Local radiotherapy for pleural dissemination of thymic tumors after initial treatment

概要

Pleural dissemination is a common pattern of failure after initial treatment of thymoma and thymic carcinoma, but there is no standardized treatment. There have been no large studies, to our knowledge, that investigated the efficacy of local irradiation for pleural disseminations of thymic tumors. As these tumors are relatively radiosensitive, we investigated the effectiveness of radiotherapy. Twenty patients underwent 33 series of local radiotherapy for 96 pleural dissemination lesions after initial treatment. Conventional radiotherapy, tomotherapy, and combination of the two were employed in 19, 13, and 1 series, respectively. The median follow- up period after the first irradiation for pleural dissemination was 46 months (range, 14-161). For all 20 patients, overall survival rates from initial radiotherapy for pleural dissemination were 100% at 3 years and 86% at 5 years. Progression-free survival rates after 33 series of radiotherapy were 30% at 3 years and 16% at 5 years. Local control rates for 96 lesions were 98% at 3 years and 96% at 5 years. In-field recurrence was observed in only 2 among the 96 lesions. One patient (5%) developed grade 3 radiation pneumonitis and another (5%) developed grade 3 pericardial effusion. No other serious adverse events were observed. When disseminated nodules can be covered within localized fields, local radiotherapy may be a treatment option. Using tomotherapy, multiple lesions can be treated safely.