cancer radiotherapy

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1. Building Cancer Immunity with Radiotherapy Gorby Castillo 5380253 2. What is Cancer? A disease involving abnormal cell growth that can spread to other parts of the body 3. Causes/Symptoms Causes 90% Environmental (carcinogens from tobacco/food, radiation, infection, lifestyle) 10% Genetic/hereditary Symptoms Dependent on cancer type 4. Treatments Surgery Radiotherapy Chemotherapy Immunotherapy 5. Surgery Direct tumor removal 6. Chemotherapy Anti-cancer drugs 7. Radiotherapy Damage DNA of cancer cells using ionizing radiation 8. Immunotherapy Use the bodys immune system to fight cancer cells 9. Radiotherapy: Mechanism DNA/Membrane Damage 10. Cell Death from Radiation Mitotic catastrophe Apoptosis Necrosis Autophagy Senescence 11. Mitotic Catastrophe Premature mitosis 12. Apoptosis Programmed cell death 13. Necrosis Loss of cell membrane integrity/DNA degradation 14. Autophagy Excessive catabolism of components, eating itself 15. Senescence Permanent cell cycle arrest 16. Closer look: Radiotherapy Can damage normal cells Different cancer types have different radiosensitivity High (leukemia, lymphoma, ovarian/testicular), ~30 Gy Moderate (breast, prostate, lung, colon), ~70 Gy Low (skin, kidney), too high to be safe Curability is usually reverse of radiosensitivity Therefore usually requires chemotherapy Intensity vs exposure constraint 17. Advances in Radiotherapy Advanced image guiding systems higher precision SABR (stereotactic ablative body radiation) Synchrotron MRT (microbeam radiotherapy) Pre-clinical testing due to unknown reason for low local tissue sensitivity 18. SABR Daily, minute, precise doses of radiation (2 Gy) 19. Synchrotron MRT High flux X-rays segmented into a lattice of micro-planar beams separated by plains of low dose radiation, allowing very high doses (over 100 Gy) of radiation 20. Immunotherapy: Mechanism White blood cells will attack targeted cancer cells 21. Closer Look: Immunotherapy Mechanism: bodys immune system will fight cancer cells Three Es of immunoediting Elimination Equilibrium Escape Limited to cancer cells which release high immunoactivators Cancer cells which release little/no immunoactivators are not affected 22. Elimination Cancer cells release immunoactivators which act as receptors for white blood cells to target 23. Equilibrium Surviving cancer cells grow and multiply/improve their resistance to white blood cells 24. Escape New cancer cell variants continue to attack the body without resistance from immune system 25. Combining Radiotherapy and Immunotherapy Positive Effects (2-15 Gy) Irradiated cancer cells are a good source of diverse immunoactivators Radiation activates MHC class I receptors in cancer cells, releasing more immunoactivators New immunoactivators are memorized and used for secondary cancers Negative Effects (Over 15 Gy) Cancer cells enters wound healing state when dosage is too high, releasing immunosupressant chemicals Immunosupressant chemicals prevent/inhibit release of immunoactivators such has MHC class I receptors 26. Radiotherapy + Immunotherapy 27. Conclusion Radiotherapy has become more precise due to technological advancement Immunotherapy is limited to cancer cells which release enough immunoactivators Radiotherapy can allow utilization of irradiated cancer cells in immunotherapy to increase effectiveness, with low radiation doses more effective in this case 28. References http://www.sciencedirect.com/science/article/pii/S03043835 15000300 http://www.annualreviews.org/doi/abs/10.1146/annurev.imm unol.22.012703.104803 http://www.cancernetwork.com/cancer-management http://www.who.int/mediacentre/factsheets/fs297/en/

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