演題番号 : P-61
Background There have been severall reports showing different chemosensitivities between primary breast tumors and metastatic sites indicating differences in the immune microenvironment and the aggressively development of biomarkers.
Here, we report a case of breast cancer diagnosed as stage IV due to metastatic lung tumors with different sensitivities to multiple chemotherapeutic interventions.
Case A 51-year-old woman required detail examination of a left breast lump and abnormal lung shadow in a screening chest X-ray. Computed tomography revealed a breast tumor 4.8cm in diameter and lung metastasis. The needle biopsy for the breast tumor led to a diagnosis of invasive ductal cancer with nuclear grade 1, histological grade II, positive ER, negative PgR, negative HER2 and a MIB-I score of 38.5%.
As she initially refused any standard chemotherapy for the breast cancer, endocrine therapy using an aromatase inhibitor was administered.
Three months later, despite shrinkage of metastatic sites, the breast tumor had become enlarged. Additional chemotherapy with paclitaxel failed to reduce both the breast and lung lesions, continuing to develop along with left axillary lymph node involvement.
To control the primary breast lesion, we performed left partial mastectomy and axillary lymph nodes sampling.
After surgery, endocrine therapy and chemotherapy using 17 cycles of epirubicin and cyclophosphamide prior to 7 cycles of eribulin were continued; however, local recurrence of the breast lesion appeared without any increase in the lung metastatic lesions. We performed a second partial mastectomy, with radiation therapy for the left breast and administered a fourth round of chemotherapy.
Conclusion It may be possible that a breast cancer is composed of heterogenetic elements that possess different biological characters leading to different drug sensitivities. In consideration of these differences, it is important to select the appropriated regimens carefully.