E. Shelley Hwang

PURPOSE: Re-excision for close margins in patients undergoing breast-conserving surgery (BCS) for ductal carcinoma in situ (DCIS) aims to reduce recurrence rates. The current recommended margin width of ≥2 mm is based on study-level data. Using a multicenter cohort, we aimed to determine whether patient-level analysis of margin width support that negative margins <2 mm confer higher recurrence rates than margins ≥2 mm. METHODS: We conducted a retrospective, observational cohort study of women diagnosed with DCIS between 2008 and 2015 treated with BCS. Patient, diagnosis, treatment, and outcome data were abstracted by local registrars and from a national database. Final margin width was categorized as positive (tumor on ink), 0.01-0.9 mm, 1.0-1.9 mm, or ≥2 mm. The primary outcome was ipsilateral recurrence. The Kaplan-Meier method and multivariable Cox proportional hazards models were used to estimate the effect of margin width on recurrence risk. RESULTS: Among 11,156 women in the final cohort, 72.2% (n = 8,059) received BCS + radiotherapy and 27.8% (n = 3,097) received BCS alone. Median age at diagnosis was 61 years; median follow-up was 66.6 months. A total of 445 (4%) women experienced a recurrence during follow-up. In a multivariable adjusted analysis, there was no significant difference in recurrence risk between the negative margin groups both in patients who had either BCS with radiation or BCS alone. In subgroup analyses by age, race, hormone receptor status, grade, size, endocrine therapy, and radiation treatment, only the age <50 years subgroup showed a significant difference in recurrence risk between narrow (0.01-1.9 mm) and wide (≥2 mm) margins. CONCLUSION: In this multivariable analysis of 11,156 patients, negative margins <2 mm were not associated with a higher local recurrence risk compared with margins ≥2 mm except in patients younger than 50 years at diagnosis.

Background: Ductal carcinoma in situ (DCIS) is a noninvasive breast lesion with variable risk of progression to invasive breast cancer (IBC). Current transcription and cell marker investigations suggest ECM decreases in later events but are limited in details of ECM proteomic composition, including post-translational modifications. We investigated whether the extracellular matrix (ECM) proteome alters with later breast events of DCIS or IBC. Methods: ECM-targeted mass spectrometry imaging and liquid chromatography–tandem mass spectrometry (LC–MS/MS) were applied to ten tissue microarrays from the Resource of Archival Human Breast Tissue cohort (RAHBT). Primary DCIS specimens (n=136) were analyzed in relation to later events of DCIS (n=40) or IBC(n=30), with a mean follow-up of 192.1 months 95% CI [179.1,205.1]. Statistical modeling, survival analyses, and exploratory machine learning approaches were used to identify ECM peptide signatures associated with later events. Results: Distinct ECM peptide profiles were associated with later events of DCIS or IBC. Fifteen peptides derived from fibrillar collagens (COL1A1, COL1A2, COL3A1) and elastin, showed significantly reduced abundance in patients who developed IBC. Lower expression of specific collagen peptides associated with overall 19.9% 95% CI [17.92, 21.81] decreased disease-free survival for IBC. Lower expression of these peptides was significantly associated with reduced disease-free survival (age-adjusted hazard ratio [HR] = 2.45, 95% CI: 2.33–2.57; P < 0.05). Patient-matched samples of primary DCIS, later DCIS, and later invasive breast cancer further demonstrated reduction in ECM peptide detection. Exploratory predictive modeling from patient-matched samples achieved high performance (AUROC >0.98, accuracy >93%) in distinguishing primary from later events. Following prior work in the RAHBT cohort, reduction of certain collagen peptides was also observed in primary DCIS samples from higher risk patient groups. Conclusions: ECM proteomic remodeling, particularly decreases of specific collagen domains, is strongly associated with later events of DCIS and IBC. These findings highlight ECM proteome as a critical regulator of breast cancer emergence with potential as a prognosticator of risk stratification to guide clinical management of DCIS.

Supplementary Table S5 Adverse effects observed in Phase 1b

Supplementary Figure S1 related to Figure 1 (A) CSF-1 levels in serum from phase 1b comparing C1D1, C1D2, and C2D1 at concentrations of PLX shown where each line reflects an individual patient, and colors indicate clinical response of 28 patients: No data on response (ND); progressive disease (PD); stable disease (SD); partial response (PR); deceased (DC).

Supplementary Table S2 Representativeness of Study Participants

Supplementary Figure S3 related to Figure 3 Immune infiltrate changes following PLX and PTX combination therapy.

Supplementary Table S6 - Enrollment and clinical response in Phase 2

Purpose:Significant correlations exist between the presence of intratumoral macrophages, tumor progression, and poor outcomes in triple-negative breast cancer (TNBC) with limited therapeutic options available for advanced-stage disease. Preclinical studies revealed that inhibition of myelomonocytic colony-stimulating factor 1 (CSF1) or its receptor (CSF1R) plus cytotoxic chemotherapy decreased primary tumor growth kinetics and pulmonary metastases by CD8+ T cell–dependent mechanisms. This translational study evaluated CSF1R inhibition combined with eribulin in metastatic TNBC and explored rational preclinical combination strategies with PD-1/PD-L1 blockade based on clinical immune correlate analyses.Patients and Methods:A nonrandomized, open-label phase Ib/2 trial (NCT01596751) evaluated pexidartinib (PLX3397), a CSF1R inhibitor (CSF1Ri), plus eribulin mesylate in heavily pretreated individuals with metastatic TNBC. Clinical efficacy was assessed alongside peripheral blood correlates. Preclinical studies in transgenic mammary adenocarcinoma models examined biomarker-driven therapy combinations.Results:The 12-week progression-free survival rate was 36% (95% confidence interval, 22.2%–58.4%), with 44.8% of patients achieving clinical benefit; a subset experienced disease control beyond 6 months. Patients with partial response or stable disease demonstrated increased baseline leukocyte activation, including enrichment of CD8+ and CD4+ memory T cells and increased PD-1 expression on CD4+ T cells. In preclinical studies, CSF1Ri expanded the therapeutic index of PD-1 blockade, yielding transient tumor regression in ∼60% of mice and a transient expansion of effector and resident memory T cells.Conclusions:These clinical and preclinical findings provide rationale for therapies to increase the therapeutic index of αPD-1 therapy by diminishing the presence of T cell–suppressive myelomonocytic cells to improve outcomes for patients with refractory disease.