The impact of HER2-directed targeted therapy on HER2-positive DCIS of the breast

Background: In invasive breast cancer, her2 is a well-established negative prognostic factor. however, its significance on the prognosis of ductal carcinoma in situ (DcIs) of the breast is unclear. as a result, the impact of her2-directed therapy on her2-positive DcIs is unknown and is currently the subject of ongoing clinical trials. In this study, we aim to determine the possible impact of her2-directed targeted therapy on survival outcomes for her2-positive DcIs patients. Materials and methods: The National cancer Data Base (NcDB) was used to retrieve patients with biopsy-proven DcIs diagnosed from 2004–2015. patients were divided into two groups based on the adjuvant therapy they received: systemic her2-directed targeted therapy or no systemic therapy. statistics included multivariable logistic regression to determine factors predictive of receiving systemic therapy, Kaplan-Meier analysis to evaluate overall survival (Os), and cox proportional hazards modeling to determine variables associated with Os. results: altogether, 1927 patients met inclusion criteria; 430 (22.3%) received her2-directed targeted therapy; 1497 (77.7%) did not. patients who received her2-directed targeted therapy had a higher 5-year Os compared to patients that did not (97.7% vs. 95.8%, p = 0.043). This survival benefit remained on multivariable analysis. Factors associated with worse Os on multivariable analysis included charlson-Deyo comorbidity score ≥ 2 and no receipt of hormonal therapy. conclusion: In this large study evaluating her2-positive DcIs patients, the receipt of her2-directed targeted therapy was associated with an improvement in Os. The results of currently ongoing clinical trials are needed to confirm this finding.