Preclinical Evaluation Of Fulvestrant For Therapy And Prevention Of Breast Cancer-A Pilot Study

Breast cancer is the most common malignant tumor of women,which poses a threat to the survival of women in China and even the world.Studies have found that diagnosis at young age is associated with poor prognosis.Recent epidemiological data suggest that young women's breast cancer differs from that of older women in the cause,presenting a more aggressive development process.Compared with elderly patients,young patients usually have larger tumors,later stages,higher lymph node metastasis,lower rates of ER and PR,and higher HER2 expression rates.Although there has been a decline in breast cancer mortality in recent years,the five-year survival rate for advanced breast cancer patients with distant metastasis is still around 26%.Treatment for advanced breast cancer includes adjuvant chemotherapy,endocrine therapy,radiotherapy and possible surgical treatment.Locally controlled breast cancer is treated from local surgery to full mastectomy,including or not including radiotherapy.These treatments changed the appearance of the breast and affected the patient's image and quality of life.In order to reduce the risk of recurrence and death,patients with hormone-receptor-positive diseases are treated with endocrine therapy for 5 to 10 years.Fulvestrant is a selective estrogen receptor degradation,combined with the ER with high affinity,the combination complex is not stable,which will accelerate the degradation,led to lower the ER alpha cells.The"leaf" theory holds that breast cancer is a leaf disease,not confined to the visible catheter or lobule structure.If this theory is correct,surgical resection of just breast tumor is not enough.For DCIS or precancerous lesions,intraductal injection of active drugs may be an effective method.Then,the method of intraductal injection in the breast cancer model of SD rats induced by the chemical carcinogen MNU was used to study the prevention and treatment effect of fulvestrant on breast cancer.The rats were divided into three groups,the intraductal injection of fulvestrant group,the intramuscular injection of the fulvestrant group and the intraductal injection of the normal saline group,to compare the incidence of tumor in each group and the tumor-free survival of Kaplan-Meier analysis.Although there was no statistically significant difference in the incidence of tumor in whether prevention experiment or treatment experiment of fulvestrant for breast cancer between three group,but the tumor-free survival analysis indicated statistically significant difference,and the intravenous injection group was optimal.It is effective in the prevention and treatment of breast tumors by intraductal injection of endocrine drugs in the carcinogenic model of breast cancer.