(1) Micrometastasis in sentinel lymph node (SLN)
Sentinel node biopsy (SNB) for the diagnosis of early stage breast cancer has been established as an excellent surgical and staging procedure to enhance the detection of minimal lymph node involvement such as micrometastases (1). To date, the routine single (maximal) sectioned pathological analysis using a hematoxylin and eosin stained section without immunohistochemistry for SLNs has resulted in the low identification rate of micrometastasis. From 2007, multisection analysis led to the significantly increased detection of micrometastases in SLNs. This has led to new questions regarding the choice of treatment for micrometastasis.
(2) Triple-negative breast cancer
Triple-negative breast cancers are defined by a lack of expression of estrogen, progesterone, and HER2 receptors. A retrospective analysis revealed that this subgroup accounted for 17% of all types of breast cancer, and that they were associated with aggressive behavior and significantly poor prognosis because this subgroup was unlikely to benefit from the currently available targeted systemic therapy. However, although apocrine carcinoma often showed a triple negative phenotype, its prognosis was similar to that of invasive ductal carcinoma (IDC) (2).
(3) Histopathologic factors for initial organ-specific metastasis by IDC
Breast cancer consists of histologically different groups which tend to spread to a specific initial metastatic site. The important predictive factors (fibrotic forcus, hormone receptor status, and ten or more nodal metastasis) for metastasis to specific organs in IDC patients were clearly demonstrated (3). Fibrotic forcus characteristics can thus be concluded to be the most important histologic factors for predicting metastasis.
(1) Clinical validation study of SNB
A Phase II study on the safety of SNB for the diagnosis of primary breast cancer without clinical axillary lymph node metastases in multicenters is currently underway. This study aims to evaluate the safety of a blue dye and radioisotope using SNB, and to compare the identification rate of SLN in Japan with that in the US and Europe.
(2) Neoadjuvant endocrine therapy
With the recent advances of aromatase inhibitors, a clinical randomized control study of neoadjuvant endocrine therapy for post-menopausal women with a hormone-sensitive tumor is on going. This study aims to evaluate the optimal duration of exemestan (4 months vs. 6 months).
● N. Wada ●
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