Radiation Therapy And Chemotherapy

Radiation therapy uses high-energy ionizing radiation to kill the tumor cells and this procedure generally reduces the risk of cancer recurrence by approximately 70%. However, it often induces adverse side effects on normal tissues adjacent to the radiation site. For both of the above therapies the tumor should be within clinical detection range and accessible to therapeutic procedures. Chemotherapy is a major post-surgical treatment used to reduce the risk of cancer recurrence. Chemotherapy decreases the tumor size by affecting rapidly dividing and highly metabolizing cells, which are the main characteristics of malignant cells. A large number of chemotherapeutics are clinically available like Gemcitabine, doxorubicin, paclitaxel etc. In many

cases, a combination of two or more drugs will be used as a treatment regimen. However, chemotherapy causes side effects like hair loss (alopecia), fatigue, anemia etc., by acting on dividing cells and cells, which have high metabolic activities. Lack of specificity, multi drug resistance, drug clearance, altered bio-distribution and biotransformation are also common issues compelling to use high concentrations of chemotherapeutics. Therefore, targeted treatments are emerging as powerful techniques maximizing therapeutic index and reducing toxicity [9]. Although strategies targeting primary malignancies have improved markedly, there are no cures for clinical relapse and metastatic disease, which remains the underlying cause of death for the majority of cancer patients. Several new therapies based on biological agents such as nanoparticle drug delivery, stem cell based anticancer therapy, targeted antibody therapy, and cancer vaccines, which are currently in development, have been very effective in preclinical research, but they have not yet been shown to be effective in human clinical trials. Accordingly, a novel powerful cancer therapy with fewer side effects is urgently needed.