Radionuclide therapy was effective in slowing the growth of disseminated tumor cells (MLC) at an early stage of breast cancer in animal models. This was reported researchers in the January issue of the journal «January issue of the Journal of Nuclear Medicine». They found that radiopharmaceutical 223RaCl2, emitting alpha particles, not only affects the cells directly affected by radiation, but also has a significant effect on the radiation field outside the cells (ie background cells or bystander cells).
Breast cancer - the most common type of cancer in women in the United States. Although survival rates of patients are quite high, about 20% of women who survived the first five years after treatment, will eventually develop metastatic disease. In the formation of metastases involves circulating tumor cells, which are released from the primary tumor and get access to the circulatory system. These MLC can sustain active proliferation and become makrometastazy or remain dormant for many years before moving to the stage of activity.
"In connection with the renewal of interest in therapy with alpha particles and their capacity to sterilize the MLC, we focused on determining whether baystendera effect involved (bystander effect) in therapy 223RaCl2, and if so, whether it can be used for the treatment of PKD progression of the disease "- the scientists noted.
In a study of female mice were injected 600kBk or 0.50 / kg 223RaCl2, to create conditions for baystendera tumor cell inoculation. After 24 hours, the rodents were inakulirovany human estrogen receptor positive breast cancer cells thrice or negative (estrogen-receptor negative, progesterone receptor negative and HER2 negative) breast cancer cells. Bioluminescent intensity of the population inoculated with tumor cells were measured on the first day and every week after that.
Analysis of tumor burden has shown that PKD contains both within and outside redistributions range alpha particles emitted 223RaCl2 in both types of breast cancer cells. The tumor growth delay for each group monitored breast cancer cells. Estrogen-receptor positive breast cancer cells responded to treatment 50 and 600 kBq / kg of delayed growth for seven and 65 days, respectively. Negative cancer cells showed three 10-day delay in tumor growth in the group receiving 600 kBq / kg. No significant difference was observed in the triple negative cancer group administered with 50 kBq / kg of the drug, compared with the control group.
"Increased value baystendera effect in the study may indicate that an increase in the injection of radioactivity improves sterilization undetected dormant or growing slowly PKD in the bone marrow microenvironment. Thus, 223RaCl2 potentially could be one adjuvant treatment for individual patients in the early stages of breast cancer "- researchers noted.