Current Status of Radiation Therapy in USA and the development of advanced Radiotherapy Equipment
演題番号 : S6-5
1:Division of Radiation Oncology, Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, U.S.A.
Radiation Therapy is critical component of Multidisciplinary approach for the cancer management for any site. Treatment of Cancer of the Head and Neck, Lung, Esophagus, Rectum, Anus, and Cervix has shown that combined chemoradiotherapy is superior compared to chemotherapy alone, radiotherapy alone or surgery alone regarding local control and survival. Concurrent chemoradiotherapy is standard for the above cancer if the patients could tolerate it. Normal tissue toxicity is is higher when concurrent chemoradiotherapy is used.Therefore, we have developed better targeted treatment physically and biologically to kill cancer cells without killing surrounding normal tissue cells.
Physically targeted treatment has been accomplished by higher energy of radiation therapy 60, Linear Accelerator with 6 MV, 10MV, 18 MV, and now proton therapy 100 MV-250 MV. One of reasons why this high energy equipment became popular is to spare normal tissues.
If patients were young and live long enough to manifest late toxicities or secondary malignancies, the more targeted radiotherapy given by higher energy and image guidance is beneficial.
Low dose of CT scan for screening lung cancer detected more stage I lung cancer which can be cured by surgery or stereotactic radiotherapy (SBRT). However we need to control tumor motion with 4D simulation when we treat small peripheral lesions.
Biologically, we started to check genetic mutation of the lung cancer such as EGFR, ALK, BRAF and K-Ras. If the tumor has EGFR mutation, we can use EGFR-TKI and radiotherapy which does not increase normal tissue toxicity.
In summary, higher energy equipment with imaging guided and molecular targeted treatment appear to be promising approach for lung cancer and other type of cancer.
In the future, molecular image guidance and targeted radiotherapy with molecular targeted systemic treatment will cure or suppress cancer growth without severe normal tissue toxicity.