He J et al. / Triple negative breast cancer 127 prognosis, different therapeutic strategies and marked difference in survival.10-12 Patients with triple-negative breast cancer cannot benefit from the targeted endocrine therapy and anti-HER-2 treatment. Therefore, for such patients, the only al- ternative strategy is chemotherapy as an adjuvant therapy of surgery and radiotherapy. Studies have demonstrated triple-negative breast cancer is more sensitive to chemotherapeutic drugs than breast cancer of other subtypes.13,14 However, the prog- nosis of triple-negative breast cancer is very poor and it is susceptible to recurrence, which may be contributed to the low pathological remission rate of triple-negative breast cancer. Therefore, in en- hanced chemotherapy, the pathological remission rate is a critical factor in improving the prognosis of triple-negative breast cancer. The sensitivity to chemotherapeutic drugs and local concentration are two crucial factors deter- mining the fate of cancer cells (especially the tu- mour stem cells) and the subsequent pathological remission rate.15 Traditionally, the pre-operative chemotherapy is carried out through intrave- nous infusion. Under this condition, the effective concentration of chemotherapeutic drugs in local lesion is relatively low and, therefore, the effec- tiveness will be achieved after prolonged courses of the treatment. In addition, intravenous chemo- therapy may result in drug resistance of cancer cells. Nevertheless, in the intra-arterial chemo- therapy, the effective concentration of chemo- therapeutic drugs in local lesion, surrounding tis- sues and lymph nodes is significantly elevated.16,17 Previously, the blood supply of breast cancer was considered to be mainly from internal mammary artery. Therefore, in superselective intra-arterial chemotherapy, the chemotherapeutic drugs were infused into internal mammary artery. However, in recent studies18-20, results revealed the lateral thoracic artery was the dominant feeding artery of breast cancer followed by thoracic artery and sub- scapular artery. At the same time, the metastasis of breast cancer is done through ipsilateral axillary lymph nodes which are supplied by thoracic artery and subscapular artery. Therefore, the optimal tar- get in superselective intra-arterial chemotherapy should be the blood vessel network in the breast cancer and the axillary arteries8 and the area sup- plied by these blood vessels is also called target region. In the present study, superselective intra- arterial chemotherapy was performed and the ef- fective concentration of chemotherapeutic drugs in the local target region was dramatically increased in unit time, resulting in increased time-density/ intensity. Therefore, the primary lesion and sur- rounding potential lesions as well as lymph nodes were effectively chemically treated which further increased the pathological remission rate and re- duced the local recurrence and the risk for distant metastasis. The favourable sensitivity to chemotherapeutic drugs but poor prognosis of triple-negative breast cancer may be contributed to the difficult detection of local skin metastases, lymph node metastases or even distant micrometastases. In traditional chem- otherapy, the effective concentration in local lesion is relatively low in unit time and subsequently the cancer cells can not be completely killed, which, however, may lead to drug resistance of cancer cells affecting the efficacy of chemotherapy. Our results showed the advantages of targeted chemotherapy in the increased efficacy, down-staging, improved lymph node metastasis, cCR, and pCR over tradi- tional chemotherapy (P<0.05). Furthermore, the mean course of targeted chemotherapy was only 15 days which was also shorter than that in the control group (31 days). These results revealed the superselective intra-arterial chemotherapy could increase the local effective concentration of chem- otherapeutic drugs, possess favourable efficacy demonstrated by the decrease in tumour size and rapidly control the disease progression, which are critical for the killing of cancer cells as soon as pos- sible. Pre-operative superselective intra-arterial chem- otherapy, on one hand, can increase the local ef- fective concentration after the regional infusion, and more cancer cells can be killed when com- pletely contacting with drugs. As a result, the tu- mour could be shrunk in a large scale. Therefore, the man-made spread of cancer cells during op- erations and post-operative recurrence as well as metastasis are prevented. On the other hand, the infused drugs are transferred into the systemic circulation. Therefore, not only local chemother- apy but systemic chemotherapy is carried out. In the present study, there was no significant differ- ence in the side effects of chemotherapy between both groups, which suggested the concentration of drugs in the systemic circulation was also com- parative with that in traditional chemotherapy. This effect is critical for the control of subclinical lesion and benefits for the complete remission in pathology. Moreover, the mortality in the targeted chemotherapy was lower than that in the control group, which also demonstrated the advantage of targeted chemotherapy in improving the progno- sis of triple-negative breast cancer. Radiol Oncol 2011; 45(2): 123-128.