The expression of hormone receptors (estrogen and progesterone) and human epidermal growth factor receptor-2 (HER2) has been used for both therapeutic and prognostic purposes in the management of breast cancer. The presence of a discordant receptor status complicates the approach to treatment in patients with synchronous bilateral breast cancer. We describe the case of a 45-year-old female with synchronous bilateral breast cancer with a triple-negative tumor and a contralateral HER2-positive tumor and discussed the impact of this on the approach to therapeutic management.

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e19059 Background: Hematopoietic stem cell transplantation (HSCT) is a core component of the standard of care for many patients with leukemia, lymphoma and multiple myeloma. We aim to evaluate the trend in HSCT for patients with leukemia, lymphoma, and myeloma in the United States. Methods: This is a retrospective cross-sectional study of transplant activity performed at HSC transplant centers in the United States from January 2016 to December 2020 based on the reports submitted to the Center for International Bone Marrow Transplant Research (CIBMTR). CIBMTR transplant data were evaluated for trends in number of transplant, donor type, cell source and age of patients with leukemia, lymphoma and myeloma who received stem cell transplantation. Results: A total of 87,723 patients with leukemia, lymphoma and myeloma received stem cell transplantation during the study period. The transplant recipients were 0-17 years (4.1%), 18-64 years (66.7%) and ≥ 65 years (29.2%). Indication for the transplantations were multiple myeloma (44.7%), Hodgkin lymphoma (5.5%), non-Hodgkin lymphoma (19.4%), acute lymphoblastic leukemia (8%), acute myeloid leukemia (19.4%), chronic myeloid leukemia (1.4%) and other leukemias (1.5%). Donor types were autologous (64.8%), allogeneic related (16.3%) and unrelated (18.9%). Peripheral blood was the most common cell source (91.6%), followed by bone marrow (6.2%) and cord blood (2.2%). Eighty six percent of all cord blood transplantation were performed for acute leukemias. The total number of transplantation trended up across all disease categories from 2016 to 2019 but slightly declined in 2020. Allogeneic HCT for non-Hodgkin lymphoma and multiple myeloma declined by 11% and 50% respectively between 2016 and 2020. Conclusions: The COVID pandemic has minimal impact on HSCT in the US. HSCT is more commonly performed for myeloma than for patients with lymphoma or leukemia. Most transplants are autologous with peripheral blood as the cell source. There is a progressive decline in the use of allogeneic HSCT for myeloma and non-Hodgkin lymphoma possibly due to emerging novel therapies. [Table: see text]