Pathologic Complete Response of HER-2 Neu-Positive Invasive Ductal Carcinoma and Ductal Carcinoma In Situ following Neoadjuvant Chemotherapy plus Trastuzumab: A Case Report and Review of Literature

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 HER 2-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.

Increased Malignant Microcalcifications after Neoadjuvant Chemotherapy in Advanced Breast Cancer

In patients with advanced breast cancer, most new calcifications detected on a mammogram after neoadjuvant chemotherapy are benign dystrophic calcifications, but this is not always observed. We present a patient with advanced breast cancer who had paradoxically increased malignant microcalcifications concomitant with primary tumor regression after undergoing neoadjuvant chemotherapy. After the neoadjuvant chemotherapy, the follow-up mammogram revealed that local, fine pleomorphic microcalcifications had markedly increased. Pathologically, these calcifications were ductal carcinoma in situ. We concluded that, in patients with breast cancer undergoing neoadjuvant chemotherapy, newly developed microcalcifications on follow-up mammograms should be carefully evaluated, and any suspicious malignant microcalcifications should be included in surgical excision planning.