A Phase II Study of Simultaneous Modulated Accelerated Radiation Therapy Concurrent With Chemotherapy in Patients With Esophageal Squamous Cell Carcinoma

Esophageal cancer is one of the most common malignant diseases in China, especially in Chaoshan region. Concurrent chemoradiotherapy is the standard non-surgical treatment method for this disease and the radiation schedule is about 50.4~60 Gray (Gy) in total, 1.8~2Gy per fraction generally. However, although with such comprehensive method, noncontrol of local disease or recurrence is still the main reason of failure. Most patients with esophageal cancer suffer from malnutrition. A number of factors including hypoxic, inflammation, radioresistance and accelerated repopulation may contribute to local failures of disease after treatment; therefore a higher radiation biological equivalent dose (BED) will improve the local control probability. Although the intergroup 0123 (INT123) trial had shown that simply increasing total radiation dose could not gain better local control or overall survival rate, however, the ability of this trial to test the potential benefits of higher radiation dose could be compromized by the deficiencies within them, such as, observation bias,large radiated target volume and usage of conventional radiation technique. In other words, the probability that increasing radiation may help improving the control of disease should not be denied. Modern radiation techniques, such as intensity modulation radiation therapy (IMRT), specially, are able to improve the coverage of target volumes and sparing of critical structures, while increase the total radiation dose. By using simultaneous modulated accelerated radiation therapy (SMART) technique, the doses to the relevant normal organs per fraction could be reduced significantly, while the doses to tumor could be increased to higher than 2Gy. Thus reach the double goal of protection of normal tissues, increasing total radiation Equivalent Uniform Dose (EUD). Dosimetric study has proven the feasibility and superiority of SMART-base IMRT in radiation treatment of esophageal cancer, compared with conventional technique. Overall, SMART-base IMRT concurrent with chemotherapy may improve the local control and overall survival rate of patients with esophageal cancer; Meanwhile, the acute and late toxicities would be tolerable and slighter than that of conventional technique.