The number of new cases of female breast cancer was 128.5 per 100,000 women in 2020 in the US [1]. The death rate was 20.1 per 100,000 women per year [1]. Breast cancer frequently metastasizes first to the axillary lymph nodes near the affected breast.

In the treatment of metastatic lymph nodes using the “lymphatic drug delivery system,” anticancer drugs are administered directly to multiple lymph nodes, including sentinel lymph nodes. Unlike systemic chemotherapy, in which anticancer drugs are injected intravenously, very small amounts of highly concentrated drugs can be selectively delivered to lymph nodes in the early stages of metastasis.

Therefore, it is possible to target metastatic lymph nodes without inducing serious side effects. [2, 3].

Figure description
The lymph node where the cancer first metastasizes is called the sentinel lymph node. In the treatment of metastatic lymph nodes of breast cancer using the lymphatic drug delivery system, anticancer drugs are injected directly into multiple axillary lymph nodes, including the sentinel lymph node, which can be identified close to the primary tumor. The anticancer drug remains for a long time in the lymph nodes and is delivered from upstream to downstream lymph nodes via lymphatic vessels. Therefore, the treatment is expected to be effective not only for sentinel lymph nodes but also downstream lymph nodes with micrometastases.

References
[1] National Cancer Institute, Cancer Stat Facts: Female Breast Cancer, 2020.
[2] T. Kodama, D. Matsuki, A. Tada, K. Takeda, S. Mori, New concept for the prevention and treatment of metastatic lymph nodes using chemotherapy administered via the lymphatic network, Scientific reports, 6 (2016) 32506.
[3] R. Fukumura, A. Sukhbaatar, R. Mishura, M. Sakamoto, S. Mori, T. Kodama, Study of the physicochemical properties of drugs suitable for administration using a lymphatic drug delivery system, Cancer science, (2021).