Prospective Study of Stereotactic Body Radiation Therapy for Thymoma Inoma: Therapeutic Effect and Toxicity Assessment

Overview

For patients with unresectable or recurrent disease, radiation is routinely administered, often in combination with systemic chemotherapy. However, because of wide range of radiation, more complications of conventional radiotherapy limit its treatment dose. The local recurrence rates of conventional radiotherapy are dissatisfied.Stereotactic body radiation therapy(SBRT) well solved the problem above. On the one hand, by improving the single dose, it not only shortens the total radiation treatment, but also increases the total dose of equivalent biological effects.

Thymoma is mainly divided into two types, invasive and noninvasive type, and more than 60% of patients belong to noninvasive thymoma. When feasible, complete surgical resection is the primary treatment. There are quite a number of thymoma patients that has lost its surgical indications when diagnosed. Even after complete resection, the recurrence rate can be about 20%. For patients with unresectable or recurrent disease, radiation is routinely administered, often in combination with systemic chemotherapy. However, because of wide range of radiation, more complications of conventional radiotherapy limit its treatment dose. The local recurrence rates of conventional radiotherapy are up 16% to 45%. Moreover, it's not suitable for patients with severe heart and lung disease. Stereotactic body radiation therapy(SBRT) well solved the problem above. On the one hand, by improving the single dose, it not only shortens the total radiation treatment, but also increases the total dose of equivalent biological effects; On the other hand, SBRT, with more precise conformal radiation therapy, significantly reduces the damage to the surrounding normal tissues. Theoretically, SBRT can improve the local control, as well greatly reduces incidence of the radiation pneumonia, pericarditis, tracheitis, esophagitis and so on. However, few studies focused on the treatment of thymoma by SBRT, except two case reports Here we performed a prospective study on the treatment of thymoma by SBRT. The purpose of this prospective study was a preliminary evaluation of feasibility, efficacy and toxicity ofγ-SBRT in the treatment of thymoma.