distortions, but these lesions may be associated with non-invasive and invasive breast cancer. Digital breast tomosynthesis (DBT) has resulted in higher detection rates of architectural distortion particularly in patients with dense breast tissue. We hypothesized that rates of clinically relevant lesions confirmed surgically would be lower in patients who received DBT imaging compared with those who received standard digital breast imaging. METHODS: We performed a retrospective review of 223 patients diagnosed with pure RS by core biopsy and surgical excision before and after DBT was introduced. The rate of upgrading to malignancy or high-risk lesion was evaluated. Demographics, biopsy type, and histologic data were analyzed. Univariable logistic regression analysis was used to identify variables that may be associated with upgrading. RESULTS: The rate of identifying RS increased from 0.04-.13% (P < 0.0001) with DBT imaging. The upgrade rate on surgical specimen to invasive or non-invasive cancer was similar before and after DBT; 6% versus 3%, as were findings of a high-risk lesion; 12% versus 22%. No predictive factors were identified for patients upgraded to malignant neoplasms or high-risk lesions. CONCLUSIONS: The likelihood of identifying RS has increased with DBT imaging, but rates of upgrading to a malignant neoplasm or high-risk lesion were similar to those before DBT. Although the rate of upgrading to malignancy after DBT was low, an excisional biopsy should be considered as 22% of patients were upgraded to high-risk lesions. These patients are candidates for chemoprevention and/or high-risk surveillance.